5:15 PM - 6:45 PM
[MTT37-P05] Transient crustal deformation around the Kussharo Caldera, eastern Hokkaido, captured by dense GNSS observation Network
Keywords:GNSS, CSESS, crustal deformation, volcanic event
The Kussharo caldera in eastern Hokkaido has relatively high seismic activity with inland earthquakes and microearthquakes, and the heterogeneous structures, such as the low resistivity. In order to investigate the detailed strain accumulation/release mechanism and evaluate the potential of earthquakes or volcanic activity, Hokkaido University has constructed a GNSS observation network, which composes five continuous and ~15 campaign observation sites. The results show that the Kussharo caldera region has larger contraction strain than the surrounding area during steady-state (interseismic) periods.
From 2021 to 2023, GNSS observation network captured a transient crustal deformation (seems to be an unrest event) in central part of the Kussharo caldera, where composes the Atosanupuri volcanic group. It shows an expansive deformation field that centered west of the active volcano, Atosanupuri. Around this area, surface deformation observations by interferometric SAR have also reported the occurrence of temporary expansion events from 1993 to 1995. Therefore, detailed understanding of the crustal deformation field and estimation of the source of the deformation are necessary to monitor the process of volcanic activities.
In conjunction with the GNSS observations conducted in September each year at Hokkaido University's campaign network, we obtained and processed RINEX data at ~35 sites around Kussharo Caldera, from 2020 to 2023, which within the framework of the Consortium to utilize the SoftBank original reference sites for Earth and Space Science (CSESS). As a result, yearly detailed crustal deformation fired with high-special resolution are captured at this region. It is also confirmed that the crustal deformation errors obtained from GEONET and CSESS are almost the same.
Using information on the deformation sources of the 1990s event estimated in previous studies, we tried to explain the two-year expansion deformation by assuming sill and Mogi sources, and estimated a volume change on the order of 107m3. This is slightly smaller than that of the 1990s event. The CSESS data will be used to process continuous data to improve the temporal resolution in addition to the high-spatial resolution in this area. It advances detailed crustal deformation analysis and deformation modeling due to seismic activity and subsurface structure.
Acknowledgments: We used GEONET data provided by the Geospatial Information Authority of Japan (GSI). The SoftBank's GNSS observation data used in this study was provided by SoftBank Corp. and ALES Corp. through the framework of the "Consortium to utilize the SoftBank original reference sites for Earth and Space Science (CSESS)". This study was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, under its The Second Earthquake and Volcano Hazards Observation and Research Program (Earthquake and Volcano Hazard Reduction Research), and funded by Earthquake Research Institute, the University of Tokyo, Joint Research program 2023-B-02.
From 2021 to 2023, GNSS observation network captured a transient crustal deformation (seems to be an unrest event) in central part of the Kussharo caldera, where composes the Atosanupuri volcanic group. It shows an expansive deformation field that centered west of the active volcano, Atosanupuri. Around this area, surface deformation observations by interferometric SAR have also reported the occurrence of temporary expansion events from 1993 to 1995. Therefore, detailed understanding of the crustal deformation field and estimation of the source of the deformation are necessary to monitor the process of volcanic activities.
In conjunction with the GNSS observations conducted in September each year at Hokkaido University's campaign network, we obtained and processed RINEX data at ~35 sites around Kussharo Caldera, from 2020 to 2023, which within the framework of the Consortium to utilize the SoftBank original reference sites for Earth and Space Science (CSESS). As a result, yearly detailed crustal deformation fired with high-special resolution are captured at this region. It is also confirmed that the crustal deformation errors obtained from GEONET and CSESS are almost the same.
Using information on the deformation sources of the 1990s event estimated in previous studies, we tried to explain the two-year expansion deformation by assuming sill and Mogi sources, and estimated a volume change on the order of 107m3. This is slightly smaller than that of the 1990s event. The CSESS data will be used to process continuous data to improve the temporal resolution in addition to the high-spatial resolution in this area. It advances detailed crustal deformation analysis and deformation modeling due to seismic activity and subsurface structure.
Acknowledgments: We used GEONET data provided by the Geospatial Information Authority of Japan (GSI). The SoftBank's GNSS observation data used in this study was provided by SoftBank Corp. and ALES Corp. through the framework of the "Consortium to utilize the SoftBank original reference sites for Earth and Space Science (CSESS)". This study was supported by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan, under its The Second Earthquake and Volcano Hazards Observation and Research Program (Earthquake and Volcano Hazard Reduction Research), and funded by Earthquake Research Institute, the University of Tokyo, Joint Research program 2023-B-02.