Abstract
In order to solve a mechanical inconsistency that the Osaka Bay basin exists between the Median Tectonic Line (MTL) and Arima-Takatsuki Tectonic Line (ATTL) (right-lateral left-stepping faults), we attempted to investigate and evaluate the basin forming mechanism at the termination of right-lateral left-stepping faults by means of the dislocation modeling.
The results of the numerical simulations show that the sedimentary basin can be formed at the termination of the right-lateral left-stepping faults develop, if the secondary fault caused by the rightlateral motion is a reverse fault and its displacement is larger than 20% of the lateral motion. We applied this model to the fault distribution in the Kinki district, and found that tectonic structures around the Osaka Bay can be explained by combination of 1) the right-lateral motion of the MTL and ATTL and 2) the reverse motion of their secondary faults, i.e., Nara-Toh'en Fault, Ikoma Fault and Rokko-Awaji Fault Systems.
