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Mammoth Mountain

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Mammoth Mountain is a 3,369-m (11,053 ft) high lava-dome complex on the southwest topographic rim of Long Valley Caldera. It is considered to represent a magmatic system distinct from Long Valley Caldera and the Mono-Inyo Craters.

Quick Facts

Location: California, Mono County

Latitude: 37.631° N

Longitude: 119.032° W

Elevation: 3,369 (m) 11,053 (f)

Volcano type: lava domes

Composition: trachydacite

Most recent eruption: 700 years ago (phreatic)

Nearby towns: Mammoth Lakes

Threat Potential: Moderate*

*based on the National Volcano Early Warning System

Summary

A deep blue lake is nestled in pine forest at the foot of a rocky, hilly peak
View of the Mammoth Mountain lava dome complex overlooking Horseshoe Lake.

Eruptions at Mammoth Mountain occurred from 100,000 to 50,000 years ago. Mammoth Mountain is surrounded by at least 35 mafic vents that are part of the same magmatic system and include Red Cones, two closely spaced basaltic cinder cones located southwest of Mammoth Mountain and southeast of Devils Postpile National Monument. The cones, whose name derives from colorful mantling scoria deposits, are unglaciated and were radiocarbon dated at about 8,000 years ago. Phreatic eruptions, distinct from those at South Inyo Craters, took place about 700 years ago from vents on the north side of Mammoth Mountain. Recent volcanic unrest, including seismicity, gas emission, and tree kill, is thought to be related to a dike intrusion beneath Mammoth Mountain in 1989. Both Long Valley Caldera and Mammoth Mountain have experienced episodes of heightened unrest over the last few decades (earthquakes, ground uplift, and/or volcanic gas emissions). As a result, the USGS manages a dense array of field sensors providing the real-time data needed to track unrest and assess hazards.

News

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Unpacking CalVO's new seismic monitoring boxes

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Geologic maps lay the foundation for this virtual tour of western states volcanoes.

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What's Under Long Valley? Water, Heat, and Molten Rock!

Publications

California’s exposure to volcanic hazards

The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years, and future volcanic eruptions are inevitable.The

Authors
Margaret Mangan, Jessica Ball, Nathan Wood, Jamie L. Jones, Jeff Peters, Nina Abdollahian, Laura Dinitz, Sharon Blankenheim, Johanna Fenton, Cynthia Pridmore

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

The California Volcano Observatory: Monitoring the state's restless volcanoes

Volcanic eruptions happen in the State of California about as frequently as the largest earthquakes on the San Andreas Fault Zone. At least 10 eruptions have taken place in California in the past 1,000 years—most recently at Lassen Peak in Lassen Volcanic National Park (1914 to 1917) in the northern part of the State—and future volcanic eruptions are inevitable. The U.S. Geological Survey Californ

Authors
Wendy K. Stovall, Mae Marcaida, Margaret T. Mangan

Science

Volcanic Gas Monitoring at Mammoth Mountain

USGS Volcano Hazards Program researchers evaluate changes in volcanic gas concentration at Mammoth Mountain.
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Volcanic Gas Monitoring at Mammoth Mountain

USGS Volcano Hazards Program researchers evaluate changes in volcanic gas concentration at Mammoth Mountain.
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Deformation monitoring at Mammoth Mountain

When magma moves into a volcanic system, and closer to the surface of the earth, the area surrounding the volcano may move upward and outward. This swelling is typically measured using the Global Positioning System (GPS). The GPS receivers near Mammoth Mountain are part of the 46 instruments that make up the Long Valley Caldera deformation monitoring network.
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Deformation monitoring at Mammoth Mountain

When magma moves into a volcanic system, and closer to the surface of the earth, the area surrounding the volcano may move upward and outward. This swelling is typically measured using the Global Positioning System (GPS). The GPS receivers near Mammoth Mountain are part of the 46 instruments that make up the Long Valley Caldera deformation monitoring network.
Learn More

Seismic monitoring at Mammoth Mountain

The seismometers located near Mammoth Mountain are part of the greater Long Valley Caldera seismic network array. Data from group of 61 seismometers help to determine earthquake location, energy, waveform and evolution of movement with time.
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Seismic monitoring at Mammoth Mountain

The seismometers located near Mammoth Mountain are part of the greater Long Valley Caldera seismic network array. Data from group of 61 seismometers help to determine earthquake location, energy, waveform and evolution of movement with time.
Learn More