A linked stress release model for historical Japanese earthquakes: coupling among major seismic regions

A linked stress release model is proposed for the analysis of spatial inter action of earthquake occurrences through stress transfer within a large are a of the Earth's crust. As an example, the model is used for statistical an alysis for the Japanese historical earthquakes in central Japan and offshor e in the Nankai and Sagami troughs with magnitude M greater than or equal t o 6.5 during the period from 1400 to 1997. This area is divided into four s maller regions of roughly comparable size and activity. Based on the Akaike information criterion (AIC), the results demonstrate the existence of coup ling between certain of the regions. With the evidence that the crust may l ie in a near-critical state, this has implications for the possible trigger ing of earthquakes at long distances from the origin event. In particular, we find evidence for the dependence of Nankai trough events on the Chubu/Ki nki triangle region, whose events are themselves dependent on the the Fossa Magna/Sagami trough. Evidence for the validity of the model includes simul ation results indicating that the model had a higher forecast hazard post-1 991 for an event in the Chubu/Kinki triangle region than did models not inc orporating regional coupling.