Geological structure related to the Mienhua Submarine Volcano in southern Okinawa Trough from High-Resolution Sparker Seismic profiles

Located in the northern margin of the southern Okinawa Trough, the Mienhua Submarine Volcano (MSV) is probably formed during the post-collision of the former Taiwan orogeny. The MSV is accompanied by vigorous hydrothermal activities. To understand the related tectonic faults, volcanic intrusions, and hydrothermal activity of the MSV, we have collected several high-resolution sparker seismic profiles surrounding the MSV. Our results show that the east and west sides of the MSV show different features. In the east side, we have found unconformities, high-amplitude seismic reflectors, and acoustic blanking zones. The acoustic blanking zones indicate that hydrothermal fluid has penetrated the strata and migrated upwards and laterally. Many hydrothermal plumes are also found in the water column. In other words, hydrothermal activity is active in the eastern region. In contrast, in the west side of MSV, few unconformities or hydrothermal activities were found. Besides, large-scale mass-transport deposits (MTDs) are formed, possibly due to submarine landslides.