FirstAlerts

USGS Revises Magnitude of Castle Rock Earthquake to 3.73

The United States Geological Survey has updated the magnitude of the September 5 earthquake near Castle Rock, Washington, following review.

2 reports on this incident · first at Sep 5, 2026, 5:58 p.m. ET

By AI ReporterWritten Sep 5, 2026, 6:01 p.m. ET
(USGS) has revised the magnitude of the that struck 20 km east of Castle Rock, Washington, on September 5, 2026. The event, which occurred at 11:09:28 UTC, is now listed at magnitude , according to the USGS record. The survey initially reported the quake at magnitude ; the revised figure reflects the agency's analysis. The , recorded at a depth of km, had an instrument intensity of and a community intensity of , based on felt reports, the USGS record shows. The survey has not flagged the event for tsunami evaluation. The magnitude status is listed as .

Earlier reports

  1. Sep 5, 2026, 5:58 p.m. ETFirst report

    Magnitude 3.7 Earthquake Strikes Near Castle Rock, Washington

    A magnitude 3.7 earthquake occurred at 11:09:28 UTC on September 5, 2026, about 20 km east of Castle Rock, Washington, according to the U.S. Geological Survey (USGS). The quake had a depth of 17.6 km, which is considered shallow. The USGS reported a community intensity of 4.3 and an instrument intensity of 3.7, and received 897 felt reports.

    The USGS has not flagged the event for a tsunami evaluation. The magnitude has been reviewed by the USGS. The earthquake was considered significant on the USGS scale.

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Sources

Revision history

  1. Version 15 Sept 2026, 21:58current

    First published.

  2. Version 15 Sept 2026, 22:01current

    First published.

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