Fault model of the 2005 Fukuoka-ken Seiho-oki earthquake estimated from coseismic deformation observed by GPS and InSAR

Abstract

On 20 March 2005, the Fukuoka-ken Seiho-oki (the 2005 West off Fukuoka Prefecture) earthquake (MJMA 7.0) occurred in northern Kyushu, western Japan. We used coseismic deformation observed by GPS and InSAR to construct a fault model. The uniform slip model of rectangular dislocation in an elastic half-space suggests ∼1.4 m of left-lateral strike slip faulting on a near-vertical fault. The fault strike is 298 degrees and its southeastern edge was strongly constrained by the displacement at a permanent GPS station located on Shikanoshima, which is consistent with the aftershock distribution. We estimated slip distribution on a planar fault and found the maximum slip of ∼1.9 m near the surface. Large slip is concentrated at depths of 0 to 10 km in an along-strike range from the hypocenter to 10 km east-southeast of it. Copyright © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS); The Seismological Society of Japan; The Volcanological Society of Japan; The Geodetic Society of Japan; The Japanese Society for Planetary Sciences; TERRAPUB.