CONSEQUENCES OF STRESS CHANGES FOLLOWING THE 1891 NOBI EARTHQUAKE, JAPAN

Great earthquakes along the Philippine Sea interplate boundary, centra l Honshu, usually rupture a large portion of the Nankai Trough and Sur uga Trough. However, the 1944 Tonankai and 1946 Nankaido earthquakes, the most recent great Philippine Sea events, did not rupture the Surug a Trough. Mogi proposed that strain release from the 1891 Nobi earthqu ake is responsible for the apparently premature northeast termination of the 1944 rupture zone. Using a recently derived fault model of the 1891 earthquake, combined with a suitable rheological model of central Honshu, we quantify both the inland and offshore consequences of the Nobi earthquake. North of the Median Tectonic Line, the co-seismic plu s postseismic stress changes of the Nobi earthquake promoted the failu re of faults which subsequently ruptured in the decades following 1891 . In contrast, along the Philippine Sea interplate boundary, the co-se ismic plus postseismic strain release of the Nobi earthquake during th e decades following 1891 has delayed the anticipated Tokai earthquake by at least 20 yr.