M 8.3 - Kuril Islands

Tectonic Summary

The November 15, 2006, M 8.3 Kuril Islands earthquake occurred as the result of thrust faulting on the boundary between the Pacific plate and the Okhotsk microplate (part of the broader North America plate). At the location of the earthquake, the Pacific plate moves northwest relative to the Okhotsk microplate at a velocity of about 90 mm/yr. The Pacific plate subducts beneath the Okhotsk microplate at the Kuril Trench and becomes progressively deeper to the northwest, remaining seismically active to a depth of 680 km. The November 15th mainshock occurred at shallow depth within about 80 km of the trench axis.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Thrust-faulting events of the size of the November 15, 2006, earthquake are typically about 230x90 km (length x width); modeling of this earthquake implies dimensions of about 260x80 km, predominantly up-dip and to the northeast of the hypocenter.

The November 15th earthquake is the largest earthquake to have occurred in the central Kuril Islands since the early 20th century. A central Kuril Islands earthquake in 1915 is estimated to have had a magnitude of about 8. The central Kuril Islands commonly experiences one or more events of M 6+ in a decade. To the southwest, the southern Kuril Islands chain experienced a M 8.5 earthquake in 1963. To the northeast, a M 9 earthquake occurred offshore of Kamchatka in 1952. No damage or casualties have been recoreded in association with these earthquakes.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)