Database ID#: 176
Date: Tuesday, July 8, 2025
Location: Mount Rainier National Park
Glacier Name: None
Drainage Basin:
Event Type: Earthquake

Weather:
Warm

Season: Dry

Notes:
2025-07-11 09:00 update:
From the USGS/CVO:
CASCADES VOLCANO OBSERVATORY STATUS REPORT
U.S. Geological Survey
Friday, July 11, 2025, 9:12 AM PDT (Friday, July 11, 2025, 16:12 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 9 AM PDT (16:00 UTC) on July 11th, the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) have located 391 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 2.3 on July 8th at 2:56 PM PDT (21:56 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 Friday 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.


2025-07-09 09:30 update:
From USGS/CVO:
CASCADES VOLCANO OBSERVATORY STATUS REPORT
U.S. Geological Survey
Wednesday, July 9, 2025, 9:30 AM PDT (Wednesday, July 9, 2025, 16:30 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.
Seismicity is continuing at low rates. As of 9 AM PDT (16:00 UTC) on July 9th, the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) have located 229 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 2.1 on July 8th at 2:56 PM PDT (21:56 UTC). Seismicity has decreased from 26 located events per hour at the swarm's peak on Tuesday morning to a few per hour as of Wednesday morning. The average earthquake depth is 2.5 miles (4 km) beneath the summit. There have been no changes in ground deformation or other monitoring data.
The cause of the swarm remains consist with the circulation of fluids along preexisting faults beneath the volcano. 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.


2025-07-08 16:04 update:
Map/data of the swarm:
https://www.morageology.com/earthquake_range.php?d0=2025-07-08%2008:00:00&d1=2025-07-25%2023:59:59

Initial report, ongoing event:
From USGS/CVO:
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
On July 8, 2025, the U.S. Geological Survey Cascades Volcano Observatory (CVO) and Pacific Northwest Seismic Network (PNSN) detected a swarm of earthquakes at Mount Rainier starting at 01:29 PDT (08:29 UTC). So far, hundreds of earthquakes have been detected with event rates up to several per minute, ranging from depths of 1.2 – 3.7 miles (2-6 km) below the summit. The largest earthquake located thus far is a magnitude 1.7.
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.
Recent activity
Beginning at about 1:29 AM PDT (8:29 UTC) on July 8, a swarm of small earthquakes began near the summit of Mount Rainier. The Pacific Northwest Seismic Network is locating earthquakes with the largest so far being a M1.7 at 04:52 PDT (11:52 UTC), ranging from depths of 1.2 – 3.7 miles (2-6 km) below the summit. There are hundreds of small earthquakes occurring at rates of up to several per minute at times. No earthquakes have been felt at the surface.
Instruments do not show any detectable ground deformation at the volcano, and no anomalous signals have been seen on the infrasound monitoring stations. Mount Rainier does not have a dedicated continuous volcanic gas sampling capability.
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. 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. Past swarms have been attributed to circulation of fluids interacting with preexisting faults.


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