2:45 PM - 3:00 PM
[SCG45-17] Operation experiment of the system for seafloor crustal deformation observation system using a buoy
Keywords:seafloor crustal deformation, moored buoy
The observation of seafloor crustal deformation, which combines GNSS positioning and acoustic ranging, is an indispensable tool for investigating large subduction-zone earthquakes such as the Nankai Trough earthquake. However, at present, observations are carried out using ships, and the problem is that the frequency of observations is low.
Our research group has been developed a system using buoys in order to perform continuous observation of seafloor crustal deformation. This system has been installed on a fishery buoy of Kochi Prefecture, which is moored immediately above the submarine station located 32 km off Cape Ashizuri, and has been tested for continuous observation. Observation of seafloor crustal deformation using this system started on March 28, 2018. The acoustic ranging could be carried out continuously for about 6 months, but due to power outages occurring three times, especially in winter, the power supply capacity was improved from December 2019 to March 2020 by increasing the solar panels from 5 to 8, and the amount of storage batteries was doubled; also the power supply system was separated into two systems for a 12V system and a 24V system, respectively. The acoustic ranging has been continued for about 10 months or more since March 12, 2020 after improving the power supply capacity. Therefore, it was confirmed that our system can perform the acoustic ranging measurement continuously as long as power is continuously supplied. However, the satellite communication part is insufficient quality, and acoustic ranging data transmitted to land base stations accounts for only about 60 % of the total. The GNSS positioning and attitude measurement data using a gyro are required for seafloor crustal deformation observation, as well as the acoustic ranging data, but these measurements also had problems, and the period when all data are available was only from August 2020 and January 2021. The accuracy of the seafloor positioning was about several centimeters when we used the data during this period.
Our research group has been developed a system using buoys in order to perform continuous observation of seafloor crustal deformation. This system has been installed on a fishery buoy of Kochi Prefecture, which is moored immediately above the submarine station located 32 km off Cape Ashizuri, and has been tested for continuous observation. Observation of seafloor crustal deformation using this system started on March 28, 2018. The acoustic ranging could be carried out continuously for about 6 months, but due to power outages occurring three times, especially in winter, the power supply capacity was improved from December 2019 to March 2020 by increasing the solar panels from 5 to 8, and the amount of storage batteries was doubled; also the power supply system was separated into two systems for a 12V system and a 24V system, respectively. The acoustic ranging has been continued for about 10 months or more since March 12, 2020 after improving the power supply capacity. Therefore, it was confirmed that our system can perform the acoustic ranging measurement continuously as long as power is continuously supplied. However, the satellite communication part is insufficient quality, and acoustic ranging data transmitted to land base stations accounts for only about 60 % of the total. The GNSS positioning and attitude measurement data using a gyro are required for seafloor crustal deformation observation, as well as the acoustic ranging data, but these measurements also had problems, and the period when all data are available was only from August 2020 and January 2021. The accuracy of the seafloor positioning was about several centimeters when we used the data during this period.