Global Volcanism Program

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Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude

322090

5800 BCE

2,763 m / 9,065 ft

43.979°N
121.688°W

Morphology

Volcano Landform
Composite

Volcano Types
Stratovolcano
Shield(s)
Pyroclastic cone(s)

Rock Types

Major
Andesite / Basaltic Andesite
Basalt / Picro-Basalt

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km

18
24
22,514
231,420

Geological Summary

This volcanic system extends from Mount Bachelor on the N to Lookout Mountain about 20 km S, with a chain of scoria cones and small shield volcanoes between and additional volcanic features to the E. The basaltic andesite and basaltic volcanoes formed during four eruptive periods dating back to about 18,000-15,000 years before present (BP). Construction of the main scoria cone chain was completed by about 12,000 years BP, and Bachelor (formerly known as Bachelor Butte) is one of its youngest features. The latest activity produced lava flows on the E side of Sparks Lake from scoria cones on the NNE flank of Bachelor, and lava flows from Egan scoria cone on the N flank that slightly preceded the eruption of the Mazama ash from Crater Lake about 7,000-8,500 years ago.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Hildreth W E, 2007. Quaternary magmatism in the Cascades--geologic perpectives. U S Geol Surv Prof Pap, 1744: 1-125.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior.

Luedke R G, Smith R L, 1982. Map showing distribution, composition, and age of late Cenozoic volcanic centers in Oregon and Washington. U S Geol Surv Map, I-1091-D.

Peterson N V, Groh E A, 1966. Lunar Geological Field Conference guidebook. Oregon Dept Geol Min Ind, 51 p.

Peterson N V, Groh E A, Taylor E M, Stensland D E, 1976. Geology and mineral resources of Deschutes County Oregon. Oregon Dept Geol Min Ind Bull, 89: 1-62.

Scott W E, Gardner C A, 1992. Geologic map of the Mount Bachelor volcanic chain and surrounding area, Cascade Range, Oregon. U S Geol Surv Misc Invest Ser Map, I-1967, 1:50,000 geol map.

Scott W E, Gardner C A, 1990. Field trip guide to the central Oregon High Cascades, Part 1: Mount Bachelor-South Sister area. Oregon Geol, 52: 99-140.

Scott W E, Gardner C A, Sarna-Wojcicki A M, 1989. Guidebook for field trip to the Mount Bachelor-South Sister-Bend area, central Oregon High Cascades. U S Geol Surv Open-File Rpt, 89-645: 1-68.

Williams H, 1957. A geologic map of the Bend Quadrangle, Oregon and a reconnaissance geologic map of the central portion of the High Cascade Mountains. Oregon Dept Geol Min Ind, 1:125,000 and 1:250,000 scale.

Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

Eruptive History

There is data available for 1 confirmed Holocene eruptive periods.

5800 BCE ± 750 years Confirmed Eruption (Explosive / Effusive)

Episode 1 | Eruption (Explosive / Effusive)

North flank (Egan cone)

5800 BCE ± 750 years - Unknown

Evidence from Correlation: Magnetism

Eruptive activity low on the N flank of Mount Bachelor produced the Egan scoria cone and lava flows that dam Sparks Lake. The lavas are considered to be only slightly older than the ca. 6,850 years BP Mazama ash, and paleomagnetic evidence suggests an age between 7,000 and 8,500 years BP (Scott and Gardner, 1992).

List of 4 Events for Episode 1 at North flank (Egan cone)

Start Date	End Date	Event Type
- - - -	- - - -	Explosion
- - - -	- - - -	Lava flow
- - - -	- - - -	Cinder Cone
- - - -	- - - -	Tephra

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Synonyms

Bachelor Butte

Cones

Feature Name

Feature Type

Elevation

Latitude

Longitude

Dry Butte

Pyroclastic cone

43° 49' 0.00" N

121° 39' 0.00" W

Egan

Pyroclastic cone

2158 m

44° 0' 0.00" N

121° 41' 0.00" W

Klak Butte

Pyroclastic cone

43° 52' 0.00" N

121° 37' 0.00" W

Kwohl Butte

Shield volcano

2243 m

43° 58' 0.00" N

121° 41' 0.00" W

Lolah Butte

Pyroclastic cone

43° 50' 0.00" N

121° 41' 0.00" W

Lolo Butte

Pyroclastic cone

43° 51' 0.00" N

121° 37' 0.00" W

Lookout Mountain

Shield volcano

1894 m

43° 48' 0.00" N

121° 42' 0.00" W

Lumrun Butte

Pyroclastic cone

43° 50' 0.00" N

121° 41' 0.00" W

Pistol Butte

Pyroclastic cone

43° 49' 0.00" N

121° 33' 0.00" W

Red Crater

Pyroclastic cone

1646 m

43° 57' 0.00" N

121° 47' 0.00" W

Sheridan Mountain

Shield volcano

2100 m

43° 54' 0.00" N

121° 41' 0.00" W

Siah Butte

Pyroclastic cone

43° 51' 0.00" N

121° 41' 0.00" W

Sitkum Butte

Pyroclastic cone

43° 50' 0.00" N

121° 33' 0.00" W

Three Trappers

Pyroclastic cone

43° 50' 0.00" N

121° 41' 0.00" W

Tot Mountain

Pyroclastic cone

2329 m

43° 57' 0.00" N

121° 41' 0.00" W

Wake Butte

Pyroclastic cone

43° 50' 0.00" N

121° 37' 0.00" W

Photo Gallery

Mount Bachelor, SW of Bend, Oregon, is seen here from the north with a neoglacial moraine in the center. No known summit eruptions have occurred during the Holocene, although it was active until the latest Pleistocene and a N-flank vent produced a series of lava flows immediately preceding the eruption of the Mazama ash about 7,700 years ago.

Photo by Willie Scott, 1981 (U.S. Geological Survey).

Kwohl Butte scoria cone in the foreground is part of a 25-km-long chain of small shield volcanoes and scoria cones extending north to Mount Bachelor. South and Middle Sister volcanoes are visible to the left behind the eroded slopes of Bachelor.

Photo by Lee Siebert, 1981 (Smithsonian Institution).

Kwohl Butte is one in a 25-km-long chain of scoria cones and small shield volcanoes south of Mount Bachelor in the central Cascade Range of Oregon. Despite the youthful appearance of the cone, geologic mapping indicates construction of the chain was completed about 12,000 years ago.

Photo by Lee Siebert, 1981 (Smithsonian Institution).

Mount Bachelor, seen here from the summit of Broken Top volcano to the north, was constructed during the late Pleistocene. Holocene eruptions occurred at a cone on the north flank.

Photo by Lee Siebert, 1982 (Smithsonian Institution).

Mount Bachelor is seen here beyond Sparks Lake to the west. It is a late Pleistocene-to-Holocene stratovolcano at the northern end of a 25-km-long chain of scoria cones and small shield volcanoes.

Photo by Lee Siebert, 1982 (Smithsonian Institution).

Smithsonian Sample Collections Database

The following 3 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections, and may be availble for research (contact the Rock and Ore Collections Manager). Catalog number links will open a window with more information.

Catalog Number	Sample Description	Lava Source	Collection Date
NMNH 112584-1	Basalt	--	--
NMNH 112584-2	Basalt	--	--
NMNH 112584-3	Pumice	--	--

External Sites

Copernicus Browser

The Copernicus Browser replaced the Sentinel Hub Playground browser in 2023, to provide access to Earth observation archives from the Copernicus Data Space Ecosystem, the main distribution platform for data from the EU Copernicus missions.

MIROVA

Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.

MODVOLC Thermal Alerts

Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.

WOVOdat
   Single Volcano View
   Temporal Evolution of Unrest
   Side by Side Volcanoes

WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.

GVMID Data on Volcano Monitoring Infrastructure The Global Volcano Monitoring Infrastructure Database GVMID, is aimed at documenting and improving capabilities of volcano monitoring from the ground and space. GVMID should provide a snapshot and baseline view of the techniques and instrumentation that are in place at various volcanoes, which can be use by volcano observatories as reference to setup new monitoring system or improving networks at a specific volcano. These data will allow identification of what monitoring gaps exist, which can be then targeted by remote sensing infrastructure and future instrument deployments.

Volcanic Hazard Maps

The IAVCEI Commission on Volcanic Hazards and Risk has a Volcanic Hazard Maps database designed to serve as a resource for hazard mappers (or other interested parties) to explore how common issues in hazard map development have been addressed at different volcanoes, in different countries, for different hazards, and for different intended audiences. In addition to the comprehensive, searchable Volcanic Hazard Maps Database, this website contains information about diversity of volcanic hazard maps, illustrated using examples from the database. This site is for educational purposes related to volcanic hazard maps. Hazard maps found on this website should not be used for emergency purposes. For the most recent, official hazard map for a particular volcano, please seek out the proper institutional authorities on the matter.

IRIS seismic stations/networks

Incorporated Research Institutions for Seismology (IRIS) Data Services map showing the location of seismic stations from all available networks (permanent or temporary) within a radius of 0.18° (about 20 km at mid-latitudes) from the given location of Bachelor. Users can customize a variety of filters and options in the left panel. Note that if there are no stations are known the map will default to show the entire world with a "No data matched request" error notice.

UNAVCO GPS/GNSS stations

Geodetic Data Services map from UNAVCO showing the location of GPS/GNSS stations from all available networks (permanent or temporary) within a radius of 20 km from the given location of Bachelor. Users can customize the data search based on station or network names, location, and time window. Requires Adobe Flash Player.

DECADE Data

The DECADE portal, still in the developmental stage, serves as an example of the proposed interoperability between The Smithsonian Institution's Global Volcanism Program, the Mapping Gas Emissions (MaGa) Database, and the EarthChem Geochemical Portal. The Deep Earth Carbon Degassing (DECADE) initiative seeks to use new and established technologies to determine accurate global fluxes of volcanic CO₂ to the atmosphere, but installing CO₂ monitoring networks on 20 of the world's 150 most actively degassing volcanoes. The group uses related laboratory-based studies (direct gas sampling and analysis, melt inclusions) to provide new data for direct degassing of deep earth carbon to the atmosphere.

Large Eruptions of Bachelor

Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

EarthChem

EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).