Velocity field of around the Sea of Okhotsk and Sea of Japan regions determined from a new continuous GPS network data

To investigate the current crustal movements in and around the Sea of Okhot sk and Sea of Japan regions, we have established a continuous GPS network. By the end of 1997, the network had been expanded to include 12 new station s. Data for the period from July 1995 to November 1997 were analyzed togeth er with data from International GPS Service for Geodynamics (IGS) global st ations. To fix the estimated coordinates to the terrestrial reference frame , the Tsukuba IGS station was assumed to be moving westward relative to the stable Eurasian continent at similar to 2cm/yr according to Heki's[1996] e stimate. We find that: (1) stations in the western margin of the Sea of Jap an have eastward velocity vectors, (2) the pole position of the Okhotsk pla te is located near Okha, which reconfirms the Okhotsk micro plate, (3) a pl ate boundary of the Okhotsk and Amurian plates between southen Sakhalin and Hokkaido is suggested.