| We conducted a detailed near-surface geophysical survey and hearing survey of housing damages at Yasunaga District, Mashiki Town stricken by the 2016 Kumamoto Earthquakes. The geophysical survey comprised “Hybrid Surface Wave Survey” (HSWS), capacitively coupled resistivity (CCR) measurement, and GPR. A 350 m long short survey line was deployed along a road between Route 28 and Akitsu River. Hearing survey was also conducted along the survey line. We directly interviewed with residents in May 2018, or indirectly inspected housing sites. Both resistivity and S-wave velocity sections delineated a thick low resistivity and low Vs layer occupied the surfaces at the southern half of the line, or Akitsu lowland area. A total of 31 dwellings were surveyed supported by board members of the Yasunaga District community. The hearing was quite helpful to understand local anomalies of ground failure caused by the Earthquakes. The survey results strongly suggested that surface failures occurred in Yasunaga District mainly resulted from non-tectonic deformations. |
