The mountain chain is a part of the complicated structure in
and near Japan with the interaction among Okhotsk, Pacific,
and Eurasia plates (Fig. 1). In contrast to the volcanic activity,
the seismic activity in this region is unexpectedly low
(Fig. 2). This coincides with the small crustal deformation in
the central part of Hokkaido (Tada and Kimura, 1987). The
seismic activity and tectonics have to be investigated more in
detail to understand the complex plate configuration in this
region.
The triangulation survey has been conducted by Geographical
Survey Institute of Japan (GSI). Crustal deformation by
the survey is characterized by the northwestern movement in
the eastern side and by the southeastern in the western side
of the Taisetsu mountains (Tada and Kimura, 1987). This
is generally consistent with the crustal deformation by the
GPS measurement in the surrounding region of the mountain,
which has been conducted by GSI in the last few year
(GSI, 1999).