[M-IS09] Weathering and conservation of cultural heritage and geosites

[MIS09-P02] Relationship between carbon dioxide concentration and temperature in the Taya cave

*Chiaki T. Oguchi¹, Rina Matsumoto², Yasuhiko TAMURA³ (1.Institute for Environmental Science and Technology, Graduate School of Science and Engineering, Saitama University, 2.Faculty of civil Engineering, Saitama University, 3.Executive Committee for the Preservation of TAYA CAVERN)

Keywords:Taya Cave, CO2 concentration, Temperature

The Taya Caves, an artificial hand-dug cave in the Josenji Temple in Yokohama City, originated in the Kamakura period as one of the worship places of Shingon Esoteric Buddhism. Many people are still visiting the cave. There remains still questions about how 800m of tunnels were manually dug in the dark and narrow spaces of the ground when there were no large tools. A torch should have been lit in the dark, however, there must be a ventilation pit to prevent oxygen deficiency. No such pit is found. Further, it is known that CO2 concentration also increases due to bacterial activities in the underground environment.In this study, we will examine the causes of the increase in CO2 concentration due to the continuation of temperature and humidity monitoring inside and outside the cave, daily changes in the number of visitors, and changes in CO2 concentration. From the correlation between the daily maximum temperature and the CO2 concentration, and the correlation between the temperature at each site and the CO2 concentration, it is expected that the increase in temperature may cause the increase in the CO2 concentration.