This paper clarifies the accurate distribution of the Omagari-Toyotomi fault, one of the prominent geological faults in northern Hokkaido, using the high accuracy analyses and the specific characteristics of the geological environments in the Horonobe Town.
In the Kamihoronobe area, the central Horonobe Town, the slight linear landform runs along the border of drainage patterns which reflected the lithology. In addition, the outcrop of fault, the boundary between the Wakkanai and Koetoi formations, situates along the linear landform. Judging from the above description, we conclude that the linear landform shows the Omagari-Toyotomi fault.
In the Hokushin area, the northern Horonobe Town, where the fault doesn't form the lithology boundary and the fault isn't reflected topography, it was found that the result of investigations using the drainage pattern, slight linear landform, the subsurface geological structure, and the number of diatom valves clarify the detailed distribution of the fault.
We will have to clarify the accurate distribution of the fault such as the branch fault and the secondary fault, and in a wide area, with same methods as this study.
