November 11, 1922 Tsunami: Northern Chile

1922, November 10, 23:53 [local time]. There was a very strong earthquake in the southern part of Atacama province, with a zone of destruction approximately from Copiapo to Coquimbo. The instrumental and macroseismic epicenters were fixed at sea in the region of Vallenar - Huasco. This tsunami generating earthquake began with relatively weak, but comparatively rapidly intensifying oscillations, lasting from 1/2 to 8 minutes according to different estimates. The earthquake was preceded by strong foreschocks, felt on the 3rd and 7th of November. Seismic activity in the focal zone of the earthquake was high for two months.

At Chanaral, the tsunami began an hour after the earthquake and lasted about 4 hours. The sea surged onshore three times. It rose 9 m above the high tide mark, destroyed 14 homes, and carried four homes inland (there was no destruction resulting directly from the earthquake here). The tides were calm, but prolonged.

At Caldera the sea at first remained completely calm after the earthquake, but then it rose: 15 minutes, 30 minutes, or 45 minutes after the earthquake, according to different estimates. The most reliable in this respect, is the report of a witness, who at the time of the earthquake was on a ship riding in the harbor, and who set off for the port in a boat immediately after the strong shocks had ceased. When the boat arrived at shore 15 minutes later, the water had risen about 5 m above the high tide level and almost splashed over the moorage.

At Coquimbo, the sea was absolutely quiet before the earthquake. About 2 hours after the earthquake, a tsunami appeared. The waves spread from the northeast to the southwest along the axis of the bay, passed along the western and eastern shores, but did not cause any damage. On the south shore, the water rose to a considerable height. Three large tidal waves were observed, the third being the most destructive. The water penetrated 2 km at the most low-lying places, and the rise was 5 m above the maximum high tide line or 6 m above the mean sea level. It reached 7 m above mean sea level at the railway quay. The water rose and fell slowly; the ebb was smaller than the flood; the surface of the water was calm. As a result, the part of the city situated at the southern apex of the Bay was totally destroyed, not alone by the water, but also by boats and other objects which it carried.

Several hundred people drowned in the waves.

The tsunami was also observed at Huasco, Antofasgasta, Callao, San Felix and San Ambrosio Islands. The tsunami arrived at San Diego, CA, 13 hours after the earthquake and at San Francisco, CA, 13.8 hours after the earthquake. The tsunami arrived at Hilo, HI, in 14.5 hours. The tsunami arrived at Apia (Samoa Islands) in 14.1 hours. At Pago Pago on Tutuila Island the period of oscillations was 20 minutes. The tsunami was also observed in Japan, Taiwan, New Zealand, Australia, and the Philippines.

(above from reference #415)