10:45 〜 12:15
[SGD02-P01] GNSSとInSARによる伊豆衝突帯周辺地域における歪速度場の推定
キーワード：地殻変動、GNSS、InSAR、伊豆衝突帯、歪速度
The Izu collision zone, characterized by the collision between the Izu-Bonin arc and the Honshu arc, 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). From our previous analysis result using GNSS, a shear deformation zone, whose width is about 20 km in EW, exists in the northeastern part of the Izu Peninsula (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 performed GNSS and InSAR analysis to estimate the crustal strain rate field in and around the Izu collision zone. To calculate the high-resolved strain field, we combined E-W components obtained from the 2.5-D analysis result of InSAR time series analysis of ALOS-2/PALSAR-2 data and N-S components of GNSS velocity data that were spatially interpolated.
The estimated crustal strain rate field, whose output resolution is 100 m, shows not a homogeneous deformation zone but the existence of some patch-like deformation concentrated zones. Some of the deformation zones may be related to the volcanic activities in this region (Hakone and Higashi-Izu volcanoes). The other deformation zones spatially correspond well with the branch faults of the active Kita-Izu fault zone, which is the source fault of the 1930 Kita-Izu earthquake (M7.0). Therefore, this result shows the strain concentrations and possibilities of earthquake occurrences on these branch faults.
In this study, we performed GNSS and InSAR analysis to estimate the crustal strain rate field in and around the Izu collision zone. To calculate the high-resolved strain field, we combined E-W components obtained from the 2.5-D analysis result of InSAR time series analysis of ALOS-2/PALSAR-2 data and N-S components of GNSS velocity data that were spatially interpolated.
The estimated crustal strain rate field, whose output resolution is 100 m, shows not a homogeneous deformation zone but the existence of some patch-like deformation concentrated zones. Some of the deformation zones may be related to the volcanic activities in this region (Hakone and Higashi-Izu volcanoes). The other deformation zones spatially correspond well with the branch faults of the active Kita-Izu fault zone, which is the source fault of the 1930 Kita-Izu earthquake (M7.0). Therefore, this result shows the strain concentrations and possibilities of earthquake occurrences on these branch faults.