Horizontal displacement in the north of the Aratozawa dam caused by the Iwate-Miyagi Nairiku Earthquake in 2008

Abstract

An earthquake-fault-like structure was reported in the north of the Aratozawa dam after the Iwate-Miyagi Nairiku Earthquake in 2008. Horizontal displacements around the structure were measured by photogrammetry. We found 2 rigid blocks on both side of the structure. Comparing with the nearest GPS-based control station (permanent GPS receiving station), we judged that relative displacement between the rigid blocks was caused by the movement of the earthquake fault. Displacements are smoothly varying between the structure and the rigid blocks. Therefore we concluded that the structure is based on the movement of the earthquake fault.