Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

TECTONIC SETTING During the Cretaceous period, the Izanagi plate initiated flat- lying subduction, leading to slab rollback, and resulting in crustal- scale extension, along with the development of sinistral strike-slip fault systems extending from eastern and northeastern China to the Korean Peninsula (Kimet al., 2012; Kimet al., 2016). The YF, one of the large sinistral strike-slip faults, is bounded between Precambrian crystalline rocks and Cretaceous basin-fill sedimentary rocks. The neotectonic activities in the Korean Peninsula are mainly influenced by the initiation and propagation of the India-Eurasia collision, and the subduction of the Pacific and Philippine plates beneath the Eurasian plate (Cox and Engerbretson, 1985; Tapponier et al., 1986; Fig. 2a). Geodesy, paleo-stress analysis, focal mechanism, and borehole in-situ stress analysis indicated that the currently Korean Peninsula is under the ENE-WSWmaximumhorizontal compression (Jin and Park, 2006; Chang et al., 2010; Son et al., 2015; Kim et al., 2016; Kim et al., 2023). Under this stress field, the NE-SW trending strike-slip faults are more suitable for right-laterally inversion, supported by structural analysis (Won and Lee, 2018). Recent paleoseismological studies also reveal inversion of Gongju-Geumwang fault systems during Quaternary (Kim et al., 2022; Lee et al., 2023). Fig. 3: (a) LiDAR DEM map around the Mangye-ri exhibiting geomorphic features along with 1st grade lineament and the location of ERT profiles and trench. (b) Drone image of the inset of figure 2a. (c) Each of the ERT profiles showing similarity of anomalies. Relatively low-resistivity zones between high-resistivitiy layers represent fault zones in alignment with kinck point