Earthquake monitoring at the Cerro Prieto geothermal field

Conference · Fri Feb 01 04:00:00 EST 1980

OSTI ID:5321796

Majer, E L; McEvilly, T V

A three-week study in spring 1978 revealed more moderate earthquake activity (one or two events/day, M/sub L/ greater than or equal to 1) in the Cerro Prieto production zone. Plotting these events on a Wadati diagram we estimated an 0.4 Poisson's ratio for the upper 1 to 2 km of the field. The events were centered near the western edge of the production zone, near well M-6, and indicated strikeslip movement on north-south faults. To monitor the earthquake activity and propagation characteristics within the production zone, a five-station, semi-permanent array was put into operation in September 1979. The stations are closely spaced (1 to 2 km), surrounding a central station at M-6. Each station consists of a three-component 4.5-Hz geophone in a 100-m well connected to a 12-bit triggered-digital-cassette recorder. Although each station operates independently, they are interconnected via a hard-wire link to a central site. The purpose of this link is twofold: first, to allow telemetry of any selected station to the central site for visual monitoring; second, to provide an automatic daily time calibration to keep inter-station errors to less than 5 ms. The data from these stations will be used to monitor earthquake activity and wave propagation characteristics associated with fluid withdrawal and/or injection in the geothermal reservoir.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.; California Univ., Berkeley (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5321796
• Report Number(s): LBL-9550; CONF-7910166-3
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150301* -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
150600 -- Geothermal Energy-- Environmental Aspects
CERRO PRIETO GEOTHERMAL FIELD
DATA ACQUISITION SYSTEMS
EARTHQUAKES
GEOTHERMAL FIELDS
Geothermal Legacy
MICROEARTHQUAKES
MONITORING
SEISMIC EVENTS
SEISMICITY