Proper

Abstract

On March 11, 2011 the Megathrust earthquake occurred at the subduction zone between the Pacific and North American tectonic plates. There was some coseismic mass redistribution as a result of the largest earthquakes and the hidden geophysical signals from the earthquake were investigated via a multiscale wavelet analysis. In the medium-to-short-wavelength part, the coseismic geoid decrease was detected at the northwestern part of the Japan Island in March 2011. With regard to the postseismic geoid recovery, changes at the eastern part of northern Honshu and the southern part of the Sanriku segment were predominant in August 2011. This study concluded that the geological relationship among these locations played a very important role in the Megathrust earthquake occurrence.