Japan Geoscience Union Meeting 2016

Presentation information


Symbol M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS34] The 2016 Kumamoto Earthquake and related crustal activities

Wed. May 25, 2016 9:00 AM - 10:30 AM Convention Hall A (2F)

9:35 AM - 9:55 AM

[MIS34-03] Crustal deformation of the 2016 Kumamoto Earthquake

★Invited papers

*Hiroshi Yarai1, Tomokazu Kobayashi1, Yu Morishita1, Satoshi Fujiwara1, Hiroshi Munekane1, Yohei Hiyama1, Satoshi Kawamoto1, Basara Miyahara1, SAR Analysis Group1, GEONET Analysis Group1 (1.Geospatial Information Authority of Japan)

Keywords:The 2016 Kumamoto Earthquake, crustal deformation, GNSS, SAR

Coseismic deformation derived from the 2016 Kumamoto Earthquake was observed by GNSS stations of the permanent GPS Earth Observation Network system (GEONET) and ALOS-2/PALSAR-2 interferometric SAR.
Clear coseismic displacements due to the Kumamoto earthquake were observed by GEONET. NE displacement of 75 cm and subsidence of 20 cm and SW displacement of 97 cm and uplift of 28 cm were detected at sites 0465 and 0701, which are located near the Futagawa fault zone, respectively.
We have also successfully detected distributed ground displacements for the Kumamoto Earthquake by applying a SAR interferometry analysis of Advanced Land Observing Satellite 2 (ALOS-2) L-band data. The interferograms suggest that fault motion of the main shock has right-lateral motion on the Futagawa fault and the Hinagu fault.

We invert the InSAR results with GNSS data to construct a fault model of the earthquake. A fault model consists of 3 rectangular faults with a uniform slip in an elastic half-space. The fault model shows that: a total major rupture length is about 35 km; a total moment magnitude is 7.07.

Postseismic deformation following the Kumamoto earthquake was detected by GEONET and ALOS-2 InSAR. Postseismic deformation up to 3 cm also has been observed by GEONET, showing a roughly similar deformation pattern to those associated with the mainshock. ALOS-2 interferograms show that subsidence about ~5 cm along the Futagwa fault zone.

The PALSAR-2 data obtained by the ALOS-2 were provided by the Japan Aerospace Exploration Agency (JAXA) through the Agreement between GSI and JAXA. The ownership of PALSAR-2 data belongs to JAXA.