USGS Volcano Notice - DOI-USGS-CVO-2025-07-12T14:11:01+00:00

CASCADES VOLCANO OBSERVATORY STATUS REPORT
U.S. Geological Survey
Saturday, July 12, 2025, 8:06 AM PDT (Saturday, July 12, 2025, 15:06 UTC)

MOUNT RAINIER (VNUM #321030)
46°51'11" N 121°45'36" W, Summit Elevation 14409 ft (4392 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

This is an update on the ongoing seismic swarm at Mount Rainier that began at 1:29 AM PDT (8:29 UTC) on July 8th. 

Swarm event rates continue to decrease. As of 8 AM PDT (15:00 UTC) on July 12th, the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) have located 464 events since the start of the swarm, although many more have occurred but cannot be located. The largest event of the swarm so far was a magnitude 2.4 that occurred on July 11th at 12:23 PM PDT (19:23 UTC). Seismicity has decreased from 30 located events per hour at the swarm's peak on Tuesday morning to a few events per hour as of Saturday morning. The earthquakes are mainly spread between 1.5-4 miles (2-6 km) beneath the summit. There have been no changes in ground deformation or other monitoring data. 

This swarm surpassed the 2009 swarm in terms of total events, event rate, and energy release. The cause of the swarm remains consistent with the circulation of fluids along preexisting faults beneath the volcano, which is considered background activity at Mount Rainier. There is currently no indication that the swarm is associated with magmatic unrest. 

PNSN and CVO will continue to monitor activity, locate earthquakes, and provide additional information as needed.

For more information, see: https://www.usgs.gov/observatories/cvo/news/monitoring-stations-detect-small-magnitude-earthquakes-mount-rainier

About Mount Rainier

Mount Rainier is an active, ice-clad stratovolcano geographically located within the Mount Rainier National Park. Mount Rainier is located about 45 miles (73 km) southeast of Tacoma and 60 miles (97 km) south-southeast of Seattle in Washington State. It is the tallest peak in the Cascade Range and is covered by the greatest concentration of glaciers in the contiguous United States.

Hazards and Normal Background Activity

The most hazardous phenomena from Mount Rainier are volcanic mudflows called lahars, many of which reached as far as the now densely inhabited Puget Sound lowland. Other hazards include ash fall, pyroclastic flows, and short lava flows, however these stay well within the present limits of the National Park. Mount Rainier is considered a Very High Threat volcano according to the USGS National Volcano Warning System (NVEWS) based on many factors including the types of hazards and distance to people, property and infrastructure. The volcano has a widely distributed network of monitoring devices. Normal background levels of activity at Mount Rainier include steam and gas emissions, and low levels of seismicity.

Holocene Volcanic Activity (activity in the last 15,000 years)

Nearly all of Mount Rainier’s far-traveled lahars formed during times of eruptions, but one contains a large volume of altered rock that avalanched from Sunset Amphitheater on Mount Rainier’s upper west flank about 500 years ago with no known triggering eruption. A lahar with no known trigger is known locally as a “no-notice lahar.” Future eruptions are likely to produce lahars that could descend river valleys on any side of the volcano, but a “no-notice lahar” is also possible from the upper west flank of the volcano and could feed into the Puyallup and the Nisqually River systems. No physical evidence exists to confirm a reported but disputed eruption in 1894, nor eruptions earlier in the 18th and 19th centuries.  The most recent eruption with strong geologic evidence was about 1,000 years ago.

The U.S. Geological Survey Cascades Volcano Observatory and the University of Washington Pacific Northwest Seismic Network continue to monitor Washington and Oregon volcanoes closely and will issue additional notifications as warranted.

Website Resources

For images, graphics, and general information on Cascade Range volcanoes: https://www.usgs.gov/observatories/cvo
For seismic information on Oregon and Washington volcanoes: http://www.pnsn.org/volcanoes
For information on USGS volcano alert levels and notifications: https://www.usgs.gov/programs/VHP/volcano-notifications-deliver-situational-information

CONTACT INFORMATION:

Michael Poland, Acting Scientist-in-Charge, Cascades Volcano Observatory, mpoland@usgs.gov

General inquiries: askCVO@usgs.gov

Media inquiries: volcanomedia@usgs.gov