5:15 PM - 6:45 PM
[STT37-P04] Seismic activity observation with a borehole at the Asakura campus, Kochi University
Keywords:ground acceleration, borehole observatory
In September 2023, Kochi university established a new seismic observatory (New Asakura observatory; tentative name) with a borehole at the Asakura campus (Akebono-cho, Kochi City). We will explain the specifications and the observation conditions of the New Asakura observatory.
Kochi Earthquake Observatory (KEO) of the Kochi University began to observe seismic activities in June 1957 in Ugurusu, Kochi city. In April 1966, it became an educational and research facility affiliated with the Faculty of Literature and Science, Kochi University, and moved to the current location (Asakura hon-machi, Kochi City). Currently, Kochi Earthquake Observatory has a borehole seismometer (SD-112; Katsushima) installed 30 m below the ground surface and a strong-motion seismometers (VSE-11F, VSE-12F; Tokyo Sokushin) installed on the seismometer base.
In 2015, Kochi city office notified that the Kochi Earthquake Observatory should be relocated and demolished to the Kochi university due to the expansion of the Kochi City Urban Planning Road. Sales contract was already signed between the university and Kochi city office on July 2023, and it is scheduled that the building will be demolished in August 2024, and handed over until March 2025 to Kochi city.
Due to the demolition of the Kochi Earthquake Observatory, Asakura observatory has to be relocated. Then, KEO return to its original role as an educational and research facility, and fortifies its educational functions. KEO decides to move in the Asakura Campus. However, the northern rim of the Asakura campus touches the tram tracks and is also close to the JR Shikoku Dosan Line track. In order to compensate observation conditions, we had decided the depth of borehole observation with 200 m. Borehole core samples were fully collected and storage in the Marine Core Research Institute, Kochi University for use as geologically and rock materials in education and research.
Kochi prefecture receives a lot of rain, and most of the homes around Asakura campus use well-water. Thus, to reduce observation environmental impacts by water movements, borehole wall was covered with steel casing and fully cemented outside of casing.
New Asakura campus observatory has an over-damped three components accelerometer (JEP-6B3, 10V/G; Nihon System Industories) was installed at the 192 meters depth. Ground motions signals are extended via analog cables to the server room renovated in the Faculty of Science and Technology Building No. 1, and recorded using with a LT-7700 (Hakusan). Now, we are conducting comparative observations of ground motions at the Asakura observatory and the New Asakura campus observatory
Kochi Earthquake Observatory (KEO) of the Kochi University began to observe seismic activities in June 1957 in Ugurusu, Kochi city. In April 1966, it became an educational and research facility affiliated with the Faculty of Literature and Science, Kochi University, and moved to the current location (Asakura hon-machi, Kochi City). Currently, Kochi Earthquake Observatory has a borehole seismometer (SD-112; Katsushima) installed 30 m below the ground surface and a strong-motion seismometers (VSE-11F, VSE-12F; Tokyo Sokushin) installed on the seismometer base.
In 2015, Kochi city office notified that the Kochi Earthquake Observatory should be relocated and demolished to the Kochi university due to the expansion of the Kochi City Urban Planning Road. Sales contract was already signed between the university and Kochi city office on July 2023, and it is scheduled that the building will be demolished in August 2024, and handed over until March 2025 to Kochi city.
Due to the demolition of the Kochi Earthquake Observatory, Asakura observatory has to be relocated. Then, KEO return to its original role as an educational and research facility, and fortifies its educational functions. KEO decides to move in the Asakura Campus. However, the northern rim of the Asakura campus touches the tram tracks and is also close to the JR Shikoku Dosan Line track. In order to compensate observation conditions, we had decided the depth of borehole observation with 200 m. Borehole core samples were fully collected and storage in the Marine Core Research Institute, Kochi University for use as geologically and rock materials in education and research.
Kochi prefecture receives a lot of rain, and most of the homes around Asakura campus use well-water. Thus, to reduce observation environmental impacts by water movements, borehole wall was covered with steel casing and fully cemented outside of casing.
New Asakura campus observatory has an over-damped three components accelerometer (JEP-6B3, 10V/G; Nihon System Industories) was installed at the 192 meters depth. Ground motions signals are extended via analog cables to the server room renovated in the Faculty of Science and Technology Building No. 1, and recorded using with a LT-7700 (Hakusan). Now, we are conducting comparative observations of ground motions at the Asakura observatory and the New Asakura campus observatory