August 23, 1872 Earthquake: Fox Islands, Aleutian Islands, Alaska, United States

This is the first instrumentally located earthquake and tsunami source.

A wide variety of sources was suggested by early investigators for the August 1872 tsunami, but Cox (Reference #65) determined from the difference in the tsunami arrival times at San Francisco and Honolulu that it originated on the Pacific shelf and slope of the eastern Aleutian Islands. The marigraphic evidence of its arrival at St. Paul island permitted the time and location of its origin to be identified with greater certainty and precision than was possible earlier.

Assuming the initial feature of the tsunami propagating southeastward to have been a crest, as considered most likely, its most probable origin time was estimated at about 18:06 UTC on 23 August, and the most probable position of the center of its origin area was estimated at about 52.2N, 168.5W. If the initial feature propagating southeastward was a trough, the origin time was most probably about 18:00 UTC, and the center of the origin area was most probably about 53.3N, 166.4W.

The range of possible origin times is considered no greater than about 25 minutes (17:55 to 18:20 UTC). The range of possible longitudes of the center of the origin area is no greater than about 7o (164oW to 171oW); the range of latitudes is no greater than about 3o (51o to 54oN).

(above from Reference #1623)

Reference #542 lists 52N, 172W

Reference #237 lists 52.2N, 166.4W.