EARTHQUAKES OF MAY 19 60 IN CHILE — SAINT-AMAND 347 



been between Puerto Saavedra and Bahia Mansa (fig. 2). The height 

 at which the wave arrived depended greatly on the configuration of the 

 sea coast. 



The maremoto was observed at Cumberland on the island of Mas a 

 Tierra in the Juan Fernandez group, located some 480 km. west of 

 Valparaiso. There, it began as a lowering of the sea, at about 4 :15 

 p.m., local time, followed in about 10 minutes by a rise of li/^ m. 

 The sea oscillated several times, doing essentially no damage. Cum- 

 berland Bay is sheltered somewhat by the island, and so the portion of 

 the wave received was, in part, only a diffracted wave ; however, the 

 island rises abruptly from the deep and has essentially no sloping 

 submarine platform. Hence, it can be said that the actual sea wave 

 at this distance was more than 2 m. in amplitude. 



On the Isla Mocha (fig. 1) the maremoto began as a withdrawal of 

 the sea (so it was reported) . However, the shaking there was so fierce, 

 with cows, horses, and people falling to the ground, that it is quite 

 possible that no one noticed the first movements of the water. The sea 

 seemed to "stand still, backing up against itself, the water boiling as 

 it withdrew." Wlien it returned, it reached at least 1/2 km. inland on 

 the eastern shore, destroying the government radio station and the 

 docks and scattering the remains of a two-story fieldstone building 

 located 500 m. from the shore some 200 m. up the gentle slope. As the 

 sea withdrew, it clawed grooves out of the grass, exposing the shell- 

 rich soil beneath in parallel furrows 1 m. wide and 20 m. long. A 

 private pilot, hunting on the island, had left his plane parked on the 

 beach. Feeling the lurching of the earthquake, he realized what was 

 going to happen, and ran to his plane. Starting the motor, he raced, 

 without waiting to warm the engine, into a frantic takeoff; but, just as 

 the plane became airborne, a wave reached it. The plane was carried 

 to some trees where the quick-witted pilot leaped from the craft to 

 cling to a tree. The plane was carried out to sea. 



Damage to vegetation from tlie tsunami was also noted on the west- 

 ern shore, and, although no detailed observations were made there, 

 the waves did not seem to reach as high as on the eastern shore. 



A very readable account of the maremoto, written by Captain 

 Andrade[l] ^ of the Chilean Navy Hydrographic Office, details the 

 effects of the maremoto all along the coast. A more recent manuscript 

 by Sievers, at the same office, gives more complete information. 



ERUPTION OF VOLCAN PUYEHUE 



At 2 :45 p.m. on May 24 tlie crew of a U.S. Air Force plane, return- 

 ing to Santiago from Puerto Montt, piloted by Col. William R. Cal- 

 houn, USAF, noticed that an explosion was taking place on the side of 



2 Numbers in brackets refer to the list of references at end of article. 



