Earth Planets Space, Vol. 56 (No. 2), pp. 103-107, 2004
Hiroshi Yarai1, Taku Ozawa2, Takuya Nishimura1, Mikio Tobita1, and Tetsuro Imakiire1
1 Geography and Crustal Dynamics Research Center, Geographical Survey Institute, Kitasato-1, Tsukuba, Ibaraki 305-0811, Japan
2 Japan Society for the Promotion of Science / Geographical Survey Institute, Kitasato-1, Tsukuba, Ibaraki 305-0811, Japan
(Received November 22, 2003; Revised February 27, 2004; Accepted February 27, 2004)
We applied synthetic aperture radar (SAR) interferometry to map the deformation field of the northern Miyagi earthquake (M6.4) which occurred on July 26, 2003. RADARSAT-1 and ENVISAT satellite data were processed to show the deformation field associated with the earthquake. This is the first observation of the crustal deformation associated with an earthquake detected by ENVISAT SAR interferometry.
The 2.5-dimensional displacement near the epicenter was revealed by the combination of RADARSAT-1 and ENVISAT interferograms. The 2.5-D displacement vectors are consistent with the fault model proposed by Nishimura et al. (2003). The InSAR displacement fields show that the boundary of the uplifted and subsided areas is located not along the Asahiyama flexure but 3-4 km east of the flexure. Therefore, the source fault of the earthquake may have little relation to the Asahiyama flexure.
Key words: Crustal deformation, northern Miyagi earthquake, InSAR, RADARSAT, ENVISAT, 2.5D displacement.