Stress, occurrence rates and b-value on the Nankai megathrust system inferred from earthquake simulation

We aim to improve our comprehension of the seismic process and to identify possible long- term predictability tools of strong earthquakes through the simulation performed by a new- generation simulator code based on a well-elaborated model of the earthquake sources. We applied our previously tested physics-based earthquake simulator to the Nankai megathrust fault system, characterized by a 13-century historical record of strong earthquakes. Our results show these significant seismicity patterns characterizing the seismic c ycles: the av erage stress increases almost linearly, while its standard deviation decreases more and more rapidly as the next major earthquake approaches; the coseismic stress drop and the simultaneous increase of the standard deviation mark the beginning of the new seismic cycle; and the b -value tends to increase some decades before major earthquakes and exhibits correlation with the occurrence rate. Our results encourage further investigations into the application of simulators in support of other methodologies of earthquake forecasting.