The mainshock was preceded by a magnitude 7.4 foreshock on July 20, 2025, which signaled heightened strain in the region.
Modeling indicates a rupture zone approximately 500–600 km long and 150–200 km wide . The energy release lasted roughly 3 to 4.5 minutes . 8.8The Last of Us
For further reading on the seismic history and technical modeling of this region, you can consult reports from the U.S. Geological Survey (USGS) and the ScienceDirect multidisciplinary analysis . The mainshock was preceded by a magnitude 7
The town of Severo-Kurilsk saw damage to every apartment building and the destruction of its port. Satellite imagery from Planet Labs also confirmed a broken floating pier at the Rybachy submarine base . For further reading on the seismic history and
Within 24 hours of the quake, Klyuchevskaya Sopka , Eurasia's highest active volcano, began erupting. On August 3, the Krasheninnikov volcano produced a 6-km eruption plume—its first known historical activity.