Wideband Magnetotelluric Measurements across Izu-Oshima Volcano

Abstract

We carried out wideband magnetotelluric (MT) profile measurements in 1989 and 1990 to detect basement of Izu-Oshima volcano, which erupted in 1986. We newly found the difference in basement resistivity, beneath the previously known wide-spread conductor. The eastern basement is resistive. It may be due to older volcanoes, which formed earlier than the present central cone. The older volcanoes actually outcrop at the east coast. On the other hand, the western basement is conductive, suggesting the Miocene formation, the Yugashima Group (altered andesite, basalt and dacite). We also detected another deep conductive layer at several km depth beneath the western part of the profile. © 1992, Society of Geomagnetism and Earth, Planetary and Space Sciences. All rights reserved.