October 6, 1883

The morning of October 6, 1883 started off with an eruption of Mt Augustine volcano, where the north flank of the volcano collapsed into Cook Inlet. This debris entering the inlet caused a tsunami that entered English Bay, 85 km to the east.

Four waves came ashore of English Bay between 8 and 9pm, according to a daily log of the Alaska Commercial Company. Sea Level rose to possibly 9 meters above mean se level. The tsunami occured at low tide, which kept damage low. Ash from Mt Augustine fell on the bay soon after the tsunami arrival.

200 km away from Mt Augustine, on Kodiak, the tsunami was recorded at the tide guage.

During an eruption of the Mount St. Augustine volcano in 1883 a portion of the volcano collapsed into the shallow water of Cook Inlet. A numerical model is used to calculate a tsunami generated by the debris from the volcano collapse. The source of debris is located on the eastern side of the volcano.

Figure 1 depicts maximum tsunami amplitudes (in cm) in the Cook Inlet. The largest tsunami amplitude occur in the of Seldovia-English Bay region.

Fig. 2 describes tsunami travel times in minutes from Mount St. Augustine for impact of a debris avalanche at the eastern shore of Augustine Island.