17:15 〜 18:45
[MTT37-P06] 稠密な測地データから推定される伊豆衝突帯周辺における地殻変動
The Izu collision zone, characterized by the collision between the Izu-Bonin and Honshu arcs, is located in the northernmost part of the Philippine Sea Plate. Numerous large earthquakes have occurred throughout history, particularly in the northeastern margin of the zone (Ishibashi, 2004 Earth Planets and Space). Moreover, previous studies show that the study area had been highly deformed both in geological and geodetic time scale (e.g., Koyama and Umino, 1991 Journal of Physics of the Earth; Nishimura et al., 2007 Journal of Geophysical Research: Solid Earth). According to our previous analysis result using GNSS, including our original stations, the existence of a shear deformation zone, whose width is about 20 km in EW, in the northeastern part of the Izu Peninsula is shown (Doke et al. 2020, Geological Society of London, Special Publications). However, GNSS station density is still insufficient to understand this complex tectonic field.
In this study, we added about 40 new GNSS stations operated from the end of 2019 by Japan-based telecom and IT operator SoftBank Corp. to the analysis. Moreover, we performed InSAR time series analysis using ALOS-2/PALSAR-2 data to estimate the crustal deformation in and around the Izu collision zone. We are applying the data assimilation method to combine the GNSS and InSAR results to obtain the high-resolved strain rate field.
The estimated strain rate field shows the deformation concentration around the Kita Izu Fault Zone and its brunch faults. Some volcanic areas near the fault zone also show deformations, which imply the existence of a weak zone.
GNSS data from the SoftBank observation network were provided by SoftBank Corp. and ALES Corp. to the “Consortium to utilize the SoftBank original reference sites for Earth and Space Science” under the associated contract. ALOS-2/PALSAR-2 data were provided by JAXA via the Coordinating Committee for the Prediction of Volcanic Eruption as part of the project “ALOS Domestic Demonstration on Disaster Management Application” of the Volcano Working Group. The ALOS-2/PALSAR-2 data belong to JAXA
In this study, we added about 40 new GNSS stations operated from the end of 2019 by Japan-based telecom and IT operator SoftBank Corp. to the analysis. Moreover, we performed InSAR time series analysis using ALOS-2/PALSAR-2 data to estimate the crustal deformation in and around the Izu collision zone. We are applying the data assimilation method to combine the GNSS and InSAR results to obtain the high-resolved strain rate field.
The estimated strain rate field shows the deformation concentration around the Kita Izu Fault Zone and its brunch faults. Some volcanic areas near the fault zone also show deformations, which imply the existence of a weak zone.
GNSS data from the SoftBank observation network were provided by SoftBank Corp. and ALES Corp. to the “Consortium to utilize the SoftBank original reference sites for Earth and Space Science” under the associated contract. ALOS-2/PALSAR-2 data were provided by JAXA via the Coordinating Committee for the Prediction of Volcanic Eruption as part of the project “ALOS Domestic Demonstration on Disaster Management Application” of the Volcano Working Group. The ALOS-2/PALSAR-2 data belong to JAXA