PRELIMINARY STUDY ON VOLCANIC CRATER IN THE MIDDLE OKINAWA TROUGH

The Okinawa Trough is a back-are basin located in the eastern East China Sea shelf, and it is thought to be in a nascent rifting stage of back-arc spreading. In the Okinawa Trough, volcanic activities and earthquakes occur frequently, many faults are in the Trough, and also there is abundant pyroclastic sediment. On the basis of the content of pumice and magnetite in marine sediments and combining with the data of water depth, the study result shows that, there is a volcanic crater near core Z 14-5(27°18'N.127°12'E).