STRONG MOTION CHARACTERISTICS IN THE VICINITY OF SURFACE FAULT RUPTURE AT SUBURBS OF MASHIKI TOWN DUE TO THE 2016 KUMAMOTO EARTHQUAKE

Abstract

 Aftershock and microtremor observations were conducted in the vicinity of surface fault ruptures at suburbs of Mashiki town due to the 2016 Kumamoto earthquake. Our target of the observations is searching out the difference of ground motions between surface faulting areas without severe damages and severely damaged areas without surface faulting. From aftershock observation, ground motion at damaged site is larger than that at surface faulting site without damage, however, average difference of JMA seismic intensity between the two sites are less than 0.5 while estimated difference from witness and real damage is more than 1.0. From microtremor observations, H/V spectra at surface faulting regions are rather flat and do not to have steep peak while clear peaks are observed around the faulting areas.