**3. Neotectonic domains in southwest Japan**

The authors have presented the characteristics of major neotectonic zones (lines) around the eastern part of southwest Japan. Next, we attempt to describe neotectonic domains bordered by these features. We identify the Chugoku, Kinki and Chubu domains from west to east (Figure 1).

The Chugoku domain is characterized by quite broad dextral wrenching and inactive basin formation. It is a crust sliver between the MTL and the Southern Japan Sea Fault Zone (SJSFZ). The SJSFZ is a reactivated right-lateral fault along the late Miocene backarc inversion zone [36]. Itoh and Takemura [7] pointed out that the recent absence of arc volcanism in southwest Japan has resulted in the homogeneous crustal strength and uniform strain rate of the fault-bounded sliver.

Among the geographically defined Kinki district, we take notice of the tectonic domain surrounded by the MTL, NKTZ and ESTL. It is a damage zone accompanied by countless faults and enormous intra-arc basins, which are delineated by low gravity anomalies (see Figure 1). The mechanism of paradoxical basin formation at a contraction step of the MTL is discussed in this book (Itoh, Y., Kusumoto, S. and Takemura, K.). After the incipient subsidence stage in the Pliocene, an accelerated strain rate during the Quaternary provoked rapid sedimentation. A geophysical view of the architecture of the crust and the general trend of subordinate structures within this domain are discussed in the next section.

The Chubu domain is bordered by the ISTL and ESTL, and subdivided by the NKTZ into northern and southern sectors. The northern Chubu sector seems to be under the influence of the backarc inversion zone of northeast Japan, and all the active faults show dominant reverse slip. In contrast, the southern sector is characterized by numerous conjugate faults suggestive of an E-W regional compression. Although large-scale intra-arc basins do not develop in this area, Itoh et al. [37] demonstrated that conspicuous small basins are formed around termina‐ tions and stepping parts of the strike-slip faults.
