Tectono-geological research on the seismogenic belt along the Japan margin of Amurian Plate

The Present seismotectonic province corresponds with the active fault province, and was formed during the birth term of Honshu Arc. If the crustal strain field was changed, behaviors differ for every province. For a typical example, the 2011 off-Tohoku earthquake showed this vividly, since the induced earthquake occurred along the eastern margin of Amurian Plate. As a postseismic behavior of this mega-earthquake, extensional strain province due to eastward displacement were remarkably observed and is extending from the eastern margin of Japan Sea into the Hokuriku region, north-central Japan. However, no reversal change has been observed in principal-axis arrangement of regional tectonic stress field, and an interesting overlapping of the extensional strain field with the compression state of seismogenic stress field was noticed in the upper crust.