The United States Geological Survey recorded a Magnitude 7.8 Earthquake at a depth of 19.5 km off the east coast of the Kamchatka Peninsula in the Russian Far East slightly before 2.00 am local time on Friday 19 September 2025 (slightly before 7.00 pm on Thursday 18 September, GMT). Despite the size of this event, no casualties have been reported, although tsunami warnings were triggered across the Pacific. The event is thought to have been an aftershock of a Magnitude 8.8 Earthquake recorded off the coast of the Kamchatka Peninsula in July this year.
The Kamchatka Peninsula lies on the eastern edge of the Okhotsk Plate, close to its margin with the Pacific and North American Plates. The Pacific Plate is being subducted along the margin, and as it does so it passes under the southern part of the Kamchatka Peninsula. This is not a smooth process, the rocks of the two plates continuously stick together then, as the pressure builds up, break apart again, causing Earthquakes.
Earthquakes along subductive margins are particularly prone to causing tsunamis, since these often occur when the overlying plate has stuck to the underlying plate, being pulled out of shape by its movement.. Eventually the pressure builds up to far and the overlying plate snaps back, causing an Earthquake and a tsunami.
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