Permalink : http://hdl.handle.net/2115/88554

JaLCDOI : 10.14943/gbhu.86.1

Long-term post-seismic crustal deformation characteristics in southwestern Hokkaido induced by the 2003 Tokachi-oki earthquake (Mw 8.0) were investigated using the F5 GNSS daily coordinate data. Comparison of the detrended coordinate time series before and after the 2003 Tokachi-oki earthquake indicated that post-seismic horizontal deformation exceeded co-seismic displacements and continued at least 7.5 years until the day of the 2011 off the Pacific coast of Tohoku earthquake (M9.0). Viscoelastic subsurface models were examined to fit to observed horizontal displacement time series. Parameters of elastic layer 20～30km and viscosity 1×1018 Pa s well reproduced features of observed displacement time series. Estimated coefficient suggest relatively low viscosity in southwestern Hokkaido and was well consistent with that from previous studies in this region.