GLOBAL POSTSEISMIC STRESS DIFFUSION AND FAULT INTERACTION AT LONG DISTANCES

The issue of remote triggering of earthquakes and of fault interactions at great distances have received much attention in the scientific literature of the last years. The idea was thrown out by Romanowicz (1993) who suggested that the pattern of seismic energy release was characterized by alternating periods of prevalent strike-slip and dip-slip activity at the opposite margins of the pacific ring. Though subsequent investigations have shown that the proposed correlation has a large probability to be observed by chance (Johnsons and Sheridan, 1997), the debate on the remote triggering of earthquakes is far from being ended since new evidences have been put forward. Pollitz et al. (1998) have addressed for the first time the problem of the interaction between earthquakes at great distances in a work based on a theoretical model. They studied the pattern of the deformation rate field associated with the great earthquakes which occurred during the fifties and the sixties in the Alaska region and its spatio-temporal correlation with the seismic activity in the north Pacific area. Their conclusions suggested that exists a correlation between the maximu