DAMAGE MECHANISMS OF MOUNTAIN TUNNELS IN THE 2007 NIIGATA CHUETSU-OKI EARTHQUAKE: INSIGHT FROM SAR INTERFEROMETRY

Abstract

  Mountain tunnels damaged in the 2007 Chuetsu-oki earthquake were localized around the Tochikubo anticline, 30km southwest of the epicenter, although the tunnels near the epicenter were not much damaged. To examine a behavior of deformation around the damaged tunnels, we analyzed SAR interferometry and mapped the surface displacements associated with the 2007 earthquake. The estimated surface displacements reveal uplift deformation at the Tochikubo anticline. We interpret that the damages to the mountain tunnels were caused by flexural-slip due to uplift of the Tochikubo anticline or amplification of ground vibration due to earthquake directivity.