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Mount Bachelor

Find U.S. Volcano

At 2,764 meters (9,068 feet) high, Mount Bachelor is the prominent peak just south of the Three Sisters in central Oregon.

Quick Facts

Location: Oregon, Deschutes County

Latitude: 43.979° N

Longitude: 121.688° W

Elevation: 2,764 (m) 9,068 (f)

Volcano type: Stratovolcano

Composition: Basalt to Andesite

Most recent eruption: About 9,500 years ago

Threat Potential: Moderate*

*based on the National Volcano Early Warning System

Summary

It is located within the Deschutes National Forest, 20 km west-southwest of Bend, Oregon. Mount Bachelor is the largest volcano in the 25-km-long, north-south trending, Mount Bachelor volcanic chain, which is composed of numerous cinder cones, lava flows, and shield volcanoes and covers and area of nearly 250 km2 (100 mi2). Eruptions of the chain began during or closely following the retreat of late Pleistocene glaciers (after about 18 ka) and ended before the eruption of Mount Mazama (Crater Lake at 7.7 ka), with the main pulse of activity lasting perhaps only 3,000 years. The volcanic chain produced mainly lava flows and near-vent tephra falls. The chain is typical of one style of mafic (basalt to andesite) volcanism found throughout the Cascades Volcanic Arc—effusive eruptions from aligned short-lived volcanic vents.

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

Guidebook for field trip to the Mount Bachelor-South Sister-Bend area, central Oregon High Cascades

No abstract available.

Authors
William E. Scott, Cynthia A. Gardner, Scott A. Lundstrom, Brittain E. Hill, Edward M. Taylor, Andrei M. Sarna-Wojcicki, Charles E. Meyer, John K. Nakata, J.L. Slate, P.C. Russell

Science

Hazards Summary for Mount Bachelor

Although Mount Bachelor looks similar to many of the more long-lived and potentially dangerous volcanic peaks of the Cascade Range, the mountain is part of a mafic volcanic chain that poses little danger for future eruptive activity.
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Hazards Summary for Mount Bachelor

Although Mount Bachelor looks similar to many of the more long-lived and potentially dangerous volcanic peaks of the Cascade Range, the mountain is part of a mafic volcanic chain that poses little danger for future eruptive activity.
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Geology and History Summary for Mount Bachelor

Mount Bachelor is a basalt to basaltic andesite summit cone that sits atop a shield volcano 15 km southeast of South Sister.
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Geology and History Summary for Mount Bachelor

Mount Bachelor is a basalt to basaltic andesite summit cone that sits atop a shield volcano 15 km southeast of South Sister.
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Eruption History of Mount Bachelor Volcanic Chain

Four discrete eruptive episodes are recognized.
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Eruption History of Mount Bachelor Volcanic Chain

Four discrete eruptive episodes are recognized.
Learn More