Earth Planets Space, Vol. 60 (No. 2), pp. 95-98, 2008LETTER
Shinzaburo Ozawa, Hiroshi Yarai, Mikio Tobita, Hiroshi Une, and Takuya Nishimura
Geographical Survey Institute of Japan, Tsukuba, Japan
(Received June 8, 2007; Revised September 10, 2007; Accepted October 4, 2007; Online published February 19, 2008)
The Global Positioning System (GPS) network in Japan detected coseismic deformation from the 2007 Noto Hanto earthquake (Mw = 6.9). The result indicates a 21-cm southwestward displacement and a 7-cm upheaval at the GPS site near the epicenter. Synthetic Aperture Interferometry (InSAR) shows an approximately 50-cm movement toward the "Daichi" satellite, in ascending orbit, near the epicenter. The estimated fault slip distribution based on GPS and InSAR results shows a large slip area ranging up to 2 m near and northeast of the hypocenter. The slip area beneath the Sea of Japan southwest of the hypocenter also shows large slippage of around 2 m. Aftershocks are distributed in the asperity area and its vicinity, demonstrating that the asperity hypothesis clearly does not hold completely for this earthquake. Computed vertical displacements using the model are consistent with the geomorphological evidence of long-term uplift.
Key words: Noto Hanto Earthquake, coseismic deformation, GPS, InSAR, coastal terrace.