Search Help
Did you find what you were looking for? Yes No
Ground Magnetic Data from within the Long Valley Caldera, California
Entry ID: USGS_OFR_2004_1096

[ Get Data ]

Summary
Abstract: The past two decades have been a period of unrest for the Long Valley caldera
of eastern California. The unrest began in 1978 and continued through late
1999 and included recurring swarms of moderate earthquakes, as well as
uplifting of the Resurgent Dome, which has totaled approximately 80 cm. It is
believed that the seismicity is accompanied by magmatic intrusion beneath both
the Resurgent Dome at a depth of about 7 km; 10 km and the South Moat Seismic
Zone (SMSZ) at a depth of about 15 km (Sorey and others, 2003). Seismic
surveys within the caldera's topographic boundary have indicated the seismicity
beneath the northwest section of the caldera is associated with fluid injection
into narrow conduits and fractures (Stroujkova and Malin, 2000). Like the
dominant regional structural trend, these conduits run in a northwest-southeast
direction and are only expressed at the surface by a slight topographic relief
of about 3 m. Merged aeromagnetic data (Roberts and Jachens, 1999) over the
caldera show a magnetic low in the west and a high in the east (Figure 3). The
western part has been modeled to relate to altered, low-magnetization (about
2.5 km thick) Bishop Tuff beneath the Resurgent Dome, indicating hydrothermal
alteration in the west, whereas the high in the east represents the unaltered
Bishop Tuff (Williams and others, 1977). The ground magnetic survey was
conducted to locate magnetic lows that might indicate altered zones reflecting
conduits for hydrothermal fluid flow in the northwest portion of the caldera.

[Summary provided by the USGS.]

Related URL
Link: GET DATA
Description: Download Long Valley ground magnetic data.


Geographic Coverage
 N: 42.51 S: 32.02  E: -113.61  W: -124.9

Data Set Citation
Dataset Originator/Creator: E. D. Anderson and C. A. Finn
Dataset Title: Ground Magnetic Data from within the Long Valley Caldera, California
Dataset Series Name: Open File Report 2004
Dataset Release Date: 2004
Dataset Publisher: U.S. Geological Survey
Data Presentation Form: online files
Online Resource: http://pubs.usgs.gov/of/2004/1096/


Temporal Coverage
Start Date: 2003-07-27
Stop Date: 2003-08-01


Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA > CALIFORNIA


Science Keywords
SOLID EARTH >GEOMAGNETISM >MAGNETIC FIELD >MAGNETIC ANOMALIES    [Definition]
SOLID EARTH >GEOMAGNETISM >MAGNETIC FIELD    [Definition]
SOLID EARTH >GEOMAGNETISM >MAGNETIC FIELD >MAGNETIC INTENSITY    [Definition]
SOLID EARTH >TECTONICS >EARTHQUAKES >EARTHQUAKE MAGNITUDE/INTENSITY    [Definition]
SOLID EARTH >TECTONICS >EARTHQUAKES >EARTHQUAKE OCCURRENCES    [Definition]
SOLID EARTH >TECTONICS >EARTHQUAKES >EARTHQUAKE PREDICTIONS    [Definition]
SOLID EARTH >TECTONICS >PLATE TECTONICS    [Definition]


ISO Topic Category
GEOSCIENTIFIC INFORMATION


Platform
FIELD SURVEYS    [Information]
MAPS    [Information]


Instrument
MAGNETOMETERS    [Information]
GPS >Global Positioning System    [Information]


Keywords
OFR
Open File Report
Caldera
Ground Magnetics
Seismic Surveys
Tectonics


Data Set Progress
IN WORK


Originating Center
USGS


Data Center
Publications-Western Region,Geological Division, U.S. Geological Survey, U.S. Department of the Interior    [Information]
Data Center URL: http://geopubs.wr.usgs.gov/

Data Center Personnel
Name: CAROLYN A. DONLIN
Phone: 650-329-5015
Fax: 650-329-5119
Email: cdonlin at usgs.gov
Contact Address:
U.S. Geological Survey
Geology Division
345 Middlefield Road
City: Menlo Park
Province or State: California
Postal Code: 94025
Country: USA



Distribution
Distribution_Media: online
Distribution_Format: ASCII
Fees: No fees


Personnel
CAROL A FINN
Role: TECHNICAL CONTACT
Phone: 303-236-1345
Fax: 303-236-1229
Email: cfinn at usgs.gov
Contact Address:
U.S. Geological Survey
MS 964
Denver Federal Center
City: Denver
Province or State: CO
Postal Code: 80225
Country: USA


ERIC D. ANDERSON
Role: TECHNICAL CONTACT
Phone: 303-236-5652
Email: ericanderson at usgs.gov
Contact Address:
U.S. Geological Survey, Geology Division
Box 25046, MS 964
Denver Federal Center
City: Denver
Province or State: CO
Postal Code: 80225-0046
Country: USA


Publications/References
Roberts, C. W. and Jachens, R. C., 1999, Preliminary aeromagnetic anomaly map of California: U.S. Geological Survey Open-File Report 99-440, scale 1:250,000. Sorey, M. L., McConnell, V. S., and Roeloffs, E., 2003, Summary of recent research in Long Valley Caldera, California: Journal of Volcanology and Geothermal Research, v. 127 pp. 165-173.

Stroujkova, A. F and Malin, P. E., 2000, A magma mass beneath Casa Diable?
Further evidence from reflected seismic waves: Bulletin of the Seismological
Society of America, v. 90, no. 2 pp. 500-511.

Willams, D. L., Berkman, F., and Mankinen, E. A., 1977, Implications of a
magnetic model of the Long Valley Caldera, California: Journal of Geophysical Research, v. 82, no. 20, pp. 3030-3038.

Creation and Review Dates
DIF Creation Date: 2006-01-17
Last DIF Revision Date: 2016-01-27



Link to Web Site