Continuous Gravity Observations at The Geysers: A Preliminary Report
- Key words
- Monitoring; Gravity; USA; California; Geysers; Cryogenic Gravimeter; Mass Transport; Reservoir Production; Earthquakes; Rainfall; Instrumentation; Unocal; University of San Diego; USGS
- Location
- The Geysers, California
- Conference
- Geothermal Resources Council Transactions
- Year
- 1979
- Session
- Geophysical surveys; Gravity surveys
- Language
- English
Abstract
A cryogenic gravimeter has been installed at the Geysers to continuously monitor gravity variations at the ugal level. A 38 day record is presented to illustrate the type of information that can be obtained from such an instrument. In addition to information directly related to mass transport within the reservoir, the data reveal a sudden 5 ugal decrease in gravity prior to a local earthquake. We also observe a 5 ugal increase in gravity during a heavy rainfall; however, interpretation o gravity variations at this level is limited by uncertainty in tilting of the gravimeter pier. The potential impact of continuous gravity observations on the study of reservoir characteristics is discussed.
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