2:45 PM - 3:00 PM
[SVC38-40] Magnetotelluric images of Kusatsu-Shirane volcano, revisited by 3-D modeling with tetrahedral elements considered topography effect
Keywords:data inversion, geothermal field, clay, fumerole
The final model presents two major electric conductive structures. A 0.5-3 ohm-m conductive structure with 500-1000 meters thickness is located at 300 meters depth, beneath Yugama crater and extend to the east slope of Kusatsu-Shirane volcano until Sesshogahara fumarole field. Another conductor at the west of Yugama crater has 600-1000 meters thickness at 1500-2000 meters depth.
Comparing the final model with microseismic data, most of the hypocenters are under a low conductive (<2 ohm-m) structure beneath Yugama crater. This conductive structure infers a hydrothermal deposit of volcano, which cut-off the seismicity as a cap rock. At the north of Mizugama crater, a high resistivity structure at the edge of conductor infers the path of fumarole. The deep conductor between Kusatsu-Shirane volcano and Manza geothermal field infers the geothermal source of Kusatsu-Shirane volcano system.