岐阜県坂下町における阿寺断層による段丘面の転移

抄録

The well-known Atera Fault in Gifu Prefecture has long been considered as a big fault that may have produced a marked contrast between the high mountaininous district around Ontake Volcanoes and the southern district of mountains and hills with less higher altitudes.
It was pointed out in 1959 that river terraces in Sakashita have been displaced by recent movement of the Atera Fault. As the result of faulting through Late Quaternary time, a minor but peculiar fault topography in Sakashita is exhibited as shown in Fig. 3 and 4 a. b.
The amounts of displacement of the older terraces are larger than those of the younger terraces.
As correlation of the terraces between both sides of the fault line is not always easy, basic criteria to identify the terraces are discussed with respect to each terrace group. Thus, the amounts of both vertical and lateral displacements. that have taken place through Late Quaternary time are estimated . The radiocarbon dates of the volcanic mudflows building the Takabe terrace indicate their age to be some 27, 000 C¹⁴ years ago (Quat. Res. Group Kiso Valley and Kigoshi, 1964). Vertical and lateral displacement amounting respectively up to some 25m and 80m have taken place since 27, 000 C¹⁴ years B. P.