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Mount Rainier

Find U.S. Volcano

Mount Rainier, the highest peak in the Cascade Range at 4,392m (14,410 ft), forms a dramatic backdrop to the Puget Sound region.

Quick Facts

Location: Washington, Pierce County

Latitude: 46.853° N

Longitude: 121.76° W

Elevation: 4,392 (m) 14,410 (f)

Volcano type: Stratovolcano

Composition: Andesite to Dacite

Most recent eruption: about 1,000 years ago

Nearby towns: Orting, Seattle, Tacoma, Yakima

Threat Potential: Very High*

*based on the National Volcano Early Warning System

Summary

During an eruption 5,600 years ago the once-higher edifice of Mount Rainier collapsed to form a large crater open to the northeast much like that at Mount St. Helens after 1980. Ensuing eruptions rebuilt the summit, filling the large collapse crater. Large lahars (volcanic mudflows) from eruptions and from collapses of this massive, heavily glaciated andesitic volcano have reached as far as the Puget Sound lowlands. Since the last ice age, several dozen explosive eruptions spread tephra (ash, pumice) across parts of Washington. The last magmatic eruption was about 1,000 years ago. Extensive hydrothermal alteration of the upper portion of the volcano has contributed to its structural weakness promoting collapse. An active thermal system driven by magma deep under the volcano has melted out a labyrinth of steam caves beneath the summit icecap.

News

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Mount Rainier reminds us that September is National Preparedness Month

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USGS Offers Emergency Managers a New Tool to Assess Lahar Hazards at Mount Rainier

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Opportunity to Comment on Mount Rainier Lahar Detection and Seismic Monitoring System

Publications

2018 update to the U.S. Geological Survey national volcanic threat assessment

When erupting, all volcanoes pose a degree of risk to people and infrastructure, however, the risks are not equivalent from one volcano to another because of differences in eruptive style and geographic location. Assessing the relative threats posed by U.S. volcanoes identifies which volcanoes warrant the greatest risk-mitigation efforts by the U.S. Geological Survey and its partners. This update

Authors
John W. Ewert, Angela K. Diefenbach, David W. Ramsey

Science

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Mount Rainier Hosts Three Hydrothermal Monitoring Sites

Hydrothermal monitoring at Mount Rainier.
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Maintaining Monitoring Equipment on Mount Rainier

U.S. Geological Survey Cascades Volcano Observatory (CVO) regularly perform repairs, upgrades, and maintenance on the monitoring equipment on Mount Rainier.
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Maintaining Monitoring Equipment on Mount Rainier

U.S. Geological Survey Cascades Volcano Observatory (CVO) regularly perform repairs, upgrades, and maintenance on the monitoring equipment on Mount Rainier.
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Monitoring Lahars at Mount Rainier

The greatest potential volcanic hazard at Mount Rainier is a lahar, also known as a volcanic mudflow.
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Monitoring Lahars at Mount Rainier

The greatest potential volcanic hazard at Mount Rainier is a lahar, also known as a volcanic mudflow.
Learn More