A desastrous earthquake occurred in southern Chile at 22 th, 19 : 11 (GMT), May, 1960, the center of which was located by the Coast and Geodetic Survey, U. S. A. at 38° S, 73 1/2 W. Its magnitude is determined as 8.75 by the Matsushiro Observatory. The shock was felt by persons as far distance as 1000 km. to the north in Chile.
The earthquake and accompanying tsunamis killed 909 of Chilean people and damaged the cities of Concepcion, Valdivia, Puerto Montt, Ancudo etc. It caused crustal deformation along the Chilean coast between 37° to 42° S in latitude. The region around Lebu, Isla Mocha in the north and that around Isla Guafo in the south were upheaved about one meter, while the region between these two subsided about two meters at most. The tsunami originated along and, off the coast of subsided area where big waves assaulted three times with the hight of as large as 10 m and the last one was the highest, while the northern coast than Lebu was visited by far weak tsunami attaining only 1-2 meters in height.
It travelled over the Pacific to Hawaii killing 61 persons at Hilo, and to Japan killing 119 persons.
The energy of the tsunami was estimated as the order of 2 × 1023 erg. It is about the same quantity with that of the Kamchatka Earthquake of 1952. One of the reason why it brought such a large damage to Japan is that the tsunami wave which once diverged itself from the origin again converged near Japan owing to the spherical surface of the globe.
The first phase of the tsunami reached along the coast of Iapan 22 hours later than the occurrence of the earthquake. But the arrival of the largest delayed 1-2 hours more. Its height (double amplitude) attained 5 meters at Hachinohe. It destroyed heavily these villages as Kiritappu in Hokkaido, Ofunato and Shizugawa in Tohoku District, and Ago Bay in Kinki District.
