Japan Geoscience Union Meeting 2023

Presentation information

Poster

O (Public ) » Public

[O-06] Poster presentations by senior high school students

Sun. May 21, 2023 1:45 PM - 3:15 PM Poster (Exhibition Hall 8, Makuhari Messe)

convener:Tatsuhiko Hara(International Institute of Seismology and Earthquake Engineering, Building Research Institute), Katsuyoshi Michibayashi(Department of Earth and Planetary Sciences, Nagoya University), Miwa Kuri(Japan Meteorological Agency), Keiko Konya(Japan Agency for Marine-Earth Science and Technology)

On-site poster schedule (2023/5/21 13:45-15:15)

1:45 PM - 3:15 PM

[O06-P83] Change of damage to shrines and temples or houses from historical tsunamis

*Sumire Unosawa1 (1. Sakaehigashi High School)

Keywords:historical tsunamis, temples and shrines, the proportion of washed away, rebuilding


It is often the case that many temples and shrines are damaged from tsunamis because they are hundreds of years old, and they have been rebuilt in same areas. I think if they are rebuilt in higher places than before, they will get damaged less from tsunamis in the future. In addition, I also suppose that shrines and temples are damaged less from tsunamis than buildings such as houses and warehouses because they are newer than shrines and temples. I tried to prove these hypotheses in two ways. First, I considered the proportion of washed away shrines and temples in each earthquake. Second, I compared the proportions of washed away shrines and temples to washed away houses. In these ways I focused four areas:Taro and Omoe in Miyako City, Yamada Town in Iwate Prefecture and Kamakura City in Kanagawa Prefecture. I focused on shrines and temples in the Genroku Earthquake and the Kanto Earthquake, and the shrines in Taro, Omoe and Yamada Town in the Meiji Sanriku Earthquake, the Showa Sanriku Earthquake and the Tohoku Earthquake.
Firstly, in Kamakura City, the proportion of washed away temples and shrines was less than that of washed away houses in the Kanto Earthquake(Table1・Table2・Graph1). This fact proves the hypothesis of mine that shines and temples have less damage from tsunamis than houses. In addition, the proportion of washed away shrines and temples in the Kanto Earthquake was lower than that of the Genroku Earthquake. This is not only because Enoji Temple was rebuilt in a higher place but also because the size of the Kanto Earthquake was smaller than the Genroku Earthquake. Therefore, I could not conclude that the reason why the proportion of washed away shrines and temples was lower just because they were rebuilt in higher area.
Secondly, in Yamada Town the proportion of washed away houses and shrines in the Tohoku Earthquake was higher than in the Showa Sanriku Earthquake(Graph2). However, in Taro in Yamada City there were no washed away shrines in the Showa Sanriku Earthquake(Graph3). I think the difference between the proportion of washed away shrines between Yamada Town and Taro was because of the more severe damage from tsunamis in the Meiji Sanriku Earthquake in Taro than in Yamada Town. However, because I could not find the detailed records of the damage from tsunamis to shrines in the Meiji Sanriku Earthquake, it is a mystery. In Omoe in Miyako City the proportion of washed away shrines was higher than that of washed away houses in the Showa Sanriku Earthquake(Graph4). This is mainly because the damage to the shrines was exaggerated due to the small number of shrines in Omoe. In addition, because it seems strange that the shaden of Shinshi Shrine was washed away in the Showa Sanriku Earthquake in my hypotheses(Table3), I have to search for whether the shrine was rebuilt or not.
From the above, the proportion of washed away temples and shrines depends on the size of the earthquake(Graph5), and I could not conclude if the proportion of washed away temples and shrines declines because temples and shrines were damaged from tsunamis many times. However, I found that the proportion of washed away temples and shrines tends to be lower than that of washed away houses. In addition, even if the proportion of washed away temples and shrines is higher than before, it is still lower than the maximum number of the proportion of washed away houses in the earthquakes which I focused on in this research.
In next steps I will use not only the proportion of washed away buildings but also the proportion of damage including flooding or destroyed. Also, I am going to survey more areas in Iwate Prefecture and increase the number of the houses and shrines because the records of the damage from the tsunamis in the Showa Sanriku Earthquake and the Tohoku Earthquake.