Art. XLIX.—The Volcanoes of the Pacific.
[Read before the Wellington Philosophical Society, 17th August, 1898.]
First Lines of Activity.
In December, 1894, I went down to Tonga and Samoa from Auckland in the s.s. “Upolu.” Whilst lying at the wharf at Nukualofa, the capital of Tongatabu, the most southern of the three great islands of Tonga (the middle one being named Hapaai and the northern island Vavau), the steamer was shaken against the wharf by a sharp earthquake shock. No one took any notice of the matter, as earthquake shocks are common in Tonga; but it led me to inquire further into the question, and my inquiries resulted in finding that the situation of this particular group of islands will be found most interesting to the student of earthquake phenomena in the Pacific.
At Auckland I was well acquainted with the remarkable group of extinct volcanoes surrounding Dairy Plat—including
Mount Eden—upon the isthmus connecting that city with Onehunga. We all know the phenomena of our hot-lakes district, White Island, and the Hanmer Plains. The Kermadecs are also volcanic, and liable to great earthquake shocks. The longitude of these spots, roughly calculated from the poor maps in a country library, is as follows: Hanmer Plains, 172° 45′ E.; Tongariro, 175° 48′ E.; White Island, 177° 12′ E.; Auckland, 174° 45′ E.; and the Kermadecs, 178° W.
The distance from Tongariro to the Whakaari Volcano (White Island) is 120 nautical miles. Over the whole distance, according to Dr. Hochstetter in his geology of New Zealand, almost in the very line between these two active craters, volcanic phenomena “seethe, bubble, and steam from more than a thousand crevices and fissures that channel the lava-beds of which the soil consists, a sure prognostic of the still smouldering fire in the depths below; whilst numerous fresh-water lakes—of which Lake Taupo is the largest (twenty miles in diameter)—fill up the large depressions of the ground. This is the lake district so famous for its boiling springs, its steaming fumaroles, solfataras, and bubbling mud-basins.” I give the extract now, in order that members may fully realise the phenomena close to their doors—along a distance of 120 miles—before I carry them to the evidences of much greater phenomena in the Pacific.
Mount Egmont is also an extinct crater: longitude 174° E.; height, 8,280 ft.
Almost every volume of our Transactions contains valuable references and tabulations by Sir James Hector of earthquake phenomena, to which I refer members; and I would also refer them to the excellent earthquake papers by Professor Hutton, Mr. A. McKay, Mr. Field, and other contributors. We live in New Zealand in the midst of unaccountable earth-movements, as it were; but it may be that by arranging for the establishment of seismitic stations in the neighbouring islands of the Pacific—to which I am about to refer—we may begin to understand the cause of these movements a little more clearly than at present. In one of his papers* Mr. McKay placed the centre of the 1888 disturbance of September and October in the Amuri district (Hanmer Plains), at Glen Wye, the force of the shock diminishing in all directions from this particular part, and Sir James Hector agreed. Perhaps by throwing into one paper all the facts at my disposal of Pacific phenomena a wider range for earth-movements will be granted by geologists.
It has been stated that during our great Tarawera eruption
[Footnote] * Trans. N.Z. Inst., vol. xxi., p. 509
of 1886 the volcano of Kilauea, at the Sandwich Islands, was extremely quiescent.
I fancy, also, that Professor Milne'a seismometers register earth-movements to a distance of three thousand miles, and that through an arc of the globe; and it has even been stated that a late great earthquake in Japan was felt at the Isle of Wight, in England.
The object of this present paper is only to collect and supply the detailed information concerning the volcanoes of the Pacific, which I scarcely think other writers could have had the opportunity of observing.
It will be found, I think, that usually an outburst at one place affects some other place perhaps three or four hundred or even a thousand miles away, and sometimes even at a greater distance.
A late issue of the Rangitikei Advocate says: “It would appear from the conformation of the country around Ruapehu that the district for a considerable distance has been subjected to a periodical covering. The surveyors who have had occasion to dig trenches have found 1ft. of soil 3 ft. below the present surface, after having gone through various thicknesses of scoria and pumice, which makes it very probable that Ruapehu has a periodical burst-up.” Such periodical outbursts may imply internal pressure accumulating from a great distance.
The shock of the great earthquake that destroyed the City of Lisbon (1st November, 1755) pervaded an area of 700,000 miles, or the twelfth part of the circumference of the globe. “It was felt in the Alps, on the coast of Sweden, into the Antilles, Antigua, Barbadoes, and Martinique; in the great Canadian lakes, in Thuringia, in the flat country of Northern Germany, and in the small inland lakes on the shores of the Baltic. Remote springs were interrupted in their flow, and the hot springs of Toplitz dried up and returned, inundating everything around, and having their waters coloured with iron, ochre. A portion of the earth's surface four times greater than that of Europe was simultaneously shaken.”
I wish, therefore, to call the attention of members to volcanic phenomena in the Pacific, in order that we may better understand what is occurring here in New Zealand.
The longitude of the Tongan group lies between 172° and 175° W. At Nukualofa I had the pleasure of meeting Mr. C. D. Whitcombe, the courteous Foreign Secretary of the little kingdom, who informed me that he had just returned from investigating the remarkable phenomena at Falcon Island. This was the island which a few years previously had been thrown up in a night, where formerly a reef only—named the Falcon Reef, after H.M.S. “Falcon”—existed.
In the same month—-December, 1894—-when I was at Tongatabu, the report, had come in that Falcon Island had disappeared. Reports had previously been made that the island was gradually washing away, the sea being discoloured all around for some five miles owing to the erosion. The Tongan Government therefore, on the 21st December, sent Mr. Whitcombe down, with Captain John Cassels, Acting Harhourmaster, and some other gentlemen, to inquire into the actual state of things ac the island. Falcon Island lies about forty-five miles north-north-west of Nukualofa, in longitude 175° 20′.
Captain Cassels and a Mr. O'Connor swain through the surf, which there swarmed with small sharks. They found the island, to be “cold, steep, water of 20 fathoms all round, about a mile and a quarter in diameter, and three and a half in circumference. At the southern end about 50 ft, high; in the centre a fresh-water mineral lake about 4 ft. to 5 ft. deep, with a solid-rock bottom. In places very hot to the feet, as Mr. O'Connor found.” They had to take their boots off when swimming from the boat, which, lay outside the surf. The island itself was a mass of red and black scoria, whose gradual washing-away caused the discolouration of the surrounding sea. I have given Captain Cassels's own words concerning his visit. I also present to our Museum specimens of the red and black scoria, and of the solid-rock bottom of the lake, which Captain Cassels tied up in his shirt when swimming back to the boat. The formation of the, scoria is remarkable. The little spheres and oblates, if water-worn, must have been so formed by submarine action, as there was no active volcano on the island, and little vegetation, so far as I could make out. The black scoria is partly composed of the little hollow bombs, somewhat similar, I believe, to those thrown out in the great eruption of Tarawera in June, 1886, and at other times before and since. The formation of these little bombs is no doubt easily explained. But in Miss Bird's account, of the great eruption of Mauna Loa, Sandwich Islands, in 1868, the volcanic phenomena there displayed, forces in nature of which we know little or nothing. The motion of the land during the eruption was “vertical, rotary, lateral and undulating”; mountains fell and split up in all directions; the purging of the imprisoned lava was heard through the ground; its flow of twenty miles underground; its bursting through the soil in huge fountains, rotating towards the south; “in the air both lava and stones always rotated towards the south.”
It will be noticed, top, that the black scoria gravel is much smaller than the brown gravel; but this may be only a small local; difference in the strata. I am well aware that the lava from different volcanoes is different. The solid-rock bottom
appears to be volcanic tufa. Sir James Hector tells me that this is a very interesting rock, being a form of rhyolite containing spherulitic grains of pearlite embedded in a rough silicious and feldspathic base, which also contains sparkling grains and subcrystalline groupings of white iron-pyrites. The rock is a most beautiful object under the microscope with a strong direct illumination.
I also include the following description of his visit, which Mr. Whitcombe gave me verbatim: “I was sent with Captain Cassels on the 20th December, 1894, to report upon Falcon Island. On the 21st, at noon, Falcon Island loomed on western bow, northward; Tofua and Kao on eastern bow. Boat put off from ship to visit it. Report required because one ship had reported its disappearance and another ship had stated its emergence and extension, with discoloured water five miles round. Captain Cassels, Mr. O'Connor, and Bolutele (the Premier's clerk) accompanied me. Landing very difficult, as seas dashed up the steep slopes of island. Deep water (40 fathoms) close to island. Discoloured water three to four miles from island caused by detritus from it. Party had to wade and swim to island, taking a rope and leaving a man in boat. Shoals of small 5 ft. to 7 ft. sharks assailed us. Found island covered with coarse black gravel. Water in lagoon very clear, with strong mineral chloride flavour. In one part the soil of the island was red-hot, so much so that it blistered Cassels's and O'Connor's feet. South-east end of island highest part—50 ft., varying to 20 ft. Circumference of island, four miles. Length, a mile and a half. Tongan Ensign hoisted, and fourteen cocoanut-trees planted. Taken possession of in name of King George II. of Tonga. Its name, Kahekahe Fefine (woman). This island (Falcon) sprang up in 1885. Another island which had sprung up some years previously between Late and Kao the king named Kahekahe Tangata (man).”
In my scrap-book I find the following extract touching the first appearance of the island: “The intelligence officer of the American warship ‘Mohican’ forwards the following to the Press: ‘In compliance with instructions received in July from Admiral McCauley, the American corvette “Mohican,” Commander Day, made a special trip to an island formed by volcanic action since October last. At a distance of fifteen miles steam could be discerned rising in the air above the former site of the Falcon Shoal. On arriving at the spot the “Mohican “steamed round, taking bearings of its positions, and sketches and photographs of its contour and appearance. The island is of circular shape, 230 ft. high, and a mile and a half wide. It has a steaming crater on the east side. To the extreme west there is a noticeable wreath of smoke. On
taking soundings good anchorage was found on the north side of the island. The longitude is 175° 20′ W., and the latitude 20° 20′ S. The island is situated forty-eight miles north-north-west of Nukualofa. The impression conveyed by its appearance was that the bed of the ocean had been uplifted out of the water.’ “
The island had therefore lost 180 ft. in height between its upheaval in October, 1885, and Mr. Whitcombe's visit in December, 1894. There is nothing very remarkable in this, as volcanic islands have been thrown up and subsided in European seas. The lavas, scoria, ash, or tufa of which they are composed are particularly subject to the wear-and-tear, of rain, wind, and tide, and more especially of tidal wave, or, rather, earthquake wave, which is awfully destructive. The above data, however, are interesting.
I also give an extract from our Wellington shipping news of 1895 concerning H.M.S. “Penguin's” cruise and survey: “H.M.S. ‘Penguin,’ which came into port yesterday afternoon, has been engaged since July last in surveying from Auckland to Tonga, thence to Samoa, and back to Tonga, in addition to surveying at the Falcon Islands. Her officers claim that they have the record for deep-sea soundings, and certainly some very extraordinary depths were obtained. The warship left Nukualofa, Tonga, on the 21st December, and on the 26th soundings to the extent of 4,940 fathoms were obtained, but the wire which was being used parted and was lost. Later in the day, however, 5,022 fathoms was reached, in latitude 23° 39′ S., longitude 175° 4′ W. On the 30th December a depth of 5,147 fathoms was reached, in latitude 28° 44′ S., and longitude 176° 4′ W. On the 31st December, however, the still greater depth of 5,155 fathoms was reached, in latitude 30° 27′ S., and longitude 176° 39′ W. Red clay was brought up from the greatest depth. The ‘Penguin’ takes in a supply of coal here, and sails on Saturday for the Bluff, and thence to Hobart, taking soundings as she goes.”
Upon the above, Rear-Admiral Wharton, writing to the Times, remarks: “It may interest some of your readers to know that some spots have recently been found in the South Pacific Ocean where the water is deeper than anywhere hitherto known. Her Majesty's surveying ship ‘Penguin,’ while returning from the Tonga Group to New Zealand, has sounded in three places where the depth exceeds 5,000 fathoms. Up to the present the deepest water found was to the north-eastward of Japan, where in 1874 the United States steamer ‘Tuscarora’ obtained a cast of 4,655 fathoms. The ‘Penguin's’ soundings are 5,027, 5,147, and 5,155 fathoms. The increase is therefore 500 fathoms, or 3,000 ft. These
soundings are separated from one another by water much less deep, and the bottoms may not be connected. The distance from the two extreme soundings is 450 miles. Specimens of the bottom were recovered from the two deeper soundings, and prove to be the usual red clay found in all the deepest parts of the oceans. These soundings afford additional evidence of the observed fact that the deepest holes are not in the centres of the oceans, but are near land, as two of them are within a hundred miles of the islands of the Kermadec Group, and the other not far from a shoal. Doubtless deeper depressions in the bed of the sea are yet to be found, but the fact that this sounding of 30,920 ft. shows that the ocean contains depressions below the surface greater than the elevation of the highest known mountains is perhaps worthy of record.”
As to the question of heights and depths, a sounding has recently been taken in the Pacific Ocean, near the coast of Japan, which shows a depth of 29,400 ft., or approximately five miles and a half. This is a little more than the height of the loftiest mountain—Mount Everest—which is situated in the Himalayan Range, to the north of India. It has been suggested, as one theory of the formation of mountain-ranges, that they represent the crumpling-up, or buckling, of the earth's crust under the severe contraction strains that were set up as the surface of the globe solidified. If this be true, the deep ocean valleys or gorges, such as this off the coast of Japan, must be the result of the same action. Taken in connection with the loftiest mountain, this sounding gives a difference in distance from the earth's centre of about twelve miles, or 1–333 of the earth's radius.
On our way to Tonga we passed Pylstaart Island (22° 23′ south latitude, 176° 7′ north longitude; height, 700 ft.; uninhabited), which I certainly should consider to be formed by volcanic upheaval.
The visitor to Tonga cannot fail to be struck by the numerous little islets standing upon the reefs at the different entrances to Nukualofa and Vavau—their flat tops and steep-sides, and how the waves are undermining them and wasting the solid coral away. He naturally concludes that these little spots must have been upheaved from the sea, and that not so very long ago, and by one and the same upheaval.
On the 28th the steamer left Nukualofa for Hapaai (distance, 132 miles). On the way I noticed Tofoa, or Tofua (1,890 ft.), and Kao, two grand huge dim-looking mountains running up to 3,000 ft. I think Tofua is more constantly in action than Kao (3,030 ft.), which only emits puffs of steam occasionally from its sides. Longitude, about 175° W. The weather was too thick for us (after leaving Hapaai for Vavau) to notice the smoke of the volcano on Tofua.- (It was to that
island the poor Wesleyan Tongans were deported daring the late religious persecutions there.)
I did not see Metis Rock, about thirty miles south-west of Vavau. This little island is composed of almost solid sulphur. Hundreds of tons could, be gathered there. The rock is about 100 yards in diameter and some 20 ft. high. There is no anchorage; a vessel would have to lie off and on. The rock, of course, is purely volcanic, as it is constantly seen emitting small puffs of steam. Calm weather, May, June, and July. Mr. A. W. Mackay, of Nukualofa, who has visited the rock, kindly gave me this information. Longitude, 174° 47′ W. Boats and punts would have to be used for loading the sulphur, but the Union Steamship Company's steamers could call for quantities, say, of 50 tons at a time.
Mr. Whitcombe has since written to me as follows: “Metis Island, in the Vavau Group, was last in eruption in 1886. It is called by the natives generally Fonua-fooa (new land,) and is about 151ft. in height.* There is another Fonua-fooa in the Tongatabu Group—-viz., Falcon Island. Metis is a rock of no great size—perhaps a mile in diameter, with a boundary reef round it. Large deposits of sulphur may also be found on Late. Island, and also on Fonualei Island. These islands are seldom visited. Deep water up to reefs, and also deep water inside (with occasional inner reefs and shoals), with one or more deep-water channels leading from the ocean into the inner water. No fresh water on any of them. With the exception of a small brook on Eua, there is not a running stream on any of the islands of the Tongan Group.”
I might be allowed to digress here to give a brief, list of other sulphur deposits in the islands besides Metis Rock, seeing that there has been a scarcity of sulphur lately, owing, I believe, to the Spanish-American war (1898): (1.) Late Island and Fonualei Island, in the Tongan Group. (2.) White Island, on our own-New Zealand coast; but workmen do not care to stay there now, owing to earthquake movement. (3.) The Kermadecs: schooners can load “off and on.” (4.) Hunter or Fearn Island, about 180 miles south-west of Kandavu. Hundreds of tons of sulphur are there to be had, and it is fairly pure, but landing is difficult. (5.) There are sulphur islands in the New Hebrides Group, which may be worked from Vila. (6.) Tanna, of course, contains a lot of sulphur. Four miles back from the anchorage—Port Resolution, which was partly destroyed by late earthquakes, which I shall speak of directly—in the direction of the active cone of the volcano, there is a valley, and by prodding with a walking-
[Footnote] * A different estimate this to Mr. A. W. Mackay's.
stick stick an excellent bed of pure sulphur will be found. Vila is on the Sandwich Island, New Hebrides, and many steamers call there now. The New Hebrides are under English and French protection. (7.) In the Loyalties there are sulphur deposits, belonging now to France. (8.) At Greet Harbour, New Britain, where Germany has a coaling station, there is a sulphur point. Sulphur has been found in this group at the foot of the Mother and. Two Daughters Volcanoes. (9.) There are also sulphur deposits on the New Guinea coast. I mention these facts now in case sulphur should be in commercial demand. It could form an adjunct to our New Zealand trade. I supplied what information I could upon this point a few years since to some English sulphur-miners, who wanted to dig and refine the deposits of ore in the Pacific. There is also a good deal of sulphur-ore to be obtained in our own hot-lakes district in New Zealand, some friends of mine in Auckland—the Messrs. Nathan—sending down some hundreds of ton's of it to the port
The Island of Niu-afu lies in 15° 34′ south latitude, 175° 40′ 40″ west longitude, and belongs to Tonga. Mr. Tarvis, one of our good English colonists in the Pacific, in-formed me that he resided on the island at the time of the eruption—about August, 1886. (The great eruption at Tarawera, New Zealand, was in June of that year.) About 7p.m. the earthquake began by gently swaying the island, and continued until 12 p.m., to the fright of all the inhabitants—some seven hundred people—who aimlessly wandered about, carrying the old and feeble to the highest land for safety. At 12 p.m. occurred a tremendous report like the discharge of a 60-ton gun, and a great rocket ascended from the lake to a distance of some 800 to 1,000 yards. The shaking of the island then ceased. From the spot where the rocket ascended an active volcano formed, and continued for seventeen days, throwing up sand, stones, and water. The cocoanut-trees were all ruined by the water and sand, which, falling steadily, and cementing on the leaves, broke them down by the mere accumulation of weight. In different parts of the island the deposit from the volcano averaged 2ft. to 20ft., crushing everything beneath it. During the eruption lightning was constantly playing around the island, darting occasionally into the groves of cocoanuts, and smashing down the trees.
I gathered from Mr. Tarvis, as well as I can remember, that Niu-afu is an island of about thirty miles in circumference, the water of the inner lake being of a mineral nature, and some four or five miles across. The Admiralty instructions only make Niu-afu; or Good. Hope, Island three miles and a half north to south and three miles east to west; about 500ft. to 600ft. high and well wooded to the summit. The centre of
the island—an old crater—is filled with brackish water, in which are hot springs. A severe eruption took place in 1853—not so long before the great earthquake in Wellington in 1854—when a village was destroyed, and many lives were lost. On the 12th April, 1867, another eruption occurred, but without loss of life. This last outbreak was on the south end of the island. I am as particular as I can be about dates, as I wish to point out to members that our great New Zealand volcanic eruptions approximate somewhat in date to those of Tonga.
I had only the pleasure of one conversation with Mr. Tarvis, and somewhat hurried at that, as he was returning to his schooner; but I immediately jotted down in my notebook, as well as I could remember, the tenor of what he told me—I remember now he stated that the new crater formed immediately in the centre of the inner lake, where it soon reared itself a little cone of 50ft. or 60ft. in height. This outbreak of 1886 and the 1853 outbreak—making, of course, due allowance for the guesswork as to exact dates—approach so closely to our Tarawera eruption of 1886 and the great Wellington earth-movement of 1853–54 that I think I am justified in concluding that the whole line of activity to which I am referring is in some manner influenced by the same seismic phenomena. (It has been stated that when Mount Hecla, in Iceland, is in eruption Vesuvius is quiescent, and when Etna or Vesuvius is in eruption Hecla is quiescent; but I only make the statement for what it is worth, as I cannot vouch for it as fact.)
According to Mr. Tarvis, Niu-afu is famous for three things: (1.) Earthquakes. (2.) Growing the largest cocoanuts in the Pacific. (3.) The marau-bird, which lays an egg quite out of proportion to its size. This bird is about the size of a pigeon, and yet lays an egg as large as that of a goose. The egg hatches of itself in the sand, or if placed in a drawer or box where there is a certain amount of heat. The bird is only known in Niu-afu in the South Pacific. It appears to be peculiar to volcanic islands, where the sand is loose. The name of the island is spelt “Niue Foou,” “Niua Foou,” and “Niu-afu.” Mr. Tarvis very kindly gave me two of the island's cocoanuts. I gave one to our Museum.
As I have said, the date of these disturbances it is necessary to remember—Tarawera, June, 1886; longitude 176° 25: Niu-afu, August, 1886; longitude 175° 40′: and Falcon Island (since October, 1885), 175° 20′. As I have also said, I can only vouch for the first date, as the other two I am not absolutely certain of. Within a few months we have evidence of an enormous eruption along this one parallel of longitude, the grandeur of which astonished all beholders. The distance from Niu-afu to Tarawera is close upon fifteen hundred
miles. As air, water and earth waves follow the same laws which are recognised by the theory of motion, I think I am justified in holding that these special volcanic manifestations were by some means connected.
A certain amount of confusion may arise in the minds of persons not acquainted with the exact pronunciation of names of places in the Pacific (the Tongese, for instance, pronounce each vowel), and I will explain more fully this name “Niu-afu.” Mr. Tarvis, who resides there, spelt it to me as I write it. Angas spells it “Nuia Foou.” The Admiralty sailing directions for the Central Pacific name it “Niu-afu,” or Good Hope Island. Other writers spell it “Niu-fou.”
The little island, as I have said, lies about thirty-five miles north and by west from Vavau. This name must not be confused with Nei-afo, or Neafu, the name of the grand harbour of the Island of Vavau itself; nor with Nine, which is the native name for Savage Island, an important island standing by itself to the eastward, containing some five thousand people.
Again, confusion arises from the very nomenclature of some of the islands. There is Fearn, or Hunter, Island, to the south-west of Kandavu, named, I expect, after Captain Fearn, of the “Hunter,” who cruised in the Pacific in 1790 to 1798, and discovered another Hunter Island to the northward of Santa Cruz; and upon the map of the Pacific attached to this paper will be seen another Hunter Island to the north-west of Fiji; there are also some Hunter Isles in the Marshall Group: so that we have no less than five Hunter Islands, which must not be confused with each other.
It was stated to me by a lady in Tonga that one sharp earthquake shock occurred on the 8th October, 1894, about the time of a severe earthquake at the New Hebrides; also, that she remembered experiencing a sharp shock about the time of a late great earthquake in South America. If this observer's dates are correct—and they were given to me in perfect good faith—the position of Tonga would be an admirable one for a seismitic station.
No doubt the argument can be used that water may be always sinking through the earth's crust to the central heat, which, converting it into steam, throws it back again by means of the different safety-valves we call volcanoes. Furthermore, that, as the crust of the earth is always in movement, and contracting slightly by slickenside pressure, our supply of water will have farther and farther to go to seek the central heat; volcanic safety-valves may grow fewer in number, and the oceans eventually dry up. Volcanoes are therefore our best friends, for when they cease we may know
that this globe will not support human life, in consequence of the absence of surface-water, which has been absorbed by the planet itself. Even granite requires a certain amount of water to preserve its crystallization. I should therefore conclude that there is water still in the body of our moon, but no surface water, and that the volcanoes there are all extinct.
The phenomena of the earth-wave attending earthquakes can perhaps be seen by the following simple experiment Take a couple of milk-dishes; stand one inside the other, but separate the two with three small blocks of wood; pour into the top dish a bucket of milk, fresh from the cow; let it stand for a couple of hours, until the cream is fairly rising; then into the lower dish pour a bucket of boiling water: this will have the effect of altering the temperature of the milk, causing the cream to form into a skin on the top of the milk and beneath this skin the imprisoned heat-waves in the milk will fairly exemplify the earth-waves during an earthquake. The cream-skin moves up and down as the imprisoned heat below endeavours to find vent, but it never moves lengthways. The circular motion of the ground in an earthquake, too, can be noticed in the cream-skin as the heat-bubbles rise through the milk. We can see—(1) The up ward thrust; (2) the wave motion; (3) the side-to-side motion; and (4) the circular motion experienced during an earthquake fairly exemplified in this simple experiment. The rapidity with which the waves beneath the skin or crust move across the pan is only an instance of the velocity of motion, whether in light, heat, or sound. The wave travels under the sea just as readily as in the milk-pan, forming the tidal wave.
Mr. Napier Bell tells me that to account for the tidal wave he suspended a milk-pan, filled it with water and then sharply struck the side. But this did not carry the wave as he expected. (If he tries heating the milk he will see the waves readily and quickly following each other.) The cream-skin, if as rigid as our earth's crust, would, I suppose, crack as the waves pass beneath it. Now, as all the great volcanoes ate close to or in the sea; it is evident that sea-water pouring through the earth's crevices—of which there are many everywhere—reaching the central heat, is there converted into steam, which, becoming highly heated and imprisoned, seeks an outlet in waves along the crust of the earth, just as the heated milk moves beneath its cream-skin. I have noticed, also, that brine in which meat has been cured, after boiling, and when cooling, shows movements similar, I expect, to those observed in boiling-lava streams.
From Mounts Erebus and Terror in the Antarctic to Mount Hecla in Iceland, around and through the Pacific Ocean, and towards the Mediterranean and elsewhere, there
are, I think, a sufficient number of volcanic safety-valves—two hundred and seventy to three hundred—to keep our present supply of water upon the surface. The local Tongan earthquakes are therefore, no doubt, connected with the eruptions of Tofoa, which is a high flat-topped island nearly five-miles in diameter, situated about fifteen miles to the westward of the Hapaai Group, 1,890 ft. high, and is a volcano in continual activity. But it. may be—I do not say it is—that this particular group of islands is affected by distant earth-movements in Java and South America. We shall be able to judge better, after we establish seismitic stations in this most interesting position of the earth's volcanic energy, whether Tofoa acts in sympathetic connection with Java and Central and South America.
I, of course, ask to be excused for venturing to express any opinion, or to draw any conclusions in the course of this paper, upon the facts I have observed and collected. My simple duty is only in this paper to record those facts. But the subject is so interesting, and the field of observation so new, that it is difficult to refrain from drawing some conclusions. I shall therefore feel favoured by members correcting me when I err, as I have not had the time to study volcanology, and should like to be informed correctly concerning the facts I have noted.
Kao Island, lying two miles and a half north-north-east of Tofoa, is 3,030 ft. high, but not an active volcano. Captain Sir Everard Home, in H.M.S. “Calliope,” who visited the Friendly Islands in 1852, reported, that a volcano, or the indications of one, had been perceived about half-way between the Islands of Kao and Lette; and about twelve months previously smoke had been seen issuing from the surface of the sea. This date approaches somewhat the great earthquakes in Wellington.
Returning for a moment to Metis and Lette, I might mention that an island of volcanic origin, about 200 yards long and 110 ft. high, situated in latitude 19° 11′ S., longitude 174° 49′ W., was passed by H.M.S. “Sapphire” on the 16th April, 1878. It ejected quantities of white smoke, and appeared to be covered with sulphur. The island would seem to be identical with the rock, 29 ft. high, reported by the German ship “Metis” in 1875, the effects of volcanic acfion having probably added to its size. During my late trip I passed near this rock, and, as I have said, Mr. A. W. Mackay informed me that it was one mass of sulphur. The different estimates of height and size of this rock which I have given are interesting.
About six miles northward of Honga Tonga Island, which is two miles north-east of Honga Hapaai, lying to the north-west
of Tongatabu, there must be a submarine volcano, as smoke has been seen issuing from the sea. Then, Lette Island, in latitude 18° 50′ S., longitude 174° 37′ W., is high and volcanic, the peak being 1,790 ft. high. The large crater gives out a vaporous-looking smoke and small jets issue from its side. This Lette Island is the same that Mr. Whitcombe referred to in his letter.
I will roughly give the longitude of those places already, touched upon, in order that we may see at a glance the first line of volcanic action to which I desire to call attention in the Pacific Ocean: Mount Egmont, 174° E.; Tarawera, 176° 25′ E.; Tongariro, Ngatmihoe, and Ruapehu, 175° 48′ E.; White Island, 177° 12′ E.; Auckland, 174° 45′ E.; The Kermadecs, 178° W.; Pylstaart, 176° 7′ W.; Falcon Island, 176° 7′ W.; Lette, 174° 37′ W.; Metis Rock, 174° 49′ W.; Niu-afu, 175° 40′ W.: to which I may be allowed to add—Chatham Islands, 176° W.; Bounty and Antipodes Islands, 179° E.; Campbell Island, 169° E.; Auckland Island, 166° E.; Emerald Island, 163° E.; Macquarie Island, 159° E.; and Mounts Erebus and Terror, 178° 30′ E. (Other active volcanoes have just been discovered in Grahamsland, immediately to the south of Cape Horn. I only mention this here, but they form no part of this first line of activity, although they may be connected with it.)
Sir James Hector has referred, in his lectures to us about his late trip to these antarctic islands, to the gigantic nature of some of the remains of volcanoes upon them. I do not think them gigantic in comparison with the volcanoes of, say, the Sandwich Group. But I might ask geologists to consider whether the fact of so many of the earth's volcanoes being in or near deep water results from the sea-water finding its way, by various faults and crevices, through the earth's crust, reaching thereby the central heat, and immediately, at or near the fault or crevice, being thrown out again by volcanic vents even a thousand miles apart along the particular line of crevices immediately affected. If igneous rock can find its way up through the numerous fissures of the earth, surely water can easily find its way down to the central heat. I take it that the breadth of the line I am pointing out lies between the 165th parallel of east longitude and the 170th parallel of west longitude, or, rather, a slight diagonal or curved line across these parallels—south to north.
With respect to the numerous extinct volcanoes about Auckland, I should be glad if some member of the Institute residing in that locality would, before the road-contractors cart away these beautiful little cones to repair the roads—an act of perfect vandalism, I think, which the people of Auckland should at once put a stop to, as these little craters form
one of the-most beautiful pieces of extinct volcanic scenery in the Southern Hemisphere—kindly furnish us with the compass bearings of the mouths of the different craters, in order that we may judge of the wind's direction at the time when they were in activity. In Fiji I think the low side of some of the craters faced the south-east, but I only write from memory. The highest side of a crater is always to leeward of the prevailing wind, owing to the dust and scoria being blown in that direction
Fiji and Samoa are clearly of volcanic origin, but in times so long past that it would be difficult to guess when they were thrown up from the sea. I noticed many extinct craters in Fiji and Samoa, but there are no active ones. There are, however, warm springs in a few places.
The three principal Tongan islands are low, being quite different to the towering majestic hills of the former groups. Tonga appears to me to be the result of one gentle upheaval; yet the Langiis in Tongatabu must have been built cœval with the ruins we find at Stonehenge, Brittany, Central America, and other places. Mr A. W. Mackay kindly gave me two photographs of the trinolith there, which I lay before the meeting. I have always considered the stone images of Easter Island and the trinolith at Tonga came from almost the one and the same people, existing at the time of the pyramid-building age, four to five thousand years ago—a gentle, unwarlike, artistic race, submerged by successive barbarous Asiatic or Malayan colonising expeditions from Japan and Borneo. (“Viti” or “fiji” in Japanese means “a chain of hills”; Mount Fuji is its sacred mountain, I think.) Mr. Mackay promised to send me a paper containing a minute description of the Langiis, which I will lay before members as soon as I get it. The ruins at Ponape and Espiritu Santo, in the New Hebrides—and I think some will be found also in New Caledonia—may have dated from the same time, or they may be of a later construction—perhaps later.
Generally the ruins found in different islands in the Pacific will be found a subject of most interesting study. We find them at Tonga, Espiritu Santo (New Hebrides), Ponape, the Carolines, I think New Caledonia, Easter Island, and I am not certain whether there are not traces of the mound-builders to be met with in the Sandwich Group and Tahiti. It may have been that the Aztecs and Toltecs of Central America and the highly civilised ancient Peruvians sent out their colonising galleys westward into the Pacific four or five thousand year ago, and it is the ruins left by these colonies we find to-day; the Malayan and Negrettic populations we now find in the Pacific being of a later date, and having submerged the old
colonies, just as the Spaniards wiped out that same gentle race.
Neither the ruins at Ponape nor the Langiis at Tongatabu show much alteration in land-levels, so that those that support the theory of a great sunken continent in the Pacific will have to account for this absence of alteration during the past four to five thousand years. I am rather inclined to think, from the volcanic phenomena I am pointing out, that the tendency has been slight upheaval, together with subsidence. Nature appears to me to be so steady in all its physical phenomena that I can find nowhere evidences of great subsidence, or buckling, or even crumpling, in the earth's crust. There is a slight movement I admit, but so slight that it takes years and years for us even to notice it, such as the alteration in land—and I may be allowed to say sea—levels of the east and west coasts of the North and South American, Continent. Directly there is too much subsidence, and the sea-water too readily finds its way to the central lava, immediately that portion of the globe becomes, as it were, a steam-boiler, and the crust is puffed out again into its proper shape, the extra steam escaping through or forming a near volcanic vent.
The whole of the central and eastern islands of the Pacific appear to me to be purely volcanic, for even what we name the “coral islands” are built up by the coral polyp from a volcanic base. What we call “atolls” are only the tops of extinct craters or volcanic hills, subsiding from the result of previous volcanic action. If built on the tops of craters, then the entrances should be in the direction of the prevailing wind, as that would be the lowest point of the crater (perhaps some of the captains of the Union Steamship Company would tell us whether this is so).But this rule would be subject to the varied work of the coral polyp. I only throw the suggestion out now for subsequent observation. The trend of the islands is certainly south-east and north-west, which also is, I think, the direction of the prevailing winds in the South Pacific.
In Samoa there are no permanently active present volcanoes. The group appears to lie almost outside the present line of active volcanic action; it is simply a cluster of extinct volcanoes. During the hurricane of the 26th March, 1883, all the vessels that were in Apia Harbour, except one small schooner, were driven out to sea and lost, this being attributed to a number of heavy waves, caused by earthquake. (To me it appears that the hurricane was the cause of the disaster, and not the earthquake.) Again, on the 12th September, 1866, dense masses Of smoke arose from the sea near Tau Island and Orosenga (sometimes called Olusinga), and continued till the middle of November. The outbreak was pre-
ceded by repeated shocks of earthquake. It is not known whether a shoal has since been formed. The water was previously deep.
Earthquakes occur occasionally in Samoa, but have not caused much damage. On the 16th March, 1889, the great hurricane at Apia wrecked the German warships “Ebor,” “Olga,” “Adler,” and “Nipsic,” and the American ships “Trenton” and “Vadalia,” Captain Kane, in H.M.S. “Calliope,” steaming out in the teeth of the gale. No one attributed this misfortune to an earthquake.
I mention these matters now so as to warn our seamen to up-anchor and away from Apia whenever, in March, the weather looks threatening. Even in January I have experienced the tail end of a hurricane in Apia. January to March are dangerous months in the Pacific.
Aporima, or Apolima, a small volcanic island, and Savaii, rising 5,000 ft., contain many extinct craters.
In Fiji volcanic action has not entirely ceased, but there are no active craters. Violent earthquake shocks are sometimes felt, and at Wainunu and Na Saru Saru on Vanua Levu, and also on the Island of Ngau, there are boiling springs.
Rotumah (latitude 177° 10′ E.) is entirely volcanic, several exhausted craters being found there, but no trace of eruption for many years past; large and old trees growing and flourishing at the mouth of the principal crater. The surface of Rotumah is chiefly covered with scoria and ashes, among which lies a scanty but very productive soil.
The chains of the Ellice, Gilbert, and Marshall Islands, lying between the parallels of longitude included in my table -170° to 180° east longitude—look very volcanic in their origin. So does the semicircle of islands forming the Ladrone Group; also the trend of the islands south-east to north-west from and including the Sandwich Islands. It is much the same with the Caroline Islands, Paumotus, Society Islands, Cook and Austral Groups. The whole of these islands it will be noticed, including New Guinea, the Solomons, New Caledonia, and others, trend to the north-west; so do Java and Sumatra. Many of the atolls and sunken reefs awash trend also south - east to north - west. It is quite remarkable how constant this trending is all through the Pacific Islands.
On the other hand, Japan, the Kurile Islands, Kamchatka, and the Aleutian Islands trend to the north-east, as if in the original cooling of the planet the present ocean-bed of the Pacific set that way. It is as if internal volcanic energy expends itself in opposite directions like atmospheric storms in the Northern and Southern Hemispheres; or
perhaps I had better say as if internal volcanic energy, like the atmosphere, was and is subject to the diurnal revolution of the planet. I think I am justified in saying that it would be so in the original cooling of our earth's crust, and this quite apart from the great work performed by sedimentary deposit in forming the crust.
In a paper contributed to volume ix. of our Transactions I tabulated the formation of the various groups of islands in the Pacific as follows: Volcanic—Bonin Islands, Ladrones, Carolines, Sandwich, Marquesas, Society and Georgian, Cook, Samoan, Tonga, Fiji, New Hebrides, Banks, Santa Cruz, Solomons, New Ireland, and New Britain; coral—Marshall, Gilberts, Paumotus, Phœnix, Union, Loyalty, New Caledonia. But this tabulation was only a rough one, as I pointed out at the time that the Carolines, Cook, and Tonga Islands were of both volcanic and coral formation. Thus the hill at Neafu (Vavau, Tonga), called “Tolau” (from which visitors gaze upon one of the finest harbours in the Pacific, and as beautiful a scene as any one could wish to see), struck me as being formed by a volcanic blow of lava, which, disintegrating in the course of time, gives the present excellent chocolate - coloured soil around it. The coral, too, in the boat-cave at the entrance to the harbour, which visitors should see, is split in all directions by volcanic upheaval. (This cave is situated within a mile of Mariner's Cave, described by Byron.) The Island of Vavau is there-fore both of coral and volcanic formation; indeed, all coral islands may be said to have a volcanic base.
A great number of the low coral islands in the Pacific have a lake in the centre, showing volcanic subsidence, or, rather, upheaval and subsidence, more than anything else. Nor is it very curious, seeing their origin, that these lakes should be composed of mineral water. The lake at White Island (New Zealand) is, I believe, hydrochloric acid. The whole Pacific bed is blistered with volcanoes.
I looked at the lake immediately at the back of Nukualofa (Tonga), and speculated as to the time when it was so formed—far anterior to the date of the Langiis. On the other hand, I have run aground upon an atoll, and wondered whether it was from the top of a crater that the coral polyp had begun its labour or a hill-top only of the supposed great sunken continent. There does not appear to be anything like the volcanic action in the equatorial belts of the Atlantic or Indian Oceans that we find in the Pacific, or we should have far more numerous islands in those oceans; so that, when considering geological questions in the Pacific, we are bound to take into account the terrific volcanic agency always at work. True, there are extinct volcanoes and lava-beds in
England, Scotland, Wales, France, and elsewhere, and basalt columns at Fingal's Cave, in Ireland. (Why basalt - like starch should form into columns is another physical law which we know little about. From my point of view, however, these laws rule, and are governed by a living, as it were, vital energy which I have in previous papers been trying to describe, although, perhaps, not very successfully.)
But terrible as this agency appears to us, nevertheless it has been-gentle in its constructive action—throwing the land up step by step and terrace by terrace; aiding the work of the coral insect here, and slowly lowering their gigantic breakwaters there; building huge mountains by the gradual deposit of lava and ash from below the sea-level to a height of 3,000 ft., 10,000 ft., and even 14,000 ft. above it; floating billions of tons of pumice over the sea and millions of tons of dust through the air; slowly bulging the reefs and islands outwards a few feet at a time, or washing those reefs and islands away by tidal waves and strong sea-currents. But, on the whole, the work has been gentle and comparatively harmless to human life; for what is even a couple of hundred feet of upheaval at the outside of any one spot—which our records give—in comparison with the geographical extent of the Pacific Ocean itself? Moreover, what is going on now has always been going on. The natives reside in perfect security beneath the active volcanoes, and cook their food in the thermal springs.
When I come to my third line of volcanic upheaval it will be noticed how constant a suggested 200 ft. upheaval appears west to east, as if volcanic energy, no longer meeting with the weight of the ocean waters, expends itself 200 ft. at the outside into the atmosphere. For, although Mauna Kea, in Hawaii, towers up some 13,805 ft. above ocean-level, and sinks down 18,000 ft. beneath the sea (3,023 fathoms) at forty-three miles' distance from the shore—a far greater total height than any mountain-range we find upon land—yet, so far as we know, the whole of this mountain has been formed by the deposit of volcanic lava, ash, and débris, showing what a true safety-valve it has been for untold centuries of time. (From this cinder-heap to San Francisco soundings show a level-sea-bottom upon which a railway-line could be laid as upon a billiard-table.)
To any one, too, unacquainted with the great height of the mountains of Hawaii this island might appear of a comparatively small elevation, for its surface rises gradually from the sea fairly uniform; so that even the terrific energy here displayed has formed only a gentle-looking mound 150 miles in diameter at the base arid 32,000 ft. in height, whose pleasant glades supply for mankind some of the most beautiful
home-spots in the world. It was through one of these pleasant grassy homesteads in 1868 that the imprisoned lava burst forth “in four huge fountains, 500 ft. to 1,000 ft. in height, forming a river 200 ft. to 800 ft. broad.” Any segment of the circle formed by this huge crater would, I think, more than include any segment seen by Sir James Hector in his late trip to the islands south of this colony.
I might be allowed to digress here for a moment to call the attention of our engineers to the excellent work of the coral polyp in constructing harbours and breakwaters. There is a reef stretching away from New Caledonia for some hundreds of miles in length; and the reef fringing the Australian Continent to the eastward is some two thousand miles in length. Would it not be possible for us to imitate the work of nature's little polyp engineers, and, with a solution of lime, build away slowly and steadily, bit by bit (not monolith by monolith, as is being done in Napier), and so gradually expose a ragged broken wall to the sea, exactly similar to any of the fringing reefs of the Pacific islands? I must say that to my mind a smooth faced and topped monolithic breakwater is absolutely contrary to nature's breakwaters I have seen on every Bide in the Pacific. The rugged coral breaks up the water, as the huge rollers dash themselves harmlessly on the sea reefs; and on the shore reefs, the branching tree-coral, there built up from slender stems, even the shore surf fails to dislodge, so long as the live polyp inhabits its slender and often most delicate branches. The Napier Breakwater, as at present constructed, to my mind, is therefore quite opposed to nature's teaching. If the engineer-in-charge would take a trip to the Pacific islands he would see breakwaters of stupendous dimensions round almost every island, constructed in the very teeth of the waves, and sp simply that his huge monoliths would appear barbarous and quite out of place. Nor do I know of any coral breakwaters constructed at right angles to the coast-line, as in Napier. Nature always builds her breakwaters a mile more or less from the shore, and parallel with it, leaving beautifully still water between the reef and the shore.
The Ellice, Gilberts, and Marshall Islands are all low coral-islands, earthquakes being occasionally experienced in the Gilberts from a south-west direction. Pleasant Island, in the Gilberts, is about 100 ft. high, haying apparently been raised by volcanic action (latitude 0° 32′ S., longitude 166° 55′ E.). Along this first line, from Auckland to the equator, or perhaps I had better say as a general rule in the Pacific, the south-east trade winds blow steadily from May to November, During the remainder of the year the trade winds are frequently interrupted by northerly and westerly winds. A hurricane
occurs at any time between December and April. It must be noted, too, that great submarine volcanic movements do occur in this vast ocean no observations of which are made or records kept, and, as I have said, the observations made are very conflicting. Sometimes the pumice-stone reaches the surface, and for days vessels have sailed through a sea of it. But more often, in the great depths, the outthrow remains where it has been ejected, and is but slightly affected by ocean currents. From one view of this intricate question a volcano is really a delicate spring-balance. The boiling lava in the great crater of Mauna Loa, at the Sandwich Islands, is kept at its balance by so much sea-water finding its way beneath the earth's solid crust by some crevice within a radius of per-haps five hundred miles, more or less. An extra quantity of water pouring in produces a lava overflow. If the whole ocean-bed upon which the Sandwich Islands stand for a radius of, say, five hundred miles gently crumpled or subsided I do not think the eruptions would be so sudden. Still it will be noted that the lava flowed in 1855 for thirteen months. But even this is too short a period for the subsidence theory as being the cause of volcanic action. Nor do land-levels on the sea-line at the Sandwich Islands show subsidence—at least, I have not heard or read of such. These should show if subsidence was the cause of the many lava outflows there.
My task in this paper, I know, is to record the volcanic phenomena of the Pacific. But it is evident that water pouring in beneath the earth's crust—say, within a thousand miles of the right or left of the 180th parallel of longitude—and being immediately converted into steam, might tend to cause volcanic eruptions, and outputs of purely local lava, ash, or cinder at different rents right along that parallel south of the equator; or the water might pour in immediately at the foot of each particular volcano, which itself has formed the crevices simply by upheaval. (I ask to be allowed to draw a distinction between a fault and a crevice.) In our own great Tara-wera eruption of 1886 a small lake disappeared, I think, immediately before the eruption. In the vast region of the earth's surface now under consideration it may be that earthquakes breed earthquakes and volcanoes multiply volcanoes, for it is evident that the more the earth's crust is broken upwards the more readily will the sea-water find entrance through the faults and crevices. On the great continents the absence of active volcanoes may be accounted for by the fact that only rain-water falls upon their surface, and that this supply is not sufficient at any one fault or crevice to set up thermal energy. Be this as it may, the fact of Mount Erebus, Tarawera, Falcon Island, and Metis throwing out somewhat
different ash and lava is no reason why the whole line should not be affected by one great internal cause. It has been said that an earthquake is only an incompleted volcano, but my view of the matter is slightly different. Shrinkage of the earth's crust (if shrinkage is still going on) would no doubt tend to close up all crevices, and so keep our seas upon the surface; but, nevertheless, the argument is justifiable that volcanoes are delicate steam spring-balances set in or near great water regions only.
Second Line of Activity.
Having said all I wish now to say concerning the first line of volcanic action in the Pacific, running from Mounts Erebus and Terror in latitude 72° S. to the equator on both sides of the 180th parallel of longitude, I will now proceed to the second line of activity, running from, let us say, Hunter Island, near Fiji, to the northern coast of New Guinea. Further than that I do not wish to go, as the doing so would take me into the volcanic phenomena of the Malay Archipelago, which requires a separate paper, and about which I know very little. The almost total absence of volcanic phenomena on the Australian Continent justifies me, I think, in drawing attention to the two lines I have sketched upon the map.
A glance at a map will show what I mean—viz., the line of present activity running from Fearn or Hunter Island on to the New Hebrides, Banks, Santa Cruz, Solomons, New Ireland, New Britain, the Louisade, Admiralty Islands, and New Guinea. New Caledonia, with Australia, appears to be outside this line, as earthquake shocks are very infrequent in both places. I am, however, not well acquainted with the phenomena in New Caledonia, but I hope shortly to pay a visit to that group.
This second, or north-western, line from Hunter Island forms, perhaps, a portion of, and the first or northern line bounding the 180th parallel of longitude evidently joins, a great crevasse belt, as it were, of weakness in the earth's crust, running east from Java to Central and South America, although, of course, I only hazard such a statement for the guidance of other observers. It is, I think, the widest stretch of ocean we have. It has been observed in other parts of the earth that craters in close proximity to each other do not throw out the same substances, but lava and ash from different strata, showing independent local action. But I take it that great thermal action when escaping would only melt the different local strata through which it passes, and yet the steam-force—say, by the incursion of water—be connected heneath the earth's crust. Earthquake phenomena would therefore have to be most carefully collected from the vast
number of islands lying between Tonga and Central and South America before we could venture to affirm that any direct line of weakness existed between Java and South America viâ Tonga; for, although the great Lisbon earthquake of 1755 was felt across the Atlantic, we know of no line of weakness in that direction, except, of course, in the Azores and Canaries. That earthquake was, as it were, a crust disturbance or wave over 700,000 miles of surface. So that lines of volcanic earth rents or fractures may be purely local, yet subject to sympathetic influence from distant disturbances. The question is, Are they so subject? Another matter is whether a number of seisumometic stations established along these three lines I speak of in the Pacific Islands would afford proof of subterranean connection. Perhaps the table of dates I propose to submit at a future date may be of some use in determining this question.
Fearn or Hunter Island lies about 180 miles south-west of Kandavu (Fiji), in longitude 172° 5′ E., latitude 22° 24′ S. It is a volcanic block, about 974 ft. high, half a mile long, aud about one-third of a mile broad. It contains, so I am informed, hundreds of tons of sulphur: jets of sulphurous vapours constantly issue from it. There is anchorage there for a 300-ton or 400-ton vessel. From the Wellington Evening Post shipping news of the 30th December, 1895, I take the following extract:—
“Hunter Island, one of those solitary but slumbering connecting-links of the great volcanic system that stretches from New Zealand right up to the East Indies, has, after three score years of apparent quietude, again burst forth, and given vent to the terrific subterranean forces that of late years have manifested themselves at similarly situated spots in the South Pacific. The captain of the American barque ‘Seminole,’ which lately arrived at Sydney from the Pacific Slope, reports, according to the Sydney News, passing the island in question on the 24th November and witnessing a magnificent spectacle. From two craters on the east side of the island, which at times was enveloped in sulphurous smoke and débris, large streams of lava poured down its mountainous side. The ‘Seminole’ passed within a mile and a half of the spot, but no trace of life could be seen. Hunter Island, however, has never been inhabited within the knowledge of man. It was discovered nearly a century ago, and is situated nearly midway between Norfolk Island and Fiji. At all times for the past ninety years thin smoke has ascended from the various points along its monotonously savage-looking sides. As long ago as 1835 the island burst out and shot forth a huge pillar of flame and molten lava, which ran down its side hissing to the sea. Since then, however, its hidden forces appear to have lain dormant.”
Next we come to the New Hebrides. I first attach a description of what happened at Ambrym lately, as it is well to preserve it:—
“Some of the officers of H.M.S. ‘Dart’ ascended the volcano on Ambrym Island. The crater is a mile wide and 1,000 ft. deep. The stream of lava extends to Dip Point, and a column of steam rises to a height of 4,000 ft. A violent submarine disturbance has been experienced, smoke and fire rising near the south of the mission station. Frequent earthquakes are felt, and the sea as far as Mallieollo Island is covered with dust. Six natives have been killed by falling stones.”
“Further details of the eruption at Ambrym, in the New Hebrides, show that it was one of the most remarkable disturbances recorded in the South Seas. As the flow of molten Lava came on, filling up the valleys in its course towards the sea, the rush and roar became louder and louder, and every now and then, midst the dense smoke caused by the lava setting fire to everything inflammable, would arise a volume of steam as it rushed into the streams. The lava travelled several miles before reaching the sea. It completely swept a cliff away for a width of 30 yards, and poured into the ocean with a tremendous roar and hissing noise. When the glowing mass touched the water an immense volume of steam arose to a height which the officers of H.M.S. ‘Dart’ measured as 4,000 ft., and the sea boiled furiously, so that the man-of-war had to move out of reach. A continual fall of volcanic dust and other débris is still going on, and is completely covering everything. It is feared the natives will be reduced to starvation by the destruction of the crops. Should the fall continue much longer, all the vegetation will be killed from its effects. During the night shock after shock of earthquake occurred, some very violent, causing a sickly sensation amongst the ‘Dart's’ crew. From Port Sandwich, twelve miles distant, Ambrym looks like an island covered with snow. When the eruption began the natives were terror-stricken, men, women, and children fleeing for their lives.”
“Admiral Bowden-Smith has received the following details of the eruption at the New Hebrides Group from the commander of H.M.S. ‘Dart’: On the 16th October, 1894 [he writes], whilst lying at Dip Point, Ambrym Island, an eruption on that island took place. On weighing anchor at 6 a.m. and proceeding to the eastward to resume surveying Work, a remarkable heavy mass of cloud was seen rising over the centre of the island, and, on clearing the point, dense columns of smoke were seen descending from just the other side of the low coastal range. It presently became evident
that a lava stream, marked by dense columns of smoke, was making its way through the hills to the sea. The ship was-Stopped some 300 yards off the shore, where it was seen that the stream would emerge, and at 8 a.m. bursts of flames were seen rising among the trees, and presently the head of the stream appeared, a red-hot molten mass, with lumps of slag tossing about on the surface. When it reached the water a most magnificent sight ensued. A dense pillar of steam rose rapidly in a perpendicular direction to a height which was afterwards found to be 4,500 ft. A few seconds later violent submarine explosions of steam took place, the water rising in huge bubbles some 100 ft. high, and then bursting in all directions in radiating tongues of water with black masses of presumably lava. A considerable swell was set up outwards, and, as the area of explosions appeared to be extending rapidly, the ship was moved to a safer distance. Canoes full of natives were leaving the island in all directions, some of which were taken in tow to Dip Point, where they were clear of immediate danger. The ship then proceeded round to the south side of the island, when it was seen that the old crater at Mount Marum, in the centre of the island, was in violent eruption, and then dense masses of smoke were rising over the western end of the island. On returning, whilst rounding Dip Point, a sudden outburst, accompanied by continued violent explosions, took place. About two miles to the southward of the mission station the cliffs were seen to be falling in landslips, and, when anchoring, flames appeared over the crest of the gap behind the mission. The natives were assembled in terrified groups on the beach, and I accordingly sent the boats in, offering to take off all that wished. The group was in a state of tremor, and the noise of the eruption indescribable. Dust and débris from the burning bush fell continuously. We embarked over eighty men, women, and children, for the most part belonging to Dr. Lamb's mission, and proceeded with them to Rannon, near the north-east point of the island, a place of comparative safety. Through the next day the earthquake shocks were so severe as to cause the resident trader, Mr. Rossi, a Frenchman, to remove to Port Sandwich with all his natives and belongings. The natives brought from Dip Point were comfortably housed in a schoolhouse belonging to Dr. Lamb. The next morning (17th October) we proceeded to the northeast point of the island as far as Dip Point which was found to be in inky darkness, objects scarcely visible over a quarter of a mile. Communicated with the shore, and found the natives reassured, as the actual fires had ceased. At 6 p.m. we proceeded to Port Sandwich, not clearing the shower of dust till more than half-way across. Several shocks were experienced
on the way, and at night thirty-one shocks were distinctly-felt in seven hours forty minutes on board the ship, one at half-past 2 a.m. being particularly severe. At 7 a.m. on the 18th October we returned to Ambrym, dust still falling. A great portion of the cliff at Dip Point had fallen in the sea, and all along the shore to the eastward continuous clouds of dust were rising, and landslips occurred. We anchored at Rannon on the 20th October, and re-embarked all the natives, and landed them at Dip Point, all present danger being removed. Dust was falling heavier than ever, but of a lighter colour and finer description. Everything on shore was covered with a deposit of from ½ in. to ¾ in., the landscape being of one uniform dull slate-colour, and the ship was shortly a grey mass. Landed and proceeded over the hills until the lava stream was reached. Although cooled down, it was still proceeding at some 4 ft. or 5 ft. an hour in the direction of Banlag, on the south-east. Owing, however, to the thickness of the atmosphere, it was impossible to get any views of what was happening. Proceeded at 3 p.m. to Port Sandwich.”
Port Sandwich must not be confused with Sandwich Island, or Vate, in the New Hebrides, as Ambrym Island is only twelve miles from Port Sandwich.
I might here refer to the Rev. A. W. Murray's visit to Ambrym, in the “John Williams,” in September, 1861. He says, “There is an active volcano in the interior of the island, with the smoke of which the mountains in the neighbourhood are more or less enveloped. We were afterwards told by traders that the volcano is not on the island itself, but on a small island close to it—so close that seen from the opposite side it seemed part of the mainland.”
Tanna is 320 miles south of Ambrym, showing the wide range of volcanic action in this one remarkable group.
The order of the most important islands in the New Hebrides Group, south to north, is as follows: Aneiteum, Tanna (containing Port Resolution), and Futuna, then Erromango, Sandwich Island (containing Vila Harbour and Havannah Harbour), Api, Mallicollo (containing Sandwich Harbour), Ambrym, Pentecost or Whitsuntide Island, St. Bartholomew, Espiritu Santo, Lepers, and Aurora Island.
Having taken Ambrym first, I will finish it. Ambrym Island really occupies a position north of centre in the group (latitude 16° 20′ S., longitude 168° 17′ E.). The island rises abruptly from the sea, extending some seventeen miles north and south by twenty-two miles east and west. Its hills are densely covered with vegetation. The height of Mount Marum, which is generally an active volcano, is 3,500 ft., and of Mount Tuiyo, on the northern end of the island,
3,100 ft. As seen from the north-west the latter has a beautiful and imposing appearance, from its symmetrical shape and the luxuriant vegetation on its lower slopes. The volcano on Mount Marum has no visible cone, but apparently an enormous crater. It occupies the centre of the island, standing in the middle of vast rugged fields of lava hitherto unapproachable. Round the main mass of the volcano are numerous recent cones no longer active, and covered with forest. In 1888 this volcano was unusually active, and in the following year three new craters were reported to exist in the centre of the island, and numerous jets of smoke were observed on the eastern coast and at Dip Point. It may be that volcanic activity has been greater than ordinary during the past twenty-five years. Visitors from America and Europe desirous of seeing some of these remarkable volcanoes should time their departure for New Zealand so as to arrive here about April or May. The hurricane season is then over, and also the hot summer months. The Union Company's steamers would carry them on to the different groups of islands, or tranship them to other steamers. Dip Point is on the west side of Ambrym, and rises abruptly from a small sandy beach to a height of about 20G ft. It appears to be formed of compressed volcanic sand and ashes in layers. A few miles southeast of Dip Point, in Belbin Bay, there are some hot springs. Black sand is usually found all round these islands.
Next, as to Tanna. This is what Captain Cook says of this volcano (his visit occurred in 1774):—
“Having found that the light we had seen in the night was occasioned by a volcano, which we observed to throw up vast quantities of fire and smoke, with a rumbling noise heard at a distance, we now made sail for the island, and presently after discovered a small inlet, which had the appearance of being a good harbour. The volcano, which was about four miles to the west of us, vomited up vast quantities of fire and smoke; and the flames were seen during the night to rise above the hill which lay between us and it. At every eruption it made a long rumbling noise like that of thunder, or the blowing-up of large mines. A heavy shower of rain, which fell at this time, seemed to increase it; and, the wind blowing from the same quarter, the air was loaded with its ashes, which fell so thick that everything was covered with the dust. It was a kind of fine sand or stone, ground or burnt to powder, and was exceedingly troublesome to the eyes. During the whole of the 11th the volcano was exceedingly troublesome and made a terrible noise, throwing up prodigious columns of fire and smoke at each explosion, which happened at every three or four minutes; and at one time great stones were seen high in the air. Forster and his party went up the hill on
the west side of the harbour, where he found three places from whence smoke of a sulphurous smell issued through cracks or fissures in the earth. The ground about these was exceedingly hot and parched or burnt, and they seemed to keep pace with the volcano, for at every explosion of the latter the quantity of smoke or steam in these was greatly-increased, and forced out so as to rise in small columns, which we saw from the ship, and had taken for common fires made by the natives. A thermometer placed in a little hole made in one of them rose from 80°—at which it stood in the open air—to 170°. Several other parts of the hill emitted smoke or steam all the day, and the volcano was unusually furious, insomuch that the air was loaded with its ashes. The rain-which fell at this time was a compound of water, sand, and earth; so that it properly might be called showers of mire. Whichever way the wind was, we were plagued with the ashes; unless it blew very strong indeed- from the opposite, direction.”
The longitude of Tanna is 169° 20′ E., and the latitude 19° 30′ S. In August, 1840, the Rev. J. Turner visited the New Hebrides, but was driven away by the natives. That missionary shortly afterwards sent a report to the directors of-the London Missionary Society, which contains the following reference:—
“Port Resolution (named by Cook after his own vessel), or Nea, Tanna, opens to the north, and is formed by a neck of low land on the east side, abounding in pumice-stone and other volcanic matter, and on the west by a mountain 500 ft. above the level of the sea. The interior of the mountain is a vast furnace, and in some places the crust is so thin that on-passing over it it is like walking on a hot iron plate. Near the top of this mountain there is a barren spot, with fissure here and there, from which volumes of steam burst up now and then, and also sulphurous vapours. The greater part of the mountain, however, is covered with vegetation, and is inhabited by a population of some five hundred people, scattered about in several villages. They have not the slightest apprehension of danger, and have their settlements so arranged as to throw some of the hot places into their Marum, or forum, for public meetings, in the very centre of the village. There they lounge and enjoy themselves, on a cold day, from the underground heat, and there, too, they have their night dances. Around the base of this mountain, and among the rocks on-the west side of the harbour, there are several hot springs, which are of great service to the natives. Their degrees of heat vary. Some form a pleasant tepid bath, and to these the sick resort, especially those suffering from ulcerous sores. Some rise to 190°, and others bubble up about the boiling-
point. Every day you may see the women there cooking their yams and other vegetables, in hollow places dug out, and which form a series of never-failing boiling-pots. The men and boys have only to stand on the rocks, spear their fish, and pitch them into the. hob spring.* Beyond this mountain, and about five miles from the anchorage, stands the cone of the volcano. The black sandy dust and cinders from the crater form a barren valley about a mile wide all round the base of the mountain which forms the crater. In crossing the valley one day we felt our walking-sticks going down among something soft, and, on looking round, found it to be a beautiful bed of sulphur, yellow as gold. Not far from the same place the fumes of sulphur were so strong from some fissures that, we could not go near them. Near the base of the mountain we found some masses of a clayey substance, hard and in some places burning hot. From cracks here and there the steam and boiling water came up as from an immense boiler. But what most astonished us at this place was a steady drop, drop, dropping of water, quite cold, and clear as crystal, from a fissure within a few feet of another crack which was sending forth a blast of air so hot that we could not bear the hand near it for two seconds. It is the same at the hot springs already referred to. You can boil yams at one place, and within 5 yards of it get a glass of cool fresh water. The ascent up the mountain to the edge of the cup is a gradual slope, but the walking is laborious, as you sink to the ankles at every step in the fine dark-grey dust or sand which has accumulated from the eruptions of the volcano. The perpendicular height of the crater from the valley at its base is almost 300 ft. When you reach the edge of the cup you see that it is oblong and curved rather than circular, and about a mile and a half in circumference. On reaching the top and looking over the edge you expect to see the boiling lava, but instead of that the great cup contains five other smaller cups or outlets, separated from each other by ridges of dark sand. To see the boiling lava you would require to go down inside the outer cup, and then up one of these interior ridges. Were it solid rock the attempt might be made, but from the fragile sandy appearance of these smaller ridges it seems as if it would be sure to slip, and down you go. Then, again, you never know the moment there is to be an eruption, nor do you know from which of the five outlets it is to come. I felt no
[Footnote] * We could almost fancy that Mr. Turner was writing upon the phenomena and the custom of the natives of our own hot-lakes district in New Zealand. So near to each other are the Now Hebrides and New Zealand, so similar are the phenomena, that I think Mr. McKay must admit some connection in the line of volcanic strength.
inclination to risk the experiment, which would be something like examining the interior of the mouth of a cannon, not knowing the instant it might go off. You feel that you are far enough when you stand on the edge of the outer cup. The hissing, panting, blowing, and strange unearthly sounds from these great gulfs, as you look down and along, are fearful, and presently you are awe-struck with the thundering deafening roar of an eruption, which baffles description. The simultaneous bursting of a number of steam engine boilers, or the explosion of a ton of gunpowder, or the united volley from a regiment or two of infantry and artillery might be something like it. Then up fly the great crimson flakes of liquid lava, which gradually blacken and consolidate, and descend. More solid blocks of stone fly up with these softer masses, and rise far above them to a height of 200 ft. and 300 ft. from the edge of the cup. The most of this matter falls right down again into the crater. It sometimes takes a slant, however, as you see from the masses of obsidian or volcanic glass and scoria all about, so that you require to have your wits about you, keep a look-out overhead, and be ready to ‘stand from under.’ Clouds of steam and thick black smoke also rise with every eruption. This smoke goes, of course, with the prevailing wind, and the atmosphere for miles in that direction is charged with the dark volcanic dust. The volcano was to the west of where we lived. The first day we had a westerly wind Mr. Nisbet and I were busy out-of-doors putting up the roof of our house. We felt a strange sensation about the eyes and nostrils, and could not imagine what it was which was gathering on our hands and arms. Presently we discovered that the clouds of black dust from the volcano were coming in our direction, and that the atmosphere was loaded with the finest dark-grey particles. Next morning every leaf and blade of grass was covered with a thin coating of something like the finest steel filings. Our people were in the habit of praying to their gods for a change of wind on such occasions, and that, we were told, was pretty much the case all over the island. Every one, when annoyed with the smoke and dust, prays that they may be sent elsewhere. At Port Resolution we seldom had a westerly wind, and, as it did not last above a day or two, we did not suffer much inconvenience from the volcano; but that dust must be very troublesome to settlements in a westerly direction. Captain Cook speaks of having been annoyed by this volcanic dust. He did not venture so far inland as to visit the volcano. The account, however, which he recorded of the frequency of the eruptions, and their appearance from the harbour, is interesting and useful, as it is an exact description of the working of the volcano at the present day. Speaking of the mountain on the west side of
the bay, to which we have referred, he thus wrote: ‘Some of our gentlemen attempted to ascend a hill at some distance, with an intent of observing the volcano more distinctly, but they were obliged to retreat precipitately, the ground under them being so not that they might as well have walked over an oven. The smell, too, of the air was intolerably sulphurous, which was occasioned by a smoke that issued from the fissures of the earth.’ In another place he remarks, ‘On Thursday, the 11th, during the night, the volcano was very troublesome, and threw out great quantities of fire and smoke, with a most tremendous noise; and sometimes we saw great stones thrown into the air. On the 12th the volcano was more furious than ever, and we were much molested with the ashes’ (‘Cook's Voyages,’ folio edition, p. 168). Had we been longer on the island we might probably have paid a night visit to the volcano; but it was a fine sight to look over from our door, on a calm clear evening, to the brilliant display of fireworks, which went blazing up every eight or ten minutes. So far as we observed, that is the usual interval between the eruptions night and day. The native name of the volcano is Asur (Yasua). They have a tradition that it came from the neighbouring island of Aneiteum; and probably this may be founded on some fact, as the extinction of a volcano on Aneiteum being followed by the outbreak of this one on Tanna.”
Aneiteum is certainly volcanic, and rises some 2,700 ft. above sea-level. It is only a few miles from Tanna. Earthquakes are frequent. On the 28th March, 1875, a severe shock was felt, accompanied by a seismic wave, since which date the volcano at Tanna has been unusually active. Aneiteum is the most southern island of the New Hebridean group. The kauri-pine grows here, as well as at Kandavu, in Fiji. This island is slightly nearer New Zealand than Kandavu. Aneiteum, Kandavu, and Auckland form what I may call the “triangle” of the kauri-pine; a problem I leave to botanists.
The Island of Futuna, to the east of Tanna, rises up out of the sea like a great square table some 2,000 ft. high. The missionary estimates of these heights are not exact. I regret to say that neither the heights of the mountains nor the circumferences of the islands in the early missionary accounts can be depended upon. They have often deceived me. Otherwise the accounts are excellent and most praiseworthy.
I wish to mention here that in May, 1845, Mr. Turner visited Lifu (Loyalty Islands, not so very far from Tanna), which he describes as “being probably eighty miles in circumference, an uplifted coral formation, and covered with pines in some places. The highest land on the island may be 300 ft. above the level of the sea.” Of Mare he says, “Mare is a
smaller island than Lifu. It, too, is a mass of uplifted coral. There are marks of two distinct upheavings.”
In July, 1848, Mr. Turner was again at Tanna, but he makes no mention of the activity of the volcano then.
In October, 1887, the volcano at Tanna (Mount Yasua) was unusually active, the eruptions being heard many miles distant, and the smoke and ash reaching to the Island of Erromango, lying to the north. About the same time an eruption resembling the explosion of a torpedo was seen in Sandwich Harbour, Mallicollo—320 miles away—where a severe shock of earthquake was also felt. (I have referred above to a somewhat similar explosion at Niu-afu, mentioned by Mr. Tarvis as having occurred in August, 1886. These explosions are merely the old plug of the crater being blown out, like a cannon ball, by the new explosion.)
Sandwich Harbour, in Mallicollo, must not be confused with Vila Harbour, in Sandwich Island, or Efate. Havannah Harbour is also in Efate, or Vate. This is the finest island, and the headquarters of trade in the group. Steamers regularly call now at Vila.
The more southern islands of this group rise steeply from the sea to a height of 500 ft. to 1,000 ft., when in many cases there is a plateau, and again a rise of 500 ft. to 1,000 ft.
The volcano at Tanna has two distinct craters. It is destitute of vegetation, and is situated in the south-eastern part of the island, eight miles from Port Resolution. Its height was ascertained by the officers of H.M.S. “Pearl,” with aneroid barometer, to be 980 ft., the crater being about 600 ft. in diameter and 300 ft. deep. During a part of the time of the “Pearl's” visit it was throwing up large masses of scoria to a height of 600 ft. There is a large lake, a mile in length, near the foot of the mountain. Port Resolution is situated at the eastern end of the island. On the 10th January and on the 11th February, 1878, earthquakes occurred here. Previous to the outbreaks the wind had been strong and variable, and the weather hot, with rain; the volcano throwing up huge rocks. Within the recollection of the natives no earthquake had occurred before. At the first earthquake a new volcano burst out close to Sulphur Bay, between it and the old volcano. A wave about 50 ft. high arose, swept the eastern point of the harbour, and destroyed the native plantations, vast numbers of fish being left in the bush by the receding water. About 100 yards of the bed or bottom of the harbour at the west side rose above the former sea-level.*
[Footnote] * It will be remembered how, during the great earthquake of 1855 in Wellington, the bottom of the harbour was similarly raised about 4ft. So that I may say volcanic upheaval keeps the crust of the earth fairly at its proper contour where there is danger of much subsidence. It appears to me to be a wonderful force most gently guided. That it is principally thermal can be seen from the regularity of the steam pulsations both in Captain Cook's and the Rev. Mr. Turner's accounts. So that the volcanoes we possess not only keep the oceans on the surface of the earth, but the crust of the earth itself “true to shape.” I therefore cannot follow Sir B. S. Ball's argument of the absorption of the oceans by the planet in the short period he names.
another 300 yards of the bottom was thrown upward, making the entrance to the harbour very narrow. Across the harbour, a little inside the entrance, there is now a bar, with only 15 ft. of water, where formerly there was a depth of 5 to 5 ½ fathoms. In some, places near the shore the bottom has been raised 20 ft., or even more, above the sea. The whole harbour is so contracted by the upheaval that it is doubtful if a large vessel could find room to swing in it. At about a cable seaward from the west point of the entrance three rocks have been thrown up in a position where formerly there was 11 fathoms (66 ft.) of water. A high hill near the rock named Cook's Pyramid, on the west side of the entrance, fell into the sea. This made a new point of land; and Cook's Pyramid has been raised about 40ft. A patch of discoloured water, about a cable in extent—probably a shoal formed by the earthquakes—has since been seen about two miles north of the port. H.M.S. “Nelson,” however, obtained a sounding of 116 fathoms nearly in this position. On the west side of the island the shock was scarcely felt, and there was no seismic wave. From information supplied by the British Consul at Noumea it appears that in August, 1878, about a fortnight after H.M. schooner “Renard” had completed a resurvey of Port Resolution, rendered necessary by these volcanic upheavals, another earthquake and extensive upheaval took place. Cook's Pyramid disappeared, its remains being made out with difficulty; and though the harbour has narrowed to about 200 yards, and the depth decreased considerably, there is still good anchorage for small vessels in it, and fairly good shelter from south-east winds for large vessels off the entrance. On the 28th March, 1875, an earthquake and seismic wave visited Dillon Bay, Erromango. The wave rolled large boulders of rock on to the beach, and altered the depth and direction of the entrance to the river, which has since silted up. The foreshore and most of the terraces of Erromango consist chiefly of coral limestone, showing considerable symptoms of upheaval, with here and there a black volcanic rock.
I should consider Mai, or Three Hills, Island, rising respectively 1,850 ft., 1,450 ft., and 1,400 ft., and Api (Tasiko) Island, with its three peaks, rising respectively 2,500 ft.,
2,800 ft., and 1,800 ft., formed by gradual volcanic action, and perhaps' upheaval.
The Island of Lopevi, about three miles east of Paama, also contains an active volcano, occasionally throwing out burning ashes. It is a perfect cone, rising some 5,000 ft. out of the sea.
Lepers Island, or Omla, was so named probably in consequence of the prevalent skin-disease being mistaken for leprosy. It is about seventeen miles long, north-east and south-west: Its magnificent mountain/rising to a height of 4,000ft., resembles a whale's back in outline, and from the sea assumes a most imposing appearance. On its summit is a small lake, from the centre of which rises a small crater that of ten emits smoke.
Port Sandwich, on Mallicollo Island, is said to be the only harbour in this group where a moderate-sized vessel could ride out a hurricane in safety. At Pentecost Island, and at numerous islands in the Pacific, beds of the streams often change suddenly and most remarkably after heavy rains. In 1873 I pulled my boat through living cocoanut-trees standing fairly deep in the water up Nandi River, in Fiji. That stream had just previously changed its bed. In Tonga, of course, there are no rivers or streams. I suppose the loose soil in all volcanic islands accounts for this sudden alteration.
Near Cape Cumberland, forming the north point of the great Island of Espiritu Santo—sixty-four miles long and thirty-four broad—“are to be seen the ruins of buildings of considerable size, pillars of regular shape and fragments of masonry scattered over a plain of about three miles in extent; and at a village five miles distant from the cape are similar remains, of which the natives appear profoundly ignorant.” I mention these ruins as they may be useful in determining land-levels in this direction; but the ruins are doubtless only broken pillars of basalt.
Cape Quiros, the opposite horn of St. Philip's Bay, runs back in successive steps towards the central range of Espiritu Santo. These steps may doubtless give the height of the successive upheavals.
Generally, with regard to the north-west line I am now following through the Western Pacific, in the Admiralty sailing directions are the following remarks: “A great number of the islands are entirely of volcanic origin, many attaining a high elevation, arid at the present time they include several active volcanoes. Lesson Island, off the north-east: coast of New Guinea; the volcanoes in the north-eastern portion of New Britain and in the Duportail Islands; Bagana, in Bpugainville Island, of the Solomon Group; Tinakula, in the Santa Cruz Group; and Tanna and Ambrym, in the
New Hebrides, have all been recently: in eruption. As a consequence of this volcanic activity great fields of pumice have been seen by various navigators, covering large tracts of the Western Pacific to such an extent that ships have been occupied for days in sailing through them; and subsequent to the eruption in New Britain in 1878 fields of this material were floating about amongst the islands for many months, reaching as far to the eastward as the Ellice Group. Earthquakes are of frequent occurrence in the vicinity of New Britain and the Solomon Islands, though, as a rule, they are of moderate character; while in the southern islands of the New Hebrides Group they sometimes occur. Some slight shocks have been recently (1887) reported from the north-east coast of New Guinea, during which the atmosphere is described as being so thick as to give the appearance of dense rain. In 1878 severe shocks of earthquake were experienced over a large area. At Port Resolution, in the Island of Tanna, two shocks occurred, whereby the port as a harbour for large vessels was partially destroyed; and in the neighbourhood of Lord Howe Islands the barque ‘Pacific Slope’ reports having felt a shock on the 3rd March, the vessel at the same time being set by an unusual current 110 miles to the south-south-east.”
I am much indebted to the Admiralty directions for many such extracts in this paper. I consider it well to collect them into one paper, add the remarks of other observers, and include my own observations, in order not only that we may have the whole of the most important earthquake volcanic phenomena of the Pacific before us in the one paper, but also that we may know where to establish seismic stations.
I hope in a future paper to give a list of dates as a record of what is happening at the present day.
With respect to Banks Islands and Santa Cruz, the Banks Islands are all of volcanic origin—Gana (Santa Maria Island), Vanua Levu, Ureparapara (Bligh Island), Valua (Saddle Island), Mota (Sugar-loaf Island), and Merlav (Star Peak Island). Mota and Merlav “rise straight up from considerable depths to well-defined symmetrical cones 1,350 ft. to 2,900 ft, high. Ureparapara is simply the unsubmerged portion of a large crater with the eastern face blown out, forming a fine harbour therein.” Vanua Lava, Gana, and Ureparapara still exhibit signs of latent activity in the form of fumaroles and sulphur springs. Merlav has long been inactive as a volcano. Mota exhibits distinct signs of upheaval, the volcanic portion of the island resting on a base of madrepore (fossil coral). The summit of the volcanic range running through Vanua Levu frequently emits columns of steam. The sulphur springs, fumaroles, and solfataras are on the west side of the Gana
Lake, which is eighteen miles in circumference, with a black-sand bottom, and 400 ft. to 500 ft. above sea-level. Mota, as is well known, is the headquarters of the Melanesian Mission in the Banks Group. Volcanic heat is still felt on the western slope of the summit of the old crater at Ureparapara; extreme height, 2,440 ft.
The Santa Cruz Group lies to the north of the Banks Group, and consists of six larger islands, namely: Vanikbro (where La Perouse's crew were wrecked and massacred in 1788), Terai, Ndeni (Santa Cruz), Te Motu, Tinakula, Lord Howe* Island,† and the Swallow Group of smaller islands, (At Nukapu, in the Swallows, Bishop Patteson was killed in 1871; and Commodore Goodenough, whom I well remember, was killed at Carlisle Bay, in the Island of Santa Cruz, in 1875.) In both these groups—Santa Cruz and Banks—shoals and little islands appear and disappear from time to time, showing the wonderful volcanic agency at work.
Tinakula, or Volcano Island (Tamami), lies twenty-seven miles to the north-west of Ndeni Island, and is a volcanic cone rising to the height of 2,200 ft. The lower portion is covered with vegetation; the upper part is entirely barren. In 1871 H.M.S. “Rosario” observed a stream of lava flowing down the north-north-west side of the cone. Flames and smoke were also emitted at intervals of from ten to fifteen minutes. In 1886 H.M.S. “Opal” visited Tinakula, and the volcano was described as having recently been active.
With regard to the Solomons, “Some of these islands are entirely volcanic, whilst others are calcareous, but there are also many in which both formations are combined. Guadalcanar is volcanic (latitude 9° 45′ S., longitude 160° E.), and so is Saro. The volcanic character of Saro does not appear to be generally known. The last eruption seems to have occurred thirty-five or forty years since, when large quantities of water, dust, and ashes were ejected, and several natives killed. Although at the present time the volcanic forces are slumbering the natives are always apprehensive of an outbreak. Earthquakes are very frequent, and during one, which occurred several years ago a subsidence of part of the coast took place, and vessels now anchor where there was a village. Buraku (Murray Island) is a volcanic island 1,000 ft. high; uninhabited. The Maroro Group (New Georgia) consists of three principal and innumerable small islands. The larger islands are of recent volcanic origin, and have numerous symmetrical cones (latitude 8° 50′ S., longitude 158° 13′ E.). Rendova
[Footnote] * As the Pacific becomes better known this reduplication of names should be done away with; it is very confusing.
[Footnote] † This island must not be confused with the Lord Howe Island off New South Wales.
Island is volcanic, rising 2,500 ft. In Vella Island many of the peaks contain dormant volcanoes. Narovo Island is about, four miles long. With the exception of the adjacent Islet of Simlo, and the harrow neck, which are of upraised coral, the whole of this island is of volcanic formation, signs of activity being at present confined to the southern portion, which contains the more elevated land, and Middle Hill and South Hill, rising to a height of 1,000 ft. and 1,100 ft. respectively. On the south-west coast, at the foot of the north slope of the crater (South Hill), there is a salt-water lagoon which communicates with the sea on its north side. On the south shore of this lagoon is a boiling spring, and in the vicinity the water is hot for about 30 yards from the shore. The lagoon is frequented by crocodiles; proving its former connection with New Guinea, and perhaps Australia.
Fauro Island is volcanic, rising 1,925 ft. Bougainville, the largest of the Solomon Islands, is about 110 miles long and thirty broad. The southern part of this island is very mountainous, the summits ranging from 4,000 ft. to 10,000 ft. Amongst these are several volcanic cones, but only one—-Bagona, in the centre of the island—is at present in a state of active eruption. This volcano forms a conspicuous object for passing vessels, being visible for more than fifty miles. At the back of Empress Augusta Bay, on the west side of the island, a volcano has been seen in full activity.
Of the isolated islands near the Solomons, as I have before remarked, the British barque “Pacific Slope” reported having experienced a shock caused by volcanic eruption in the neighbourhood of Lord Howe Islands on the 3rd March, 1878, and to have been set 110 miles south-south-east by an unusual current. A great quantity of pumice-stone was afterwards found floating around the ship.
With regard to New Britain, from a report contributed by the Rev. William Fletcher to the Fiji Times of January, 1876 (which I find in my scrap-book), of the manner in which the Wesleyan Mission was opened in the Duke of York, New-Britain, and New Ireland groups of islands, in the schooner “Wesley,” by the Rev. G. Brown and himself, during July-and August of the previous year, I make the following extracts: “The islets about Duke of York Island are formed” by coral upheaval. There are two lofty volcanic peaks (the-Mother and Two Daughters) in New Britain (longitude 152° E.). Simpson Bay (New Britain) is a noble harbour, but the whole aspect of the hills surrounding it suggests terrible volcanic agency. As to these peaks—the Mother, 2,470 ft. high; the Northern Daughter, 1,866 ft.; and Southern Daughter, 1,727 ft.—-the top of the last is a large bare crater, its volcanic fires so lately extinguished that vegetation has not had time to
clothe its sides. Some of the natives said that smoke still issued from the top; others that there was a lake at the bottom of the crater. At night there was a strong and offensive smell of sulphur. Earthquakes, accompanied with loud roarings and undulatory motions of the earth, are also said to be common. Henderson Island is composed of volcanic ash and gravel, and is of very recent formation (so the old men say), having been thrown up during ah earthquake. On landing we found a late subsidence of the beach, and in one place we saw extensive landslips, caused by earthquake. There appeared to be few fringing reefs about the Solomon Islands or in this locality. The great depth of water close to the islands and the scarcity of good anchorage we often noticed.”
Besides what I have already quoted from the Rev. W. Fletcher's report, the Admiralty sailing directions give as follows: “The island (New Britain) generally is mountainous, and in the northern peninsula there is an active volcano, which was last in violent eruption in February, 1878: At that time an island—Volcano Island—60 ft. to 70 ft. in height was thrown up on the western shore of Blanche Bay. This eruption was succeeded by a seismic wave, which washed away a large portion of Matupi Island and the whole of Blanche Bay and St. George Channel was covered with pumice. In the north-west portion of the island, south of the Gazelle Peninsula, and in the Duportail Islands, off this part of the coast, there are also active volcanoes.”
Blanche Bay is overlooked by the three magnificent cones of the Mother and North and South Daughters, on Crater Peninsula, with the rugged outlines of the smaller volcanoes in the foreground. The Germans have established a coal and trading station at Greet Harbour, on this peninsula, between Sulphur and Bridges Point, so that I should think deposits of sulphur will be found there.
On the 13th March, 1888—not so very long before the great shock in the Amuri district, recorded by Mr. McKay in volume xxi. of our Transactions, to which I have already referred, and during the time the booming noises were being heard in that district—Greet Harbour “was visited by a seismic wave, reports of which have been received from other parts of the coast of New Britain, as well as from the northeast coast of New Guinea. At Matupi Island, fronting the harbour, the sea receded at times from 12 ft. to 15 ft. below the lowest water-mark, and then rose in several waves to the same height above high-water mark; but this phenomenon was chiefly confined to the north and south-east sides of the island. The waves came partly from the south and partly from west-north-west. No indications of earthquake were
noticed. The weather at the time was clear, with a gentle south-east breeze.”
About one mile north of Bridges Point is a hot salt-water creek.
On the mainland of New Britain, abreast the Duportail Islands, are the North Son, Father, and South Son Mountains, which attain respectively heights of about 1,300 ft., 4,000 ft., and 3,000 ft. The former is apparently an extinct volcano; the two latter are still active.
Leaving New Britain, and travelling on further west and north, we come to Rook Island, of volcanic origin, the highest of whose mountain-peaks reaches 5,000 ft. Volcano Island, off the north-east point of Book Island, is in latitude 5° 32′ S., longitude 148° 6′ E. Its form is that of a regular cone, broken at the summit, about 3,500 ft. high. In March, 1700, Dampier described this island as being in active eruption. Lottin Island—not far from Volcano Island—is also a volcanic cone, 5,200 ft. high, from which smoke issues from a large hollow on the north-east side. North Island is about thirty miles further north. In November, 1861, Captain Lass, of the brig “Wailua,” discovered a singular shoal five miles north-west of it. The shoal is about half a mile, wide and five miles long, in the form of a crescent. Captain Lass reported that on approaching the shoal an appearance was observed as of a whale spouting, which was found to be a boiling spring, emitting water to a height which he estimated at 150 ft. A boat was lowered, and a sounding of 10 ft. was obtained on the shoal.
About fifteen miles to the northward of North Island lies Gipps Island, a round sugar-loaf-shaped island about three miles in circumference. The island is thickly populated. There is a boiling spring on a sandy beach on the south-east side, and also one on the south-west side, which threw up water at times to a height of 20 ft.
Near the south-west end of the largest of the Duportail Islands, lying sixty miles to the eastward of New Britain, there is an active volcano.
With regard to the D'Entrecasteaux group of islands, at Seymour Bay, Ferguson Island, on the south-west coast, there are saline lakes and several small hills giving forth sulphur fumes, and there are also several boiling springs.
Germany having lately named the harbours and rivers upon the north coast of New Guinea differently from those upon the map, I can but refer now to the seismic phenomena I have gathered in that direction for subsequent verification.
Starting from Cape King William, passing Astrolabe Bay, and following the coast-line of New Guinea in a north-westerly direction, we come to Vulcan Island, of which I attach a
sketch taken from the New Zealand Graphic (Plate LI.). “Vulcan Island is considered to be one of the largest volcanoes in the Pacific, if not in the whole world.” The crater of Kilaueanui (near Honolulu) is the largest crater we know of. Vulcan Island is in latitude 4° 5′ S., longitude 145° 2′ E., and is only about 4,000 ft. high, whereas Cotopaxi is 18,887ft. The island is clothed with vegetation. Hecla, in Iceland, and Jan Meyen (70° 49′N.) are also larger.
On the 13th March, 1888, Hatzfeldt Harbour was visited by a seismic wave, which also visited Gape Bang William and the coasts of New Britain. “Soon after 6 a.m. a noise like firing was heard to the north and north-east, and at 6.40 a wave, coming from the former direction, broke upon the shore at a height of 6 ½ft. above high-water mark; it then receded with such violence that half the port was dry. About 8 a.m. the height of the wave was from 23 ft to 26 ft. The sea continued to rise and fall at intervals of three to four minutes until 9 a.m., when it began gradually to subside, and by 6 p.m. it had resumed its normal condition.”
With respect to the sound caused by earth-movements, the sound waves of the Tarawera eruption in New Zealand on the 10th June, 1886, travelled a radius of a hundred and fifty-miles—viz., beyond Auckland and Wellington—giving a whole diameter of three hundred miles. I heard the sound of the explosion near Wellington much like the distant muffled discharge of heavy ordnance. A booming sound usually precedes a Sharp earth-shock. This is caused by the peculiar sonorosity which sound takes when confined in the earth. Drop a pin down a well, and, if it strikes the water flatly, the sound wave set up will be most sharp and distinct. It cannot be otherwise, seing that the sound waves, in place of spreading, are confined by the circumference of the well, and can only travel upwards. Now, if a pin will do this, what are we to expect from an earth-wave itself grinding and rending the solid earth strata?
When the great earthquake of Cosequina, in Nicaragua, took place, in 1835, the subterranean noise—-the sonorous waves of the earth—was heard at a distance of a thousand miles; whilst in the eruptions of the volcano on the Island of St. Vincent, in 1812, at 2 a.m. a noise like the report of cannon was heard, without any sensible concussion of the earth, over a space of 160,000 geographical square miles. There have also been heard subterranean thunderings for two years without earthquakes. I think Mr. McKay told us that such rumblings were heard for a year previous to the late sharp earthquake on the Hanmer Plains. A friend informs me that the late Mr. Cooper, native interpreter, of Gladstone, Wairarapa, told him that he was sleeping
in a Native village near Tarawera on the night of the great eruption of 1886. Some three hours before the outbreak the whare suddenly swarmed with rats, and the natives were as surprised as himself at the invasion. No doubt the rats had heard the subterranean rumbling, and thought it advisable to get away from danger, for had they remained they would most certainly have been killed or buried. From this it has been proposed to foretell earthquakes by connecting telephones to the pipes of deep artesian wells and to metal plates sunk in deep mountain crevices. Any unusual noise in the bowels of the earth would be audible in the telephone, and would indicate trouble.
As I write, too—April, 1895—the volcano Cotopaxi, in Ecuador, is active, and the inhabitants of Quito are terror stricken.
The whole of Southern Austria and Northern Italy, too, has: just been—18th April, 1895—-much shaken by thirty-one shocks of an extensive earthquake, many cities being panics striken (Laylach, Venice, Trieste, &c.), and railways so twisted as to be unworkable. These shocks were accompanied by incessant roars of the most terrifying description. At a hundred and fifty miles distance such roars would, I think, somewhat resemble the discharge of cannon.
With respect to tidal waves, I wish to point out to the people, inhabiting the islands of the Pacific the recurrence of the wave in Hatzfeldt Harbour, New Guinea, varying from 1 ft. above high-water mark to 25 ft.; also, the time of the disturbance—viz., twelve hours. As seismic phenomena are frequent in the Pacific, I should advise the people there to look as carefully as they can after their boats and shipping, and to remove themselves and their valuable belongings for twenty-four hours to high ground when any island is visited by what is called a tidal: wave, as there is no trusting the damage such an unwelcome visitor may do. Water, when moving forward in a body—for waves do not usually move—has almost as much power as water falling in a body. It will toss upon its crest huge rocks of many tons weight, and tear up and level down almost any obstruction in its path. A tidal wave in an hour will do more damage to an island than a century of storm, hurricane, and rain.
At Victoria Bay, D'Urville Island (New Guinea)—not marked on the map—there is a salt thermal spring on the south side of the bay, the temperature of which approaches boiling-point.
Lesson Island, the southernmost of the Schouten Isle Group, is an active volcano, about 3,000 ft. high. Trees and grass reach almost to the top on the northern side; but on the southern side, nearly the whole distance to the base, the
island has a burnt red appearance, showing the devastation caused by a late eruption. Garhot Island, in the same groups, is also a steep cone, but not so steep as Lesson Island; and Blosseville Island is a high, steep, wooded crater, remarkable for several large villages upon its edge. The natives evidently have far more confidence in the safety of these craters than I have.
As I write these notes—22nd March, 1895—a series of earthquakes are reported by telegram as having been felt at Port Moresby and other parts of New Guinea on the 6th and 7th of March last. The first shock lasted three minutes. No damage was done, but the natives were in great consternation. It is surmised that an extinct volcano on the island had opened up. Oh the 18th April, 1895, a telegram by way of Sydney states that a tidal wave in New Guinea has swept away many houses and drowned one child in a native village there. Both telegrams, I should think, refer to the one earth-movement. (I do not name volcanic phenomena “catastrophies,” although I am very sorry when loss of life occurs, even to a little native child. I regard these earth-movements as absolutely essential to the welfare of the planet.)