Ashburton Guardian Magna est Veritas et Prævalebit. MONDAY, APRIL 7, 1930. LAND OF EARTHQUAKES.

Ashburton Guardian, Volume 50, Issue 150, 7 April 1930, Page 4

Ashburton Guardian Magna est Veritas et Prævalebit. MONDAY, APRIL 7, 1930. LAND OF EARTHQUAKES.

The fact that, the inhabitants of certain districts in Japan are alarmed at tire continuance of seismic movements shows that the disturbances are of unusual severity, for Japan is pre-emin-ently the .land of earthquakes. The islands are arranged in the form of a festoon with its convexity facing the Pacific Ocean, and, as in similar groups of islands, the convex side of the festoon slopes more steeply than the concave side. Where there is .tih-e greatest bending, it is there that sudden yielding is the most frequent. The Japan Sea on the western side of Japan is only sixteen hundred fathoms deep, but the Pacific Ocean on the eastern sfde is over four thousand fathoms deep within one hundred miles of the shore. Thus the sea bed on the eastern coast is subjected to a great pressure whicli tends to push at the base of Japan in a sea to land direction. Japan is inclining to topple over, as it. were, into the Pacific Ocean as the submarine pressures are exerted at its base. Apparently there is a constant movement going on and the northern part of Japan has the most frequent earthquakes, but they are not so destructive than the less frequent ones in southern Japan. Various authorities are responsible for the statement that Japan, in some part or other, suffers an earthquake every five hours. In Tokio alone, which is on the border line of the two great 'earthquake districts, and which is the most disturbed region in the country, there are roughly fifty appreciable earthquakes in a year, that is, one each week. The eastern coast is subjected to thfe most disturbances, for, from a record kept over twenty-one years, it has been found that for every strong earthquake originating on the concave Japan Sea side of the islands, there were sixteen on the convex Pacific side. Many of the Japanese earthquakes are extremely violent. In the historic Tokio and Yokohama earthquake of 1923 the floor of Sagami Bay, on which'the two cities are built, sank from seventy \to one hundred fathoms, while its coast rose from three feet to sixteen feet. There were one hundred and seven after-shocks recorded. With the advance in seismological science, of which the Japanese take full advantage, it is possible to predict with some confidence large ’quakes and volcanic eruptions. One dramatic examnle of the value of seismograph stations is shown by the incident when, by Government authority, an island sheltering thirty thousand people was warned of an approaching eruption. The population was removed, and three days later a volcanic outbreak destroyed every buildingon the island.