The Every Earthquake a Precursor

quake forecasting model has been shown to be informative in several seismically active regions, including New Zealand, California and Japan. In previous applications of the model, the tectonic setting of earthquakes has been ignored. Here we distinguish crustal, plate interface, and slab earthquakes and apply the model to earthquakes with magnitude M≥4 in the Japan region from 1926 onwards. The target magnitude range is M ≥ 6; the fitting period is 1966-1995; and the testing period is 1996-2005. In forecasting major slab earth-quakes, it is optimal to use only slab and inter-face events as precursors. In forecasting major interface events, it is optimal to use only inter