5:15 PM - 6:45 PM
[SGD02-P07] Estimation of long-term deformation in Japan using active faults data
Keywords:Active faults, Crustal deformation, Strain
Complex crustal movements occur due to plate motions, plate locking, earthquakes, and volcanic activities in Japan. Crustal deformation consists of elastic and inelastic deformation. Elastic deformation accumulates and releases with the occurrence of earthquakes, on the other hand, inelastic deformation accumulates strain and forms landforms over a long period.Active faults are the result of inelastic deformation. Inelastic strain rates were obtained using active fault data by Wesnousky et al. (1982) and Shen Tu et al. (1995). On the other hand, GNSS observations have been well developed in Japan and conducted before and after the 2011 Tohoku earthquake. Then Meneses-Gutierrez and Sagiya (2016) found localized inelastic deformation from GNSS observations. It is difficult to compare strain rate distributions from active fault data in previous studies with the current study because the data handled are old and the spatial resolution is insufficient in the previous one.In this study, we use the latest active faults data. We obtain long-term strain rates for the Japanese Islands with sufficient spatial resolution. In this study, we used data of the location, strike and dip, fault type, and average displacement velocity of active faults from the Active Fault Database of the National Institute of Advanced Industrial Science and Technology (AIST).
We set up a grid of equally spaced grid points in the Japanese area. We gave the grid points the displacement velocity of each fault, and calculated the strain velocity for each small region from the velocity of the grid points. Then using the strain velocities of the small areas, we averaged them over a larger area to compare them with the results of existing studies and discuss. Further studies are needed, including consideration of marine terrace topography in Japan.
We set up a grid of equally spaced grid points in the Japanese area. We gave the grid points the displacement velocity of each fault, and calculated the strain velocity for each small region from the velocity of the grid points. Then using the strain velocities of the small areas, we averaged them over a larger area to compare them with the results of existing studies and discuss. Further studies are needed, including consideration of marine terrace topography in Japan.