A large amount of the ground supporting building 70 had been lost by erosion and scour in the past severe typhoon. The big score hole was recently backfilled by air mortar for stabilizing building 70. The change in dynamic characteristics of building 70 was tracked with the increase of backfill material every two hours by the vibration sensor network in Gunkanjima. It is reported that dynamic characteristics of the superstructure varies globally and locally with the progress of backfilling.
