[J02-P] Poster

[J02-P-04] Crustal deformation of the 2016 Kumamoto earthquake sequence (3) - Small displacement linear surface ruptures detected by ALOS-2 SAR -

^○Satoshi Fujiwara, Hiroshi Yarai, Tomokazu Kobayashi, Yu Morishita, Takayuki Nakano, Basara Miyahara, Hiroyuki Nakai, Yuji Miura, Haruka Ueshiba, Yasuaki Kakiage, Hiroshi Une (GSI of Japan, Tsukuba, Japan)

We constructed and analyzed the ground surface displacement associated with the 2016 Kumamoto earthquake sequence using satellite radar interferometry images of the Advanced Land Observing Satellite 2. The radar interferogram generally shows elastic deformation caused by the main earthquakes but many other linear discontinuities showing displacement are also found. Approximately 230 lineaments are identified, some of which coincide with the positions of known active faults, such as the main earthquake faults belonging to the Futagawa and Hinagu fault zones and other minor faults; however, there are much fewer known active faults than lineaments. In each area, the lineaments have a similar direction and displacement to each other, therefore, they can be divided into several groups based on location and major features. Since the direction of the lineaments coincides with that of known active faults or their conjugate faults, the cause of the lineaments must be related to the tectonic stress field of this region. The lineaments are classified into the following two categories: (1) main earthquake faults and their branched sub-faults; and (2) secondary faults that are not directly related to the main earthquake but whose slip was probably triggered by the main earthquake or aftershocks.