Dense Ocean Floor Network for Earthquakes and Tsunamis Around the Nankai Trough Mega Thrust Earthquake Seismogenic Zone in Southwestern Japan: Real Time Monitoring of the Seismogenic Zone

The Nankai Trough is well known as the mega thrust earthquake generating tsunamis, with the interval of 100–150 years. The 1944 Tonankai and the 1946 Nankai earthquakes around the Nankai trough, each hypocenter was located off the Kii peninsula. Based on structural and simulation researches, we proposed and have been starting to deploy the dense ocean floor observatory network system around the Tonankai seismogenic zone, to monitor crustal activities using broadband seismometer, accelerometer and precise pressure gauges. The ocean floor network is significant ant important to monitor the crustal activities around mega-thrust earthquakes.