5:15 PM - 6:30 PM
[MIS34-P44] Surface Fault Ruptures of the 2016 Kumamoto Earthquake
Keywords:2018 Kumamoto Earthquake, earthquake fault, active fault
According to 3 weeks field survey by our team, we found the 31-km-length successive surface rupture close to the traces of the northeastern portion of the FHFZ and another the 5-km-length rupture on a part of Denokuchi fault and some possible surface ruptures in the epicentral area. The rupture along the FHFZ shows right-lateral strike-slip mainly (~ 2 m in maximum between Dozon in Mashiki city and Nishihara village) with down-thrown to northwest. The rupture on the Denokuchi fault, far from 1 to 2km east of the FHFZ, is normal component with down to northwest. These coseismic ruptures of the Mj 7.3 earthquake represented a characteristic movement of the northeastern portion of the FHFZ.
A series of the open cracks with NW-SE-trending were traceable for a distance of 5.4 km from Kengun to Shirakawa River in Kumamoto city. Those features followed on tectonic landform by possible active fault and on the line of the fringe abnormal in InSAR image, and may represent minor surface rupture.
The local eyewitness and our observation revealed that the coseismic minor rupture of the Mj 6.5 earthquake prior to the Mj 7.3 earthquake were emerged on the some trace of the rupture of the Mj 7.3 earthquake in Mifune town and South of Mashiki town.