EXPERTS DIFFER

New Zealand Times, Volume XLIII, Issue 9868, 14 January 1918, Page 2

EXPERTS DIFFER

SUN-STORMS & EARTHQUAKES THE GOVERNMENT SEISMOLOGIST ON THE SUBJECT. The attention of the Government Seismologist, Mr George Itcgben, having been called to certain statements made by Mr Clement \Vraggo in an interview with a reporter of the “New Zealand Herald, ’’ Mr Hogben remarks as follows: — The possibility of the influence of the sun and moon or or meteorological enauges as Motors in causing earyltquaiies has been fuUy discussed oy seismologists of every school of thought m many countries. Alter the most caronil examination of all the records (including those of many thousands of oarthQuaxes), they iiave como to the conclusion, practically, that if any of the things referred to have any weight at all (which many regard as very doubtful) that weight is extremely small; this applies even to differences of tidal attraction and of barometric pressure. la particular, as regards the variations in the amount of heat received from tho sun in. different years and seasons, Professor 0. G. Knott sums up the case thus: “It is hardly possible to credit the solar radiation with any direct influence: for, as we learnt long ago irom the measurements by Forbes of underground temperature, solar radiation penetrates a very short distance into the earth’s crust.” (Physics of Earthquake Phenomena, p. 129.) I may observe that the earth movements givipg riso to seismic vibrations generally takcplace at a depth of from 15 to 25 miles below the surface, far beyond the reach of any changes in surface temperature. It would bo very misleading to attempt to draw any conclusions or make predictions from tho coincidences of particular earthquakes with solar events. The number of earthquakes recorded every year is very large—about 15.000—50 that, if X were to prophesy an earthquake somwhere on any day whatever taken at random, the chance would bo about forty to one that I should be right. Even the number of large earthquakes in any year is not ' small, so that coincidences would bo bound to appear; and, if we took a few of these as substantial arguments, we could prove almost any theory of tho cause of earthquake. The Wairarana earthquake of August 6th, 1917, proceeded from an origin to the east-south-east, beneath the Pacific Ocean; there have been many shocks from tho same region (probably a band of parallel fault-planes), recorded during the last fifty or sixty years, including tho shock of February 17th, 1863, and that of August 9th, 1904, and at least twenty during the last four or five years. As the nearest part of the disturbed region is about 200 miles from the New Zealand coast, even nervous people may sleep quietly in their beds,, without fear of any serious damage from this, .the most important probably of tbe seismic origins in of near New Zealand. I find myself unable to attach any scientific moaning to the picturesque statement that “in consequence of the change of wireless wave lengths from the sun—like- altering the geag of a motor-car —which are bound to operate after 1920. conditions will become more favourable for seismic and volcanic action,” and so on.