West Crater

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  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 45.88°N
  • 122.08°W

  • 1329 m
    4359 ft

  • 321060
  • Latitude
  • Longitude

  • Summit

  • Volcano

The Global Volcanism Program has no activity reports for West Crater.

The Global Volcanism Program has no Weekly Reports available for West Crater.

The Global Volcanism Program has no Bulletin Reports available for West Crater.

Basic Data

Volcano Number

Last Known Eruption



5750 BCE

1329 m / 4359 ft


Volcano Types

Volcanic field

Rock Types

Andesite / Basaltic Andesite
Basalt / Picro-Basalt

Tectonic Setting

Subduction zone
Continental crust (> 25 km)


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

Geological Summary

West Crater, a small andesitic lava dome with associated lava flows, is part of a Quaternary volcanic field in southern Washington consisting primarily of small basaltic and basaltic andesite cinder cones and shield volcanoes, oriented along a NW-SE zone SE of Mount St. Helens. This 20-km-wide zone extends from Marble Mountain, north of Swift Reservoir, to south of Trout Creek Hill. The Pleistocene basaltic Trout Creek Hill shield volcano produced a lava flow about 340,000 years ago that traveled 20 km SE, temporarily damming the Columbia River. At least three vents in this field are of Holocene age--West Crater, a small cone at Hackamore Creek, and a phreatic crater at the summit of Bare Mountain. The latest eruptions at these locations have been dated at about 8000 years before present, and have included emplacement of an andesitic lava dome and associated lava flow at West Crater and formation of a phreatic explosion crater at Bare Mountain.


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

Barnett B, Korosec M A, 1986. Geothermal exploratory drilling by the State of Washington in 1985. Wash Geol Newsl, 14: 21-28.

Hammond P E, Pedersen S A, Hopkins K D, Aiken D, Harle D S, Danes Z F, Konicek D L, Stricklin C R, 1976. Geology and gravimetry of the Quaternary basaltic volcanic field, southern Cascade Range, Washington. In: {Proc 2nd United Nations Symp Devel Use Geotherm Resour, San Francisco}, Washington D C: U S Government Printing Office, 1: 397-405.

Wise W S, 1970. Cenozoic volcanism in the Cascade Mountains of southern Washington. Wash Dept Nat Resour Bull, 60: 1-45.

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

Eruptive History

Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
5750 BCE (?) Unknown Confirmed 2 Radiocarbon (uncorrected) Bare Mountain
6110 BCE (?) Unknown Confirmed 2 Radiocarbon (uncorrected) West Crater, Hackamore Creek cone

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.


Feature Name Feature Type Elevation Latitude Longitude
Bare Mountain Cone 1329 m
Hackamore Creek Cone
Soda Peak Pyroclastic cone 45° 55' 0" N 122° 5' 0" W
Timbered Peak Cone 45° 59' 0" N 122° 8' 0" W
Trout Creek Hill Shield volcano 893 m 45° 50' 0" N 122° 0' 0" W

Photo Gallery

The valley floor in the foreground of this area of extensive logging clearcuts SE of Mount St. Helens, the peak seen in the distance, is covered by lava flows from West Crater and the Hackamore Creek scoria cone just NW of West Crater. Carbon fragments from a black tephra deposit produced by the Hackamore Creek scoria cone were dated at about 8000 years.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The forest-covered Bare Mountain explosion crater in the foreground is 400-m-wide and 275-m-deep. It formed about 7700 years ago during the youngest volcanic eruption in the West Crater volcanic field. West Crater itself is visible 4 km to the south at the extreme right side of the photo. The Bare Mountain phreatic crater was formed in older Tertiary volcanic rocks, and unlike other Holocene eruptions in the West Crater area, was not accompanied by lava flows.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
Trout Creek Hill, a small Quaternary shield volcano in the West Crater volcanic field, is seen here from the NW, with Mount Hood across the Columbia River in Oregon in the background. Lava flows from Trout Creek Hill traveled 13 km to the SE, reaching the Columbia River.

Photo by Lee Siebert, 1995 (Smithsonian Institution).
The large partially forested lava flow in the foreground originated from West Crater, out of view to the right, about 8000 years ago. The blocky andesitic flow, seen here about 2 km from the vent, traveled about 4.5 km to the SE. In addition to this eastern flow, another lava flow traveled to the NW down the Hackamore Creek drainage. West Crater is a lava dome with a 200-m-wide summit crater that straddles a topographic divide in southern Gifford Pinchot National Forest.

Photo by Lee Siebert, 2002 (Smithsonian Institution).
West Crater is a little-known Quaternary volcanic field in the southern Cascades of Washington between Mount St. Helens and Mount Hood. West Crater itself, seen here from the NE, is an andesitic dome with two small lava flows, one of which forms the bare area at the right center. The 290-m-high dome was formed about 8060 years ago on the floor of a cirque carved into older Tertiary volcanic rocks. The West Crater volcanic field consists of a series of small shield volcanoes and cinder cones along a NW-SE zone.

Photo by Lee Siebert, 2002 (Smithsonian Institution).

Smithsonian Sample Collections Database

The following 2 samples associated with this volcano can be found in the Smithsonian's NMNH Department of Mineral Sciences collections. Catalog number links will open a window with more information.

Catalog Number Sample Description
NMNH 117652-38 Basalt
NMNH 117652-39 Basalt

Affiliated Sites

Large Eruptions of West Crater 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).
WOVOdat 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.
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).
MODVOLC - HIGP MODIS Thermal Alert System 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.
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.