Three Sisters | U.S. Geological Survey
Source: https://www.usgs.gov/volcanoes/three-sisters
Archived: 2026-04-23 17:20
Three Sisters | U.S. Geological Survey
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Three Sisters
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The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows.
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The three aligned stratovolcanoes of North, Middle, and South Sister are closely spaced, but they display very little family resemblance.
Quick Facts
Location:
Oregon, Lane County
Latitude:
44.103° N
Longitude:
121.768° W
Elevation:
3,157 (m) 10,358 (f)
Volcano type:
Complex volcano
Composition:
Andesite to Rhyolite
Most recent eruption:
2,000 years ago
Threat Potential:
Very High*
*based on the
National Volcano Early Warning System
Summary
"For magnificence of glacial scenery, for wealth of recent lavas, and for graphic examples of dissected volcanoes, no part of this range surpasses the area embracing the Sisters and McKenzie Pass."
- Volcanologist Howel Williams, 1944
The three aligned stratovolcanoes of North, Middle, and South Sister are closely spaced, but they display very little family resemblance. North Sister is solely composed of basalt to andesite and is at least 120,000 years old. Middle Sister was built between 40 and 14 ka of magma ranging from basalt to dacite, with minor high-silica rhyolite. South Sister, composed of andesite to rhyolite, is the most silicic of all the cones and was constructed between 50 and 2 ka. The most recent eruptions were of rhyolite near South Sister, about 2,000 years ago. Scientific and public interest in the Three Sisters volcanic cluster was heightened in 2001 when scientists recognized that a phase of uplift had started in 1997 within a broad area about 6 km west of South Sister.
The Three Sisters lie within a broad area of densely spaced volcanic vents that, in the Cascades, is duplicated only in southern Washington and Northern California. The Sisters reach of the Cascade arc contains at least 466 volcanoes that erupted within the past one million years, and most are small single-eruption volcanic vents, though there are a few are low shields and stratocones such as Broken Top.
Scientists detect rejuvenated uplift near South Sister volcano.
January 31, 2022
Scientists detect rejuvenated uplift near South Sister volcano.
Which U.S. volcanoes pose a threat?
December 19, 2018
Which U.S. volcanoes pose a threat?
Geologic maps lay the foundation for this virtual tour of western states volcanoes.
January 8, 2018
Geologic maps lay the foundation for this virtual tour of western states volcanoes.
View All
October 22, 2018
2018 update to the U.S. Geological Survey national volcanic threat assessment
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...
Authors
John W. Ewert, Angela K. Diefenbach, David W. Ramsey
By
Volcano Hazards Program
,
Volcano Science Center
,
Agrigan
,
Ahyi Seamount
,
Alamagan
,
Anatahan
,
Asuncion
,
Belknap
,
Black Butte Crater Lava Field
,
Black Rock Desert Volcanic Field
,
Blue Lake Crater
,
Carrizozo Lava Flow
,
Cascade Range Weekly Update
,
Cinnamon Butte
,
Clear Lake Volcanic Field
,
Coso Volcanic Field
,
Crater Lake
,
Craters of the Moon Volcanic Field
,
Daikoku Seamount
,
Davis Lake Volcanic Field
,
Devils Garden Lava Field
,
Diamond Craters Volcanic Field
,
Dotsero Volcanic Center
,
East Diamante
,
Esmeralda Bank
,
Farallon de Pajaros
,
Fukujin Seamount
,
Glacier Peak
,
Guguan
,
Haleakalā
,
Hell's Half Acre Lava Field
,
Hualālai
,
Indian Heaven Volcanic Field
,
Jordan Craters Volcanic Field
,
Kama‘ehuakanaloa
,
Kasuga 2
,
Kīlauea
,
Lassen Volcanic Center
,
Long Valley Caldera
,
Mammoth Mountain
,
Markagunt Plateau Volcanic Field
,
Maug Islands
,
Mauna Kea
,
Mauna Loa
,
Medicine Lake
,
Mono Lake Volcanic Field
,
Mono-Inyo Craters
,
Mount Adams
,
Mount Bachelor
,
Mount Baker
,
Mount Hood
,
Mount Jefferson
,
Mount Rainier
,
Mount Shasta
,
Mount St. Helens
,
Newberry
,
Ofu-Olosega
,
Pagan
,
Red Hill-Quemado Volcanic Field
,
Ruby
,
Salton Buttes
,
San Francisco Volcanic Field
,
Sand Mountain Volcanic Field
,
Sarigan
,
Soda Lakes
,
South Sarigan Seamount
,
Supply Reef
,
Ta'u Island
,
Three Sisters
,
Tutuila Island
,
Ubehebe Craters
,
Uinkaret Volcanic Field
,
Valles Caldera
,
Wapi Lava Field
,
Weekly Update
,
West Crater Volcanic Field
,
Yellowstone
,
Zealandia Bank
,
Zuni-Bandera Volcanic Field
November 14, 2023
Hazards Summary for Three Sisters
Three Sisters is a potentially active volcanic center that lies close to rapidly growing communities and resort areas in Central Oregon.
By
Cascades Volcano Observatory
,
Three Sisters
Hazards Summary for Three Sisters
November 14, 2023
Hazards Summary for Three Sisters
Three Sisters is a potentially active volcanic center that lies close to rapidly growing communities and resort areas in Central Oregon.
Learn More
November 13, 2023
Lava Flow Hazards at Three Sisters
Volcanoes in the Three Sisters region have erupted a wide variety of magma types, therefore the shape, size, and impact of future lava flows could vary greatly.
By
Cascades Volcano Observatory
,
Three Sisters
Lava Flow Hazards at Three Sisters
November 13, 2023
Lava Flow Hazards at Three Sisters
Volcanoes in the Three Sisters region have erupted a wide variety of magma types, therefore the shape, size, and impact of future lava flows could vary greatly.
Learn More
November 12, 2023
Tephra Fall Hazards at Three Sisters
Eruptions from any volcano in the Three Sisters region, as well as from more distant volcanoes in the Cascade Range, are sources of potential tephra fall in Central Oregon communities.
By
Cascades Volcano Observatory
,
Three Sisters
Tephra Fall Hazards at Three Sisters
November 12, 2023
Tephra Fall Hazards at Three Sisters
Eruptions from any volcano in the Three Sisters region, as well as from more distant volcanoes in the Cascade Range, are sources of potential tephra fall in Central Oregon communities.
Learn More
View All
Quick Facts
Location:
Oregon, Lane County
Latitude:
44.103° N
Longitude:
121.768° W
Elevation:
3,157 (m) 10,358 (f)
Volcano type:
Complex volcano
Composition:
Andesite to Rhyolite
Most recent eruption:
2,000 years ago
Threat Potential:
Very High*
*based on the
National Volcano Early Warning System
Volcanoes Hazards Program Links
Assess
Prepare
Forecast
Activity
Products
Observatories
About
Was this page helpful?
Skip to main content
Official websites use .gov
A
.gov
website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A
lock (
)
or
https://
means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Three Sisters
Find U.S. Volcano
Filters
Learn More
The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows.
Get Help
Earthquake Plots
To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over.
Map Layers
Earthquake Colors
Earthquake Depth Units
Earthquake Time Units
Results
Filters
Learn More
The map displays volcanoes, earthquakes, monitoring instruments, and past lava flows.
Get Help
Earthquake Plots
To view an earthquake cross-sectional plot, click "Draw Plot" to start drawing on the map. Once the plot area is selected, click on "View Plot" to view chart or "Clear Plot" to start over.
Settings
Map Layers
Earthquake Colors
Earthquake Depth Units
Earthquake Time Units
x
Map Legend
x
Map Legend
Results
Three Sisters
Home
Science
Publications
Data
Maps
Multimedia
News
Connect
The three aligned stratovolcanoes of North, Middle, and South Sister are closely spaced, but they display very little family resemblance.
Quick Facts
Location:
Oregon, Lane County
Latitude:
44.103° N
Longitude:
121.768° W
Elevation:
3,157 (m) 10,358 (f)
Volcano type:
Complex volcano
Composition:
Andesite to Rhyolite
Most recent eruption:
2,000 years ago
Threat Potential:
Very High*
*based on the
National Volcano Early Warning System
Summary
"For magnificence of glacial scenery, for wealth of recent lavas, and for graphic examples of dissected volcanoes, no part of this range surpasses the area embracing the Sisters and McKenzie Pass."
- Volcanologist Howel Williams, 1944
The three aligned stratovolcanoes of North, Middle, and South Sister are closely spaced, but they display very little family resemblance. North Sister is solely composed of basalt to andesite and is at least 120,000 years old. Middle Sister was built between 40 and 14 ka of magma ranging from basalt to dacite, with minor high-silica rhyolite. South Sister, composed of andesite to rhyolite, is the most silicic of all the cones and was constructed between 50 and 2 ka. The most recent eruptions were of rhyolite near South Sister, about 2,000 years ago. Scientific and public interest in the Three Sisters volcanic cluster was heightened in 2001 when scientists recognized that a phase of uplift had started in 1997 within a broad area about 6 km west of South Sister.
The Three Sisters lie within a broad area of densely spaced volcanic vents that, in the Cascades, is duplicated only in southern Washington and Northern California. The Sisters reach of the Cascade arc contains at least 466 volcanoes that erupted within the past one million years, and most are small single-eruption volcanic vents, though there are a few are low shields and stratocones such as Broken Top.
Scientists detect rejuvenated uplift near South Sister volcano.
January 31, 2022
Scientists detect rejuvenated uplift near South Sister volcano.
Which U.S. volcanoes pose a threat?
December 19, 2018
Which U.S. volcanoes pose a threat?
Geologic maps lay the foundation for this virtual tour of western states volcanoes.
January 8, 2018
Geologic maps lay the foundation for this virtual tour of western states volcanoes.
View All
October 22, 2018
2018 update to the U.S. Geological Survey national volcanic threat assessment
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...
Authors
John W. Ewert, Angela K. Diefenbach, David W. Ramsey
By
Volcano Hazards Program
,
Volcano Science Center
,
Agrigan
,
Ahyi Seamount
,
Alamagan
,
Anatahan
,
Asuncion
,
Belknap
,
Black Butte Crater Lava Field
,
Black Rock Desert Volcanic Field
,
Blue Lake Crater
,
Carrizozo Lava Flow
,
Cascade Range Weekly Update
,
Cinnamon Butte
,
Clear Lake Volcanic Field
,
Coso Volcanic Field
,
Crater Lake
,
Craters of the Moon Volcanic Field
,
Daikoku Seamount
,
Davis Lake Volcanic Field
,
Devils Garden Lava Field
,
Diamond Craters Volcanic Field
,
Dotsero Volcanic Center
,
East Diamante
,
Esmeralda Bank
,
Farallon de Pajaros
,
Fukujin Seamount
,
Glacier Peak
,
Guguan
,
Haleakalā
,
Hell's Half Acre Lava Field
,
Hualālai
,
Indian Heaven Volcanic Field
,
Jordan Craters Volcanic Field
,
Kama‘ehuakanaloa
,
Kasuga 2
,
Kīlauea
,
Lassen Volcanic Center
,
Long Valley Caldera
,
Mammoth Mountain
,
Markagunt Plateau Volcanic Field
,
Maug Islands
,
Mauna Kea
,
Mauna Loa
,
Medicine Lake
,
Mono Lake Volcanic Field
,
Mono-Inyo Craters
,
Mount Adams
,
Mount Bachelor
,
Mount Baker
,
Mount Hood
,
Mount Jefferson
,
Mount Rainier
,
Mount Shasta
,
Mount St. Helens
,
Newberry
,
Ofu-Olosega
,
Pagan
,
Red Hill-Quemado Volcanic Field
,
Ruby
,
Salton Buttes
,
San Francisco Volcanic Field
,
Sand Mountain Volcanic Field
,
Sarigan
,
Soda Lakes
,
South Sarigan Seamount
,
Supply Reef
,
Ta'u Island
,
Three Sisters
,
Tutuila Island
,
Ubehebe Craters
,
Uinkaret Volcanic Field
,
Valles Caldera
,
Wapi Lava Field
,
Weekly Update
,
West Crater Volcanic Field
,
Yellowstone
,
Zealandia Bank
,
Zuni-Bandera Volcanic Field
November 14, 2023
Hazards Summary for Three Sisters
Three Sisters is a potentially active volcanic center that lies close to rapidly growing communities and resort areas in Central Oregon.
By
Cascades Volcano Observatory
,
Three Sisters
Hazards Summary for Three Sisters
November 14, 2023
Hazards Summary for Three Sisters
Three Sisters is a potentially active volcanic center that lies close to rapidly growing communities and resort areas in Central Oregon.
Learn More
November 13, 2023
Lava Flow Hazards at Three Sisters
Volcanoes in the Three Sisters region have erupted a wide variety of magma types, therefore the shape, size, and impact of future lava flows could vary greatly.
By
Cascades Volcano Observatory
,
Three Sisters
Lava Flow Hazards at Three Sisters
November 13, 2023
Lava Flow Hazards at Three Sisters
Volcanoes in the Three Sisters region have erupted a wide variety of magma types, therefore the shape, size, and impact of future lava flows could vary greatly.
Learn More
November 12, 2023
Tephra Fall Hazards at Three Sisters
Eruptions from any volcano in the Three Sisters region, as well as from more distant volcanoes in the Cascade Range, are sources of potential tephra fall in Central Oregon communities.
By
Cascades Volcano Observatory
,
Three Sisters
Tephra Fall Hazards at Three Sisters
November 12, 2023
Tephra Fall Hazards at Three Sisters
Eruptions from any volcano in the Three Sisters region, as well as from more distant volcanoes in the Cascade Range, are sources of potential tephra fall in Central Oregon communities.
Learn More
View All
Quick Facts
Location:
Oregon, Lane County
Latitude:
44.103° N
Longitude:
121.768° W
Elevation:
3,157 (m) 10,358 (f)
Volcano type:
Complex volcano
Composition:
Andesite to Rhyolite
Most recent eruption:
2,000 years ago
Threat Potential:
Very High*
*based on the
National Volcano Early Warning System
Volcanoes Hazards Program Links
Assess
Prepare
Forecast
Activity
Products
Observatories
About
Was this page helpful?