Earth Planets Space, Vol. 60 (No. 2), pp. 99-104, 2008LETTER
Yo Fukushima1, Taku Ozawa2, and Manabu Hashimoto1
1Disaster Prevention Research Institute, Kyoto University
2National Research Institute for Earth Science and Disaster Prevention
(Received June 29, 2007; Revised November 18, 2007; Accepted November 22, 2007; Online published February 19, 2008)
The 2007 Noto Hanto earthquake (Mw 6.6) is the first major earthquake in inland Japan since the launch of the Japanese ALOS satellite. Interferometric synthetic aperture radar successfully mapped the coseismic displacements from both ascending and descending orbits in and around the earthquake epicentral region. The line-of-sight displacements toward the satellite from the ascending and descending orbits amount to about 50 and 20 cm, respectively. The interferograms as well as the GPS data of the GEONET network are inverted in order to determine the slip distribution on the source fault. The dip and strike angles of the preferred model are 48° and N51°E, respectively, and its fault slip area reaches the seafloor. The dip angle is not well constrained in our tested range between 40° and 60°. The dominant slip area is located just above the hypocenter, at depths between 4 and 10 km. Many aftershocks seem to have occurred on and around the area of dominant slip.
Key words: Slip distribution, Noto Hanto earthquake, ALOS, PALSAR, SAR interferometry, GEONET, GPS.