逆断層の湾曲形態に関する一考察

活断層デジタルデータを活用して

抄録

In contrast to strike-slip faults, relationship among geometrical features and controls on fault rupture, growth, and segment linkage of reverse faults is poorly known although the detailed mapping of active faults and its data on GIS format enable us to analyze characteristics of their surface geometry. It is well known that reverse faults show sinuous surface trace. We analyzed geometric characteristics of 35 major reverse fault zones in Japan based on Digital Active Fault Map of Japan (Nakata and Imaizumi ed.,2002).
We measured distance between both ends on individual fault zone (L) and fault trace (1), and distance from the line connecting the ends to the furthest point on the arcuate zone (H) and the trace (h), and compare their curvature (H/L or h/1). Values of L, H,1 and h were distributed in range of 10∼ 80 km,2∼ 10 km,1∼ 10 km and 0.1 -.5 km respectively. The curvature (H/L) of the reverse fault zones is, regardless their length,0.1∼ 0.3, and that (h/l) of the fault traces is 0.02∼ 0.3, although it is 0.1∼ 0.3 among most of the traces. These results show a fractal-like hierarchy in a curvature of the reverse fault.