The 1963 Kuril Islands earthquake occurred at 05:17 UTC, on October 13. The earthquake had a magnitude of 8.5 and was followed by a 7.8 event seven days later. Both earthquakes triggered tsunamis that were observed around the northern part of the Pacific Ocean.

Tectonic setting

The Kuril Islands form part of the island arc formed above the subduction zone, where the Pacific plate is being subducted beneath the North American plate. This convergent boundary has been the site of many large megathrust earthquakes, including the second largest earthquake ever recorded.

Damage

No damage, deaths, or injuries were recorded for these two earthquakes or their associated tsunamis.

Characteristics

Earthquake

The earthquake was made up of three sub events, each of which is interpreted to represent the rupture of an asperity roughly 50 km in length along the subduction interface.

Tsunami

The tsunami triggered by the earthquake of October 13, caused a 4.5 m wave locally. The tsunami was also observed in Canada, Japan, Mexico, Hawaii, Alaska, California, and on many islands across the northern Pacific Ocean. The tsunami associated with the October 20 event was larger in the nearby area, with a maximum recorded run-up of 15 m at Urup, but was only observed in the western part of the northern Pacific.