An earthquake swarm that started at Mount Rainier on July 8, 2025, is the most significant seismicity at the volcano since 2009

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An earthquake swarm began at Mount Rainier, Washington, at 1:29 a.m. PDT (08:29 UTC) on July 8, 2025. An earthquake swarm is a cluster of earthquakes occurring in the same area in rapid succession. Currently, there is no indication that the level of earthquake activity is cause for concern, and the alert level and color code for Mount Rainier remain at GREEN / NORMAL.

The Pacific Northwest Seismic Network is in the process of looking at each earthquake and identifying its location, depth and size, if possible. This process is called locating. Some earthquakes are too small to locate. You can follow along in that process and watch the data on their website https://pnsn.org/volcanoes/mount-rainier.

This swarm consists of hundreds of very small earthquakes with the largest so far being a magnitude 2.3 at 9:03 a.m. PDT (16:03 UTC) on July 9, 2025. The Pacific Northwest Seismic Network has located 229 earthquakes as of 9 a.m. PDT on July 9; this number will increase as seismologists continue to analyze data. The earthquake rate has decreased over time, with a peak of 26 located events per hour on the morning of July 8 decaying to a few events per hour on the morning of July 9. The average earthquake depth is about 2.5 miles (4 kilometers) below the summit. Earthquakes are too small to be felt at the surface and will likely continue for several days. There would be no damage caused by such small events. MORE