Japan Geoscience Union Meeting 2023

Presentation information

[E] Oral

S (Solid Earth Sciences ) » S-RD Resources, Mineral Deposit & Resource Exploration

[S-RD24] Cutting-edge sensing technology applied to geology and resource exploration

Wed. May 24, 2023 3:30 PM - 4:45 PM 106 (International Conference Hall, Makuhari Messe)

convener:Yukihiro Takahashi(Department of Cosmosciences, Graduate School of Science, Hokkaido University), Muhammad Burhannudinnur(The Indonesian Association of Geologist), Decibel Villarisco Faustino-Eslava(Geological Society of the Philippines), Mohd Hariri Arifin(Universiti Kebangsaan Malaysia), Chairperson:Yukihiro Takahashi(Department of Cosmosciences, Graduate School of Science, Hokkaido University)

3:30 PM - 3:45 PM

[SRD24-01] Outline of sustainable research for the conservation and utilization of Underground Built Heritage "Taya Cave"

*Yasuhiko TAMURA1, Chiaki T. Oguchi3, Yuichi S. Hayakawa2, Takuro Ogura4 (1.The Executive Committee for the Preservation of TAYA CAVERN , 2.Faculty of Environmental Earth Science, Hokkaido University, 3.Graduate School of Science and Engineering, Saitama University, 4.Graduate School of Education, Hyogo University of Teacher Education)

Keywords:TLS, SfM, UAV, LiDAR, Underground Built Heritage, Taya Cave

Analysis using advanced technology has been widely used in the humanities, such as history and archaeology, and digital analysis is becoming indispensable. Especially in the field of Underground Built Heritage (UBH), it is essential to conduct research not only on archaeological materials but also on natural sciences such as geology, internal and external environment, and topography. When considering the conservation of UBH, understanding the weathering mechanisms of the constituting geomaterials that makes up the space is essential for making future damage estimates. It is important to conduct various analyses and tests on the geology to be investigated to understand the rock properties, as well as to monitor and acquire data on the internal and external environmental conditions on a regular basis. Furthermore, structural analysis of the geometry of the underground space and the microtopography of the ground is essential. Understanding the thickness of the soil cover from the underground space to the surface and detailed measurements of wall and floor thicknesses between each space in the ground are important spatial structural investigations to understand and predict the sustainability of the UBH. Since these surveys require integrated multidisciplinary survey techniques using a variety of measuring and surveying instruments, it is important that survey research teams be formed to conduct them.
This presentation will discuss about the overview of the research in the field of natural science at Taya Cave, an Underground heritage site registered as a historical site by Yokohama City. This cave is located in a small "satoyama" in Taya-town, Sakae-ku, in the southern part of the city.
Taya Cave has a total length of 570 meters, a three-stories, 11 domes, and more than 200 reliefs on the walls and ceilings, making a full man-made UBH site.
The Taya Cave is a cave for training Shingon Mikkyō ("Buddhism") located underground in a small satoyama called "Taya Mountain" in the precincts of Shingon sect's Jōsen-ji temple.
The authors formed a team in 2017 to conduct research and studies for the conservation and utilization of this cave. To understand the weathering mechanism of the geology (lithology), it is conducted geological, internal, and external temperature and humidity, CO2, color measurement of cave walls, water quality, mechanical destructive testing, and nondestructive testing. For understanding the spatial structure, UAV/SfM, TLS, LiDAR surveys, etc. are being conducted inside and outside the cave. The results of previous research studies have shown that conditions in the caves are possibly influenced by climate change and that the risk of deterioration and deformation due to weathering is on the increase. In addition, in recent years, typhoons and heavy rains have changed the shape of the ground surface, such as trees toppling over. This has revealed that the environment surrounding this UBH is changing.
For UBH conservation, these studies need to continue indefinitely, but the current researchers cannot continue to be involved under a limited small budget. Therefore, the authors believe that the various data obtained from these research studies should be shared with local people around this cave, but that it is important to monitor by local people themselves in the future if possible to do. In particular, it is essential for Josenji-temple, the administrator of this cave. However, there are various barriers to sharing highly specialized data with the public. The first barrier is the need for expensive software and devices to read various types of data. The second barrier is the need for scientific knowledge of how to read the data. For the sustainable preservation of a large cultural heritage site like UBH, it is difficult to resolve these two major problems. This presentation will suggest an original overview of UBH's sustainable research methodology and other future developments.