Coso Volcanic Field

Photo of this volcano
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 36.03°N
  • 117.82°W

  • 2400 m
    7872 ft

  • 323180
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

Most Recent Bulletin Report: February 1992 (BGVN 17:02) Citation IconCite this Report


Tectonic earthquake swarm

A seismic swarm started on 17 February, with activity peaking by 20 February, and still declining as of 26 February (figure 1). More than 300 small high-frequency earthquakes (eight with M > 3.0) were recorded, the largest (M 4.0) at 0319 on 19 February. Hypocenters show a 3-km-long pattern elongated to the NNW, at 3-5 km depths (figure 2). The focal mechanism for the largest event showed mainly strike-slip motion (right-lateral on a N-S plane, or left-lateral on an E-W plane), with a small normal component. There were no reports of injuries or damages.

Figure (see Caption) Figure 1. Hourly number of earthquakes in the Coso Mountains, 17-26 February 1992. Courtesy of the USGS.
Figure (see Caption) Figure 2. Epicenter map (top) and E-W cross-section showing focal depths (bottom) of >300 high-frequency earthquakes recorded in the Coso Mountains, 17-26 February 1992. Courtesy of the USGS.

The Coso region is an active geothermal area that has had seismic swarms in the past, as in 1982 when thousands of events were recorded, the largest M 4.9. The Volcano Peak cinder cone and lava flow, apparently the youngest features in the Coso Mountains, are believed to have been erupted 0.039 ± 0.033 mybp. (K/Ar age).

Information Contacts: J. Mori and W. Duffield, USGS.

The Global Volcanism Program has no Weekly Reports available for Coso Volcanic Field.

Bulletin Reports - Index


Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

02/1992 (BGVN 17:02) Tectonic earthquake swarm




Information is preliminary and subject to change. All times are local (unless otherwise noted)


February 1992 (BGVN 17:02) Citation IconCite this Report


Tectonic earthquake swarm

A seismic swarm started on 17 February, with activity peaking by 20 February, and still declining as of 26 February (figure 1). More than 300 small high-frequency earthquakes (eight with M > 3.0) were recorded, the largest (M 4.0) at 0319 on 19 February. Hypocenters show a 3-km-long pattern elongated to the NNW, at 3-5 km depths (figure 2). The focal mechanism for the largest event showed mainly strike-slip motion (right-lateral on a N-S plane, or left-lateral on an E-W plane), with a small normal component. There were no reports of injuries or damages.

Figure (see Caption) Figure 1. Hourly number of earthquakes in the Coso Mountains, 17-26 February 1992. Courtesy of the USGS.
Figure (see Caption) Figure 2. Epicenter map (top) and E-W cross-section showing focal depths (bottom) of >300 high-frequency earthquakes recorded in the Coso Mountains, 17-26 February 1992. Courtesy of the USGS.

The Coso region is an active geothermal area that has had seismic swarms in the past, as in 1982 when thousands of events were recorded, the largest M 4.9. The Volcano Peak cinder cone and lava flow, apparently the youngest features in the Coso Mountains, are believed to have been erupted 0.039 ± 0.033 mybp. (K/Ar age).

Information Contacts: J. Mori and W. Duffield, USGS.

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.

Eruptive History


The Global Volcanism Program is not aware of any Holocene eruptions from Coso Volcanic Field. If this volcano has had large eruptions (VEI >= 4) prior to 10,000 years ago, information might be found on the Coso Volcanic Field page in the LaMEVE (Large Magnitude Explosive Volcanic Eruptions) database, a part of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).

Deformation History


There is data available for 1 deformation periods. Expand each entry for additional details.


Deformation during 1992 - 1997 [Subsidence; Observed by InSAR]

Start Date: 1992 Stop Date: 1997 Direction: Subsidence Method: InSAR
Magnitude: Unknown Spatial Extent: 15.00 km Latitude: 36.000 Longitude: -118.000

Remarks: Subsidence of the Coso geothermal area has a short-wavelength component that is likely anthropogenic in nature, and a long-wavelength component that is probably magmatic.

Five unwrapped interferograms in order of increasing amount of time spanned (Table1). The colorbar shows the correspondence between range change and color. Black areas correspond to regions of low coherence. (a) An 32-month interferogram fromSeptember 15, 1993, to May 10, 1996, (b) an 34-month interferogram from June 17, 1992, to April 21, 1995, (c) an 44-month interferogram from September 30, 1992, to May 11, 1996, (d) an 51-month interferogram from June 17, 1992, to September 28, 1996, and (e) an 61-month interferogram from June 17, 1992, to July 5, 1997.

From: Wicks et al. 2001.


Reference List: Fialko and Simons 2000; Wicks et al. 2001.

Full References:

Fialko, Y., & Simons, M., 2000. Deformation and seismicity in the Coso geothermal area, Inyo County, California: Observations and modeling using satellite radar interferometry. Journal of Geophysical Research B, 105(B9), 21781-21793.

Wicks, C. W., Jr., W. Thatcher, F. C. Monastero, and M. A. Hasting,, 2001. Steady state deformation of the Coso Range, east central California, inferred from satellite radar interferometry. J. Geophys. Res., 106, p. 13,769-13,780..

Emission History


There is no Emissions History data available for Coso Volcanic Field.

The Global Volcanism Program has no photographs available for Coso Volcanic Field.

Smithsonian Sample Collections Database


The following 51 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 117460-100 Rhyolite -- --
NMNH 117460-101 Rhyolite -- --
NMNH 117460-102 Rhyolite Dome #22 --
NMNH 117460-103 Rhyolite -- --
NMNH 117460-104 Obsidian -- --
NMNH 117460-105 Perlite -- --
NMNH 117460-106 Obsidian Dome #24 --
NMNH 117460-107 Obsidian Dome #26 --
NMNH 117460-108 Obsidian Dome #27 --
NMNH 117460-109 Rhyolite Dome #28 --
NMNH 117460-110 Rhyolite Dome #29 --
NMNH 117460-111 Rhyolite Dome #30 --
NMNH 117460-112 Rhyolite Dome #31 --
NMNH 117460-113 Rhyolite Dome #32 --
NMNH 117460-114 Rhyolite Dome #33 --
NMNH 117460-115 Rhyolite Dome #34 --
NMNH 117460-116 Rhyolite Dome #35 --
NMNH 117460-117 Rhyolite Dome #36 --
NMNH 117460-159 Rhyolite Dome #1 --
NMNH 117460-160 Rhyolite Dome #9 --
NMNH 117460-161 Rhyolite Dome #11 --
NMNH 117460-162 Rhyolite Dome #12 --
NMNH 117460-163 Obsidian Dome #16 --
NMNH 117460-164 Obsidian Dome #17 --
NMNH 117460-165 Rhyolite Dome #23 --
NMNH 117460-166 Obsidian Dome #25 --
NMNH 117460-167 Obsidian Dome #38 --
NMNH 117460-168 Rhyolite Dome #29 --
NMNH 117460-169 Pumice Dome #29 --
NMNH 117460-172 Rhyolite Dome #2 --
NMNH 117460-173 Rhyolite Dome #37 --
NMNH 117460-74 Marekanite Olancha dome --
NMNH 117460-81 Rhyolite -- --
NMNH 117460-82 Rhyolite Dome #2 --
NMNH 117460-83 Rhyolite Dome #3 --
NMNH 117460-84 Rhyolite -- --
NMNH 117460-85 Perlite Dome #4 --
NMNH 117460-86 Obsidian Dome #5 --
NMNH 117460-87 Obsidian Dome #6 --
NMNH 117460-88 Rhyolite Dome #7 --
NMNH 117460-89 Rhyolite Dome #8 --
NMNH 117460-90 Obsidian Dome #10 --
NMNH 117460-91 Obsidian Dome #13 --
NMNH 117460-92 Obsidian Dome #14 --
NMNH 117460-93 Obsidian Dome #15 --
NMNH 117460-94 Obsidian Dome #18 --
NMNH 117460-95 Obsidian Dome #19 --
NMNH 117460-96 Obsidian Dome #20 --
NMNH 117460-97 Obsidian Dome #20 --
NMNH 117460-98 Obsidian Dome #20 --
NMNH 117460-99 Rhyolite Dome #21 --

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