2020 Volume 129 Issue 4 Pages 511-527
One important factor controlling crustal strength is fault zone development. A fault can mature through multiple stages where small faults are generated by rupturing homogeneous media, and are partially connected each other, with large deformations locally concentrated along a major fault. Fault geometry, stress field, and seismic activity, which are detectable with seismic observations, may depend on the stage of fault evolution. At the same time, fault distribution and slip properties observed in a geological survey also provide important information on constraints to fault development. In particular, comparing fault distribution and direction between seismological analyses and geological observations plays an important role in understanding the history of fault zone evolution. A bottleneck in the seismological approach to investigating fault zone development is low spatial resolution due to low spatial density and number of seismic stations. A key element for understanding fault zone development in the crust based on seismic observations is discussed. “0.1 manten” hyper dense seismic observations carried out in the focal area of the 2000 Western Tottori earthquake (M 7.3) are introduced along with the preliminary results of a data analysis.