THE UNSTABLE EARTH.

Manawatu Herald, Volume XXXI, Issue 449, 28 January 1909, Page 2

THE UNSTABLE EARTH.

The cause of the Messina earthquake, says a writer in the Sydney Morning Herald, is perhaps better known than that of any other. That part of Italy has been moving more or less continuously for three years, and moved at frequent intervals before that. Parallel to the Italian coast, somewhere in the Hue from Vesuvius to Etna, and curving round to Sicilly there is said to be a fault in the earth’s surface. The earthquake was the shifting up or down, of one side or the other of this long crack. There are forces that play with the surface of the earth as a man might handle an india-rubber ball, and occasionally the. earth cracks, as the ball may do, and nearly always in a curved line. As to what these forces are there is a good deal of dispute. .The surface of the earth is continually grating up and down. Professor Milne estimates that some 30,000 small earthquakes took place every year, “If we had records we might readily estimate the tirae_ when this activity would,, cease. When this ceases surface denundation will be unopposed. Bit by bit land areas will be reduced- to sea level, and the habitable surfaces, as we now see them, will; be no more.” 'the noise heard when an earthquake takes j place isattdbuted to the grating of two edges of the fault near the surface. Along some of the earthquake flaws in the world’s surface, there is a continual regular movement, corresponding with

night and day, or the tides, supposed to be caused by the extra weight of air and water which is above one side of the flaw at one time, and absent during the other. Professor Milne has made the astonishing discovery that at ordinary times the surface of the earth moves. Two valleys in the Isle of Wight, in which he conducted investigations, were found to behave like flowers, opening when the sun was shining, and closing at night ; that is to say, the heights were closer to each other during the the night than during the day. Professor Milne puts this down to the collection in the valley bed at night of an immense weight of water sucked in by vegetation. Apparently the stability of the earth, which is the ultimate basis of our daily lives, is not absolute.