Advanced ocean floor network system for mega thrust earthquakes and tsunamis

In the Nankai trough located off south western Japan, there are three megathrust earthquake seismogenic zones such as the Tokai, Tonankai and Nankai seismogenic zone. The Nankai Trough is well known as the mega thrust earthquake generating tsunamis, with the interval of 100-200 years. We proposed and have been starting to deploy the dense ocean floor observatory network system around the Nankai trough to monitor crustal activities using broadband seismometer, accelerometer and precise pressure gauges. Furthermore, the ocean floor network data will contribute to improve early warning system, and the recurrence cycle simulation model of megathrust earthquake by data assimilation using real time monitoring data from DONET. The development and deployment of ocean floor network is very important, then the application of data from ocean floor networks is more important to understand the next megathrust earthquake and to make a proposal of disaster measures.