Study of Intra-plate Crustal Deformation before and after the 2011 Tohoku-Oki Earthquake using InSAR and GNSS

Abstract

I have applied Synthetic Aperture Radar analysis to inland earthquakes before and after the 2011 Tohoku-Oki earthquake. Two inland earthquakes before the Tohoku-Oki earthquake are characterized by complex rupture style that strongly reflects crustal heterogeneity associated with late Cenozoic calderas. I further applied InSAR technique to the coseismic displacement of the Tohoku-Oki earthquake and found local subsidence in the volcanic areas along the Ou backbone range. The local subsidence in the volcanoes also can be explained by heterogeneous deformation associated with late Cenozoic calderas. Thus, crustal heterogeneity well documented by geologists prescribes current coseismic deformation of inland earthquakes. To elucidate detailed interseismic crustal deformation in and around the Atotsugawa fault system, I jointly applied InSAR time-series analysis and GNSS velocity field to reduce long wave-length noise, and found that displacement gradient inside the strain concentration zone is not uniform. Further noise reduction would be necessary in the future.