抄録
The co-seismic crustal uplift more than 15 centimeters associated with the 1982 Urakawa-oki earthquake, which occurred in the Hidaka region, Hokkaido, Japan, were observed by the leveling survey. Fault parameters of the 1982 Urakawa-oki earthquake were estimated from the crustal uplift data referring to the earthquake mechanism and the hypocenter distributions. Estimated fault parameters are as follows: type, reverse; length, 18km; width, 23km; dip angle, 30°; depth of upper margin, 18.5km; dip direction, NE; slip direction, WSW; dislocation, 160cm.
The fault parameters mean that the Hidaka mountains have thrust up to the WSW direction. This fault motion is identical with the idea that the Kuril outer arc have drifted to the west and collided against the Central Hokkaido at the southwestern margin of itself.
Pre-seismic uplift detected by the leveling survey and the tide observation suggests that the precursor began at about three years before the earthquake. This gives a useful key of the prediction of earthquakes which will occur in and around the Hidaka region in feature.
