Geomorphic response to active strike-slip faulting in Japanese mountains: quantitative analyses of channel offsets using LiDAR DEMs

We analyzed the relationships between channel offsets and other geomorphic properties to evaluate the geomorphic response to active strike-slip faulting in Japanese mountains. Eight active strike-slip faults with various slip rates ranging from ~0.01 mm/yr to ~10 mm/yr were examined using airborne LiDAR (Light Detection and Ranging)-derived high-resolution DEMs (Digital Elevation Models). Channel offsets were automatically extracted by introducing a threshold of deflection degree, which allows us to distinguish tectonic channel offset from non-tectonic fluctuation of channel flow. Relationships between channel offsets and geomorphic properties, such as channel length, drainage area and slope angle, were assessed to obtain certain connections between the geomorphic properties and slip rates. Our study may provide a new approach for quantitatively assessing activities of the strike-slip faults with no chronological information such as those in mountainous and arid regions.