Abstract
Many landslides occurred during the 2011 off the Pacific coast of Tohoku Earthquake (Mw9.0) . Among them, the most catastrophic one occurred in Hanokidaira Area, Shirakawa City. There are two permanent strong motion observation stations nearby, but they showed significant difference in their main shock observation records. To better understand the initiation mechanism of this landslide, it is necessary to have a better understanding on the seismic response of the landslide area during the main shock with high accuracy by taking into account site effects. Therefore, in this study, we estimated the seismic waveform at the Hanokidaira landslide basing on the site effects substitution method that has been identified to be a promising tool for inland earthquakes. We monitored the aftershocks on Harokidara landslide area, and then the site effects at Hanokidaira landslide area have been evaluated. Through this study, we also validated the applicability of the method to a huge subduction earthquake basing on strong motion records. We found that the difference of the site effects between Hanokidaira landslide and those two permanent observation stations is significant.
