2019 Volume 58 Issue 5 Pages 315-331
Above the focal area of the 2008 Iwate-Miyagi-Nairiku earthquake (Mj7.2), we discuss the activity of the blind reverse fault by studying the spatial variation in the relative heights of fluvial terraces. We revised the correlation and chronology of the fluvial terraces along the Iwai river. To obtain the spatial variation of uplift in the Pleistocene, we measured the relative heights of fluvial terraces. Crustal movements of the 2008 earthquake were also obtained by comparing airborne LiDAR DEM data sets before and after the earthquake. The geological structure of the Pliocene strata, estimated from the seismic profile and the spatial variation of uplift from the relative height of fluvial terraces, can be explained well by the accumulation of crustal deformation caused by the earthquakes along the fault. From these results, it can be concluded that the relative height distribution of the fluvial terraces is an effective index for investigation of the activity of a blind fault.
