UPDATE – (10:45 a.m.) –  A destructive, Pacific-wide tsunami is not expected and there is no tsunami threat to Hawaiʻi, the Pacific Tsunami Warning center reported in an updated message issued at 10:41 a.m. HST.

From the USGS tectonic summary:

This September 18, 2025, M7.8 earthquake that occurred east of Petropavlovsk-Kamchatsky, Russia is an aftershock of the M8.8 Kamchatka Peninsula earthquake that struck on July 29, 2025. The aftershock resulted from shallow reverse faulting. As of its occurrence, the September 18, 2025, event is the largest aftershock recorded following the M8.8 mainshock, exceeding a nearby M7.4 aftershock that occurred on September 13. At the earthquake’s location, the Pacific Plate is moving west-northwest relative to the North American Plate at a rate of approximately 80 mm/year. The earthquake’s location and faulting mechanism are consistent with faulting along the subduction zone plate interface of the Kuril-Kamchatka arc.

Although earthquakes are often represented as points on maps, events of this magnitude are better described as slip across a broad fault area. Reverse faulting earthquakes of this size typically involve rupture dimensions of approximately 100 km in length and 50 km in width.

FIRST REPORT

(BIVN) – A powerful earthquake that struck off the east coast of Kamchatka, Russia on Thursday triggered a Tsunami Advisory for the Pacific.  

The earthquake, initially measured at a Magnitude 7.8, occurred at 8:58 a.m. HST on September 18. 

“A tsunami threat exists for parts of the Pacific located closer to the earthquake,” reported the Pacific Tsunami Warning Center. “But it is still too early to determine whether there is a possible tsunami threat to Hawaiʻi.” 

Emergency officials say that if there is a tsunami threat to Hawaiʻi, the earliest estimated time the hazard might begin is at 2:51 p.m. HST on Thursday afternoon. 

This is a breaking news story that will be updated when more information becomes available.