Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Resistivity studies on the Imperial Valley geothermal area, California

Journal Article · · Geothermics, v. 1, no. 2, pp. 47-62
Electrical resistivity was employed for mapping the Imperial Valley of California as part of a multi-disciplinary approach to assess its geothermal potential. Vertical and lateral resistivity changes were determined from Schlumberger depth soundings with effective probing depths up to 8000 ft. Known geothermal anomalies appear as residual resistivity lows superimposed on the regional gradient that decreases northwestward from the southeast corner of the Imperial Valley, near the Colorado River, to values about two orders of magnitude lower at the Salton Sea. A regional salinity gradient in the Imperial Valley trends northwest from a very low salinity at the Colorado River near Yuma, Arizona, to a very high salinity at the Salton Sea geothermal field. Abrupt changes in salinity exist across the Imperial fault, with salinities being much higher west of the fault. Maximum salinities can be estimated by combining the ground resistivity survey and formation factor-depth relationships compiled from well logs. From a technical point of view, the apparent-resistivity and longitudinal-resistivity maps are nearly identical at a probing depth of 3000 ft. Hence continuous profiling at a Schlumberger AB/2 spacing of 3000 ft should permit an effective, low-cost reconnaissance method for still-unsurveyed areas of the Imperial Valley. (auth)
Research Organization:
Univ. of California, Riverside
Sponsoring Organization:
USDOE
NSA Number:
NSA-29-020477
OSTI ID:
4350479
Journal Information:
Geothermics, v. 1, no. 2, pp. 47-62, Journal Name: Geothermics, v. 1, no. 2, pp. 47-62; ISSN GTMCA
Country of Publication:
Country unknown/Code not available
Language:
English