A MAGNETOTELLURIC INVESTIGATION OF THE SAN-ANDREAS FAULT AT CARRIZO PLAIN, CALIFORNIA

High quality, wide-band magnetotelluric data, were collected along two profiles crossing the San Andreas fault at Carrizo Plain, California for crustal imaging as part of the San Andreas Deep Drilling Project. Two-dimensional inversions of the data indicate that the upper crustal part of the San Andreas fault does not appear here as an anomalously conductive zone. Additionally, a broad resistive zone under the Temblo r Mountains (east of the fault) suggests resistive crystalline or meta morphic rocks may be present here as opposed to the more conducting Fr anciscan assemblage, contradicting the generally-accepted geologic mod el.