Old Fallacies and New Facts About Earthquakes.

H. F. Baird.

In an address to the Canterbury Branch of the Royal Society, Mr. H. F. Baird outlined briefly our present knowledge on earthquakes, earthquake destruction, and popular fallacies. The speaker said that if those who were in possession of the faces—the learned societies, the professions concerned, architects, engineers, builders, physicists, and geologists, and the better informed local bodies—would realise their duty to the people, the earthquake menace could be practically overcome. If they impressed on the people that prudent and far-sighted planning was necessary by constructing earthquake resisting buildings, then material damage would be reduced. This policy, together with advice for behaviour during earthquakes, would diminish greatly the number of fatalities. Persistence was necessary, however, as the time that elapsed between local destructive shocks was sufficient in most cases to allow a feeling of security to grow. The attitude of mind—“It can't happen here”—-must be counteracted, and buildings properly constructed if the next destructive earthquake is not to be a disaster. Moreover, if those professions combined with seismological observatories, properly equipped with modern instruments, vital problems could be attacked, concerning fault lines and block movements, and perhaps give the general location of future seismic activity.

Mr. Baird then discussed some fallacies, commonly held concerning earthquakes. The advice to leave a building during severe shocks is a notable one. Apart from the physical difficulty during the height of the motion, it has been shown that over 90 per cent, of the fatalities occur through people being struck by falling debris as they leave the buildings. The best places are under arches, doorways, tables, where falling material can do least harm. Other fallacies concerned luminous phenomena, waves in solid material, earthquake weather, and earthquake prediction.

Mr. Baird then passed on to the types of elastic wave which traverse the earth, modern views of the interior of the earth, the distribution of earthquake zones and their connection with mountain systems and their geological age, volcanic areas past and present, and continental shelves. He concluded by showing slides of the effects of major earthquakes of this country.