Telluric mapping, telluric profiling, and self-potential surveys of the Dunes Geothermal Anomaly, Imperial Valley, California

The results of the present telluric survey show that the electrical resistivity structure in the region of the Dunes Geothermal Anomaly is complex. Several points are clear, however. The Dunes Geothermal Anomaly is a region of low resistivity, the size and geometry of which were not completely determined. The Dunes Anomaly is probably fault controlled, i.e., polarization and noise analysis suggest that the controlling geological structure is a northwest trending strike-slip fault located in the sand hills. The postulated extension of the San Andreas Fault Zone is a logical possibility. The existence of northeast trending conjugate faulting is not ruled out since it is noted that the gravity high associated with the Dunes Anomaly is actually centered about 2 km northeast of the UCR no. 115 borehole. The Dunes Geothermal Anomaly could be associated with a larger structure centered beneath the gravity maximum. Finally, split spread telluric profiling was found to be a rapid low cost method of geothermal exploration.