VERIFICATION OF ACCURACY OF LIQUEFIED SOIL SUBSIDENCE MAP OF URAYASU FROM AIR-BORNE LIDAR SURVEY AND DISPLACEMENT-INFLICTED DAMAGE TO STRUCTURES AND THEIR SUBSOILS

Abstract

 The 2011 East-Japan Earthquake has caused sand-liquefaction over the long stretch of Tokyo Bay area. Both Konagai laboratory and Aero Asahi Corporation jointly surveyed Urayasu city, one of the heavily liquefied areas, to measure soil/structure subsidence caused by liquefaction. An airborne LIDAR imagery was obtained on April 20th and compared with that before the earthquake. To remove the effect of deepseated tectonic deformations, end-bearing pile supported buildings were taken as a reference. The first half of this paper verifies the accuracy of the map, and the latter half describes displacements that houses and coastal levees have suffered.