[M-IS17] History X Earth and Planetary Science

[MIS17-P05] Damage to the Kamo Wakeikazuchi Jinja Shrine and the Seismic Intensity due to the 1830 Bunsei Kyoto Earthquake

*Junzo Ohmura^1,2, Yasuyuki Kano^1,2, kiyomi iwahashi³, Natsumi Kusayama³, Miki HAMANO⁴, Reizaburo Kitai⁵, Munehisa Yamamoto⁶, Harufumi Tamazawa^7,8, Haruo Horikawa⁹ (1.Earthquake Research Institute, The University of Tokyo, 2.Collaborative Research Organization for Historical Materials on Earthquakes and Volcanoes, 3.Kokugakuin University, 4.Graduate School of letters, Ritsumeikan University, 5.Ritsumeikan University, 6.The Foundation of The Kamoagatanushi Clan, 7.Institute of Industrial Science, the University of Tokyo, 8.Kyoto City University of Arts, 9.National Institute of Advanced Industrial Science and Technology)

Keywords:Historical Earthquakes, Kamo Wakeikazuchi Jinja Shrine, Seismic Intensity

On August 19, 1830, an earthquake with a magnitude of M6.5±0.2 occurred, with the epicenter located in the northeastern part of the Kameoka Basin (Usami et al., 2013). This earthquake caused damage throughout the Kyoto Basin. The earthen wall of the Imperial Palace collapsed, and the stone wall of Nijo Castle also collapsed (Estimated seismic intensity: 5+).
The “Shaki Kari-tsuke,” stored at the Kamo Wakeikazuchi Jinja Shrine, records the damage to the shrine and its surroundings caused by the earthquake. The entry for July 2nd reads “Clear, major earthquake,” but there is no record of the situation at the time of the earthquake. The damage in various places is recorded in the results of investigations conducted after the earthquake and in damage reports. It can be seen that the details of the damage were clarified over several days.
The entry for July 4th records the results of an investigation into the places damaged by the earthquake. Also, on the 7th, a concise report summarizing this is posted. The former lists about 30 places where damage occurred, and the latter lists 6 places. According to these, it is written that there was no damage to the buildings of the main shrine, auxiliary shrines, branch shrines, and the shrine and buildings of Kifune Shrine. Including Kifune Shrine, it seems that there was no major damage to the main buildings. On the other hand, the buildings covering the auxiliary shrines and branch shrines are damaged. Although the damage to the walls in various places was minor, some collapsed (Estimated seismic intensity: undetermined to 5-). There are also descriptions of “decayed and damaged” regarding the damage to the roofs of multiple buildings, but it is not clear whether this is due to the earthquake or includes those that had deteriorated beforehand (Estimated seismic intensity: undetermined).
The walls had minor damage such as cracks and falling tiles, and some collapsed significantly (Estimated seismic intensity: less than 5 to 5+). The bridge in the shrine precincts has minor damage (Estimated seismic intensity: undetermined). On the other hand, there is a stone bridge that fell into the river due to the collapse of the stone wall of the gate (Estimated seismic intensity: 6, but judged as a general bridge). The stone walls had stones falling out and parts of the embankment collapsing (Estimated seismic intensity: undetermined to 5+), and other damage includes 90% of the pond embankment collapsing (Estimated seismic intensity: 5). From the above damage, it is estimated that the seismic intensity near the shrine was about seismic intensity 5-.
Kamigamo Shrine is located on a fan-shaped landform. The epicenter of this earthquake is thought to be near Mt. Atago, and assuming the conventional epicenter location and scale, even considering the ground conditions, the seismic intensity of less than 5 is slightly small. In the future, it will be necessary to clarify the characteristics of the ground by examining the underground structure and surface soil at the relevant point, measuring the constant microtremors, etc., and analyze the relationship with the damage.