SEISMIC PROPHETS.

Hawera & Normanby Star, Volume XLII, Issue XLII, 28 April 1922, Page 8

SEISMIC PROPHETS.

EARTHQUAKES CAN BE FORE-

TOLD,

RECENT SCIENTIFIC DISCOVERIES.

By the combination of three recent discoveries, each of which, in itself, is not of great importance to the man outside scientific circles, Dr. Andrew C. Lawson, professor of geology at the University of California, has made an astounding discovery. He has found a method whereby the time and place of earthquakes anywhere on the globe may be forecast with the same accuracy as changes in the weather are now forecast. While there is no known method of preventing an earthquake, no matter how far in advance the world may be advised of its coming, nevertheless, such prediction, accurate as to time and place, would, if made public, save thousands of lives by enabling the people to leave the threatened zone, and millions of dollars in property, by enabling the people to prepare to .combat coni??igra.tions, which usually follow disastrous seismic disturbances. Forecasts of earthquakes will not be made public, according to Dr. Lawson, for the main reason that scientists would not dare to reveal their discoveries of coming seismic disturbances. "Suppose we predicted an earthquake, and, by some chance, it failed to arrive on schedule," said Professor Lawson. "'Then the people would form a vigilance committee and come up and lynch us. Suppose, on the other hand, a lot of nervous, impressionable people visualised a great catastrophe from one of our predictions; then we would have a reign of terror. No, we would not dare to tell the world what our instruments are recording. It is safer in our own keeping." The most interesting feature of this great cumulative discovery is that the i coming earthquake is made to tell on itself. In other words, the surprise element, the unexpectedness of its approach, is taken from the temblor, and the date and place where it will strike can be foretold months, possibly approximately years, ahead of the actual arrival, for the coming of the earthquake, unlike thaU of the hurricane, the typhoon, or the cyclone, is a long-continued affair. The final rebound which breaks the crust of the earth and sends vast areas slipping this way and that, is approached slowly, and by degrees which can be studied, charted, photographed, diagrammed, and tabulated. The work of preparing the data on which earthquake forecasts are based is a great deal more arduous and much more delicate tHan the forecasting of storms, or other changes in climatic conditions, but it follows as regular lines as. do weather forecasts, and its bases are so obvious that the great wonder is that man has not discovered them before. The three original discoveries on which Dr. Lawson bases his announcement of the forecasting of earthquakes are as Tollows: —

1. That the crust of the earth is

constantly moving, usually northward, at the rate of a few feet each year.

The motion is known as "strain creep," and is due to the fact that the earth does not run true on its axis-; that is to say, the North Pole, in rotating, creates a 60-foot circle, instead of running on a centre, as does a shaft in its bearings. This wobbling about of the pole causes the creep in the earth's crust.

2. That when this strain creep has created a certain tension, reached a certain limit of stretch, in other words, in the material of which the earth's crust is composed, that material—that is, the crust—gives way at its weakest point, known to geologists as a "rift,'' or "fault," and there is an earthquake. 3. That the rate of strain creep of the earth's crust, the composition of that crust, and the breaking limit— that is, tension point—of the materials composing that crust, which differ greatly in different localities, all can be ascertained with accuracy. Taking these three factors, Dr. Law-so-i's own discoveries, the scientist very sf> mi saw that he had the earthquake c lered where it had to tell on itself. X :'.h the rate of strain creep, and the a; mnt of strain the crust of the globe wi ! endure before breaking, the geologist is able to figure exactly how long the crust of the earth will endure that strain before the "elastic rebound" sets in "and the crusfi breaks. It has ]?«en known, fcr- ySars llihl the latitudes of" many supposedly "fixed" points on the surface of the earth are changing, gradually moving northward. The only way the exact position of these, or any other points on the earth's surface can be fixed, of course, is by astronomical observation and calculation.

Dr. Lawson discovered, however, that the "creep" of the earth's crust is going on all the time, that it is, antecedent to, as well as consequent of, earthquakes. Therefore, like the flow of a river, the flow of ihis mass of earth and stone ever to the northward can be measured. Sometimes such a flow is much accelerated by the "elastic rebound," known to th£ layman as an earthquake. For example, Mount Tamlpais, a peak some 2000 feet high, northward across the Golden Gate from San Francisco, moved 3.04 metres i (approximately 10 feet) in a northwesterly direction from 1854 to 1906, due to strain creep. In 1906, in a few seconds of the earthquake of April of that year, it slipped back" 1.9? metres, rather more than half its 52-year creep, but, in a south-easterly direction, not in hne with its previous advance. The lighthouse on the larger Farallon Island, of San Francisco, was found to have crept 2.06 metres (about six and one-half feet) north-westward between 1860 and 1905, and then, in the earthquake of 1906, to have slipped back 1.29 metres, but this time almost due west of its new position. In other words the whole of the Farallon Island, and probably all the islands of the group, made these two movements. Chaparral, another point of observation moved almost as far during the brief neriod of earthquake in 1906 as it had by stram creep in the 50 years preced"ig. The movement hy creep from 1856 1 n 1906 was 2.61 metres at Chaparral, nd the movement back, in a southwesterly direction by elastic rebound, in 1906, was 2.06 metres. Other places, •'Jid whole groups of places, moved similarly, but in varying directions. 1< rom all these movements and the data concerning them order has been worked, and the figures tabulated, furnishing the basis for the calculation of the time and place of other similar elastic rebounds should any appear in that section