08/06/1788 | 1788 Shumagin Earthquake


Assumed to be the direct successor of the 1788 Kodiak Island Earthquake, the rupture continued westwards with a small magnitude than the earthquake from July 21st. Even though the evidence is more limited, statigraphic records (Engelhart et al., 2018) and historic reports (Sykes et al., 1981) hint towards a 300km long rupture, which can be associated to a Mw 8.3-8.4 earthquake.

Events in the same region
Date Title Region Preferred Magnitude Quality*
1788 Jul 21st 1788 Kodiak Island Earthquake Alaska 8.6 C
1788 Aug 06th 1788 Shumagin Earthquake Alaska 8.3 C
  • Engelhart et al. (2018) -Engelhart, S., Witter, R., Briggs, R., Dura, T., Koehler, R., Vane, C., ... & Haeussler, P. (2018, April). Historical and stratigraphic evidence for two ruptures of the Alaska-Aleutian megathrust in 1788. In EGU General Assembly Conference Abstracts (p. 9826). - Link
  • NGDC - - Link
Event Characteristics
Preferred Magnitude 8.30 (8.00-8.40)
Epicenter 55.000°N, -161.000°E
Depth unknown
Tsunami yes
Paleo-Event no
Quality of Evidence C

Magnitude Range
Year Reference Magnitude
2018 Engelhart et al. (2018) 8.3 (8.3-8.4)
2010 NGDC 8

This table lists some of the most relevant publications in estimating the moment magnitude of this earthquake. If you think there are other important or new publications, please get in contact.