116 The Earthquake Wave. 



Art. XIX. — On the Earthquake Wave of the loth August, 



1868. 



[Read by the President, R. L. J. Ellery, Esq., 29th October, 1868.] 



The President gave a brief account of the unusual waves 

 which were experienced on the shores of some of the Pacific 

 islands, New Zealand, and Australia, on the 15th of August 

 last,* which he stated were undoubtedly the result of the 

 frightful earthquakes which occurred along the west coast of 

 South America on the 13th August. He had obtained the 

 local times of the occurrence of the waves at Apia, or 

 Charlotte Island, of Gilbert's Group in the North Pacific ; at 

 Lyttletou, New Zealand ; at Sydney, Adelaide, and King 

 George's Sound. The waves had been experienced at many 

 other places, but he had not got the times with sufficient 

 precision to make any use of them to obtain the rate at which 

 the sea disturbances must have travelled. The waves at 

 King George's Sound — the most westerly point at which 

 they were noted — were weak but " notable." At Adelaide 

 they were unmistakably remarked at 7 a.m., 10 a.m., 

 and again at 4 p.m. At Sydney the tide gauge showed 

 the first disturbance at 2.30 a.m. on the 15th, but the 

 greatest effect took place five hours later. At Newcastle 

 7.24 a.m. it swung the ships at anchor around, and washed 

 boats on shore. In New Zealand and Chatham Islands the 

 wave rose from four to eight feet, doing considerable damage 

 on the low-lying coasts. In Savaii, in the Navigators 

 Islands, it rose fifteen feet on the east side, while at Apia 

 much further north and east, it rose as high as eight feet. 



From intelligence last received from Callao, it appeared 

 that climax of the earthquake took place there at about 

 5.15 p.m. local time, although further south it did not 

 happen till 9 p.m. Assuming the time at Callao, therefore, 

 as 5.15 p.m. on the 13th, the corresponding Greenwich time 

 would be about 10.19 p.m. on the 13th. The times of 

 occurrence of the waves at the various points, as well as 

 their approximate distances • from Callao, were given as 

 follows : — 



