October 6, 1883 Tsunami: Cook Inlet, AK, United States

Reference #239:

October 6, 1883. This eruption of Saint Augustine Volcano, producing a reported ashfall of up to 5 inches, was accompanied by a series of tsunamis. The first wave may have been produced by the effect of the air wave from the eruption on the water, while the tsunami was the result of a debris avalanche from the collapse of the north face of the peak. An eyewitness account of the volcanic tsunami produced by the eruption was recorded in the daily log of the Alaska Commercial Company trading post at English Bay(Alaska Commercial Company, 1883): "At this morning at 8:15 o'dock, 4 tidal waves flowed with a westerly current, one following the other at the rate of 30 miles p. hour into the shore, the sea rising 20 feet aboye the usual level." Augustine Island, a nearly circular volcanic island that has had six significant eruptions in historical times, is surrounded by underwater deposits similar to that produced by this slide; tsunamis were probably generated repeatedly by this volcano in prehistorical times. It is possible that there may have been Aleut casualties during this event (a search for five or six Aleut hunters camped on Augustine Island just prior to the eruption yielded nothing) but the descriptions are unclear; the death designation here is conjectural.

The tsunami was apparently generated by a debris avalanche from the collapse of the north face of the peak. The slide consisted of about 325 million cubic yards of material moving down from a peak height of 4,100 feet and over a distance of about 5 1/2 miles including 1 mile of newly created land at Burr Point and 1.5 miles further underwater.

Note: Augustine Island is also mentioned as Chernoburyi Island, its Russian name, and variations of this spelling [such as Chernobur, Chernobour, Chernaboura, and Tchernvbura, from reference #2099].