It has been thought that the earthquake on November 4, 1856, had caused severe damage to Tokorozawa in the present Saitama Prefecture and Kumegawa and Tachikawa in the present Tokyo Metropolitan Area, Kanto, Japan. The seismic intensities in these areas are evaluated as 5-lower or 5-upper on the Japan Meteorological Agency (JMA) scale and the epicenter was estimated near the above area. However, the severe damage in these areas is relied on a short description in the book of municipal history which was published approximately 100 years after the 1856 event and there are no other historical records describing severe damage in these areas regardless of abundant historical materials in those days. Furthermore, there are several mistakes in the book and this short description is possibly made by a human error during the editing process. Since the short description is doubtful, we investigated whether the severe damage at these areas is recorded in contemporary historical materials that were written in and around the above areas or not. We confirmed that there were no descriptions on the severe damage in these areas in the contemporary historical documents and concluded that the 1856 event did not cause severe damage in these areas and the short description in the book of municipal history is a fake. By comparing the seismic intensity distribution for the 1856 event derived from historical materials with those for various earthquakes in the Kanto district during 1919-2022, the 1856 earthquake was inferred as an M 5.0~6.0 slab or interplate event beneath the area from northern Tokyo Bay to northeastern Saitama and southern Ibaraki Prefectures. The 1856 event is possibly a moderate-sized aftershock or triggered event following the 1855 Ansei-Edo earthquake, although the uncertainty is significantly large due to the sparse distribution of the estimated seismic intensities for the 1856 event.
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