West Crater
Volcanic field in United States
Key Facts
Elevation
1,329 m (4,360 ft)
Type
Volcanic field
Location
45.880°, -122.080°
Region
High Cascades Volcanic Arc
Rock Type
Andesite / Basaltic Andesite
Tectonic Setting
Subduction zone
Location
Loading map...
Overview
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 to the SE of 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 8,000 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.
Volcanic Hazards & Risk Assessment
Primary Hazards
Risk Level
Geological Composition & Structure
Rock Types
Tectonic Setting
Age & Formation
Eruption Statistics & Analysis
| Metric | Value | Global Ranking | Significance |
|---|---|---|---|
| Total Recorded Eruptions | Unknown | Low | Moderately active volcano |
| Maximum VEI | VEI Unknown | Minor | Local impact potential |
| Recent Activity | 7776 years ago | Historical | Historically active |
Monitoring & Alert Status
Monitoring Networks
Current Status
Nearby Volcanoes in North America Volcanic Regions
Quick Info
- •Smithsonian ID: 321060
- •Evidence: Eruption Dated
- •Epoch: Holocene
About the Photo
West Crater is a 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 andesite lava dome with two small lava flows, one of which forms the bare area in the center. The 290-m-high dome formed about 8,000 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 scoria cones along a NW-SE zone.
Photo by Lee Siebert, 2002 (Smithsonian Institution).
Authority Sources
Related Volcanoes
Basic Information
This page shows basic data from the Smithsonian Global Volcanism Program. For more detailed information, visit the official Smithsonian page.