Submarine topography off the Kii peninsula

Abstract

The offshore area around Nankai trough is supposed to be the seismogenic region of the next Tonankai and Nankai earthquakes. Therefore, it is essential to examine carefully submarine topography and active faults in this region. We executed tectonic geomorphological research on the submarine topography with re-analyzed elevation data taken by Japan Coast Guard, which have 3 second resolution. We described here the characteristics of the submarine topography and active tectonics in the area between 134.5 and 137.5 degree, including the Kumano and Muroto troughs. This area has following three characteristic parts. (1)the continental shelf and slope located 10 to 20km off the Kii peninsula, (2)Kumano and Muroto troughs, (3)outer ridge along the Nankai trough. We succeeded to find clear evidences of tectonic activities in every three parts.