[HDS11-03] On generation mechanism of the tsunami due to the 1923 Great Kanto Earthquake and bathymetric change in Sagami bay
Keywords:1923 Great Kanto Earthquake, tsunami, submarine landslide, bathymetric change
This report presents the results of a comparison between the reproduction numerical simulation and the recording tsunami height along the coast, and investigates the possibility that the tsunami of the 1923 Great Kanto Earthquake was induced by a large-scale submarine landslide in Sagami Bay based on the bathymetric change data reported by Imperial Japanese Navy. Then, in order to discuss the tsunami generation mechanism of the 1923 Great Kanto Earthquake, the tsunami scale and its arrival time which hit the coast of Sagami Bay are estimated using a simple one-dimensional model (Haugen et al., 2005, Lovholt et al., 2015, Harbitz 1992), and these consistencies are evaluated.
As results, it was confirmed that the bathymetric changes which observed before and after the 1923 Great Kanto Earthquake corresponded to the submarine valleys of the Sagami Bay from the analysis in comparison with the current submarine topographic data. And it was found that the tsunami scale, its arrival time and the location of tsunami source induced by submarine landslide in Sagami Bay were qualitatively consistent with the recording tsunami height by considering the characteristics of the shallow-water deformation and the tsunami convergence.