Source: US Geological Survey
As of 1:00 PM PT on July 8, 2025 – an earthquake swarm, consisting of hundreds of very small earthquakes have occurred since approximately 1:30 AM PDT this morning. 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 1.6 at 04:52 AM PDT (11:52 UTC), ranging from depths of 1 to 4 miles (2-6 km) 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.
Typically, earthquakes at this volcano are located at a rate of about 9 earthquakes per month. Swarms typically occur 1-2 times per year, but are usually much smaller in terms of number of events. Earthquakes are one of several parameters we monitor to indicate what a volcano is doing. Right now, this swarm is still within what we consider normal background levels of activity at Mount Rainier. Past swarms have been attributed to circulation of fluids interacting with preexisting faults.
The last large swarm at Mount Rainier in 2009 had a maximum magnitude of M2.3 and lasted three days. The 2009 swarm had over 1000 earthquakes, of which the PNSN officially located 120 earthquakes.
To receive updates, you can sign up for USGS volcano notifications here: https://volcanoes.usgs.gov/vns/