Seismometers at Mount Rainier recorded a 72-hour burst of underground vibrations starting November 15, 2025, around 5 a.m. ET, relevant to the Seattle–Tacoma area. The Mount Rainier tremor follows July 2025 earthquake swarms of 1,000+ small quakes, peaking at 41 per hour. USGS and PNSN link the shaking to the hydrothermal system; the alert remains GREEN NORMAL.<br /><br />About 300,000 residents lie in mapped hazard pathways, including more than 80,000 in lahar valleys. Orting and Puyallup face lahar travel times of roughly 30–45 minutes and 1–3 hours.<br /><br />During eruptions, glacier melt can drive lahars exceeding 60 mph. Twenty seismic stations monitor Rainier; no stronger tremor, deep earthquakes, or ground swelling are reported.
