Repetitive precision gravity studies at the Cerro Prieto and Heber geothermal fields

Technical Report · Wed Sep 01 04:00:00 EDT 1982

DOI:https://doi.org/10.2172/6608199· OSTI ID:6608199

Grannell, R B

To study subsidence and mass removal, a precise gravity network was established on 60 permanent monuments in the Cerro Prieto geothermal field in early 1978, and repeated annually through early 1981; the survey was tied to two bedrock sites outside the limits of the current production zone. The looping technique of station occupation was utilized, in which occupation of the base was followed by occupation of several stations, followed by a return to the base. Use of two LaCoste and Romberg gravity meters, and replication of values within loops as well as entire loops, enhanced precision such that the median standard deviations of the base-to-station differences, reduced to observed gravity values, ranged from 7 to 15 microgals for individual surveys. The smaller values were obtained as field and data reduction techniques were improved and experience was gained. A similar survey was initiated in the Heber area just north of the Mexican border in early 1980. It too was established on permanent monuments, was tied to bedrock stations outside the geothermal area, and used multiple repetitions of values with two meters to achieve high precision.

• Research Organization: California State Univ., Long Beach (USA). Dept. of Geological Scienes
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6608199
• Report Number(s): LBL-15073; ON: DE83004467
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150301* -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
ACCURACY
CALIBRATION
CERRO PRIETO GEOTHERMAL FIELD
DATA ANALYSIS
DATA PROCESSING
GEOPHYSICAL SURVEYS
GEOTHERMAL FIELDS
GRAVITY SURVEYS
Geothermal Legacy
HEBER GEOTHERMAL FIELD
MEASURING METHODS
MONITORING
PROCESSING
SURVEYS
TIDE