抄録
A nationwide continuous GPS network started in 1994 has clarified instantaneous interseismic crustal deformation of the Japanese islands. A large part of the interseismic deformation is attributed to the interplate coupling on boundaries between subducting plates and continental ones. Modeling of interseismic deformation often uses a concept of “slip-deficit” or “back-slip” which are virtual slip to represent a coupled boundary. Deformation due to sliding on a whole block boundary is often approximated by rigid block motion. However, deviation from the rigid motion may not be negligible depending on geometry of the boundary. In a block-fault model, surface displacement is represented by the sum of rigid motion of tectonic blocks and deformation due to slip-deficit on their boundaries. Many researchers have used these concepts to estimate interplate coupling from the interseismic deformation of the Japanese islands. Geodetic data including triangulation, trilateration, and leveling data have been accumulated in Japan for about 130 years. Comparing these data and GPS data gives us a new insight for seismotectonics of the Japanese islands.
