In the southeast part of the Kii Peninsula, the Omine granitic body and the Kumano acidic body intrude into the Shimanto Belt and the Kumano Group of the Neogene Series. In particular, the Omine granitic body is thought to cause thermal metamorphism of the surrounding mudstone. The degree of thermal metamorphism of the mudstone can be estimated from the illite crystallinity （IC value）, which is calculated by the half-height width or full width at half maximum of the X-ray diffraction line of illite. In this study, the relationship between thermal metamorphism and physical properties of mudstones in the southern part of the Kii Peninsula was quantitatively evaluated by measured IC value, rebound hardness and true density. The spatial distribution of the IC values was used to discuss the characteristics of the distribution of landslide sites. The results showed that the rebound hardness increased as the IC value decreased. As for the relationship between IC value and true density, the true density increased with the increase of IC value. From the spatial distribution of IC values, the distribution patterns of thermal metamorphism could be classified into three categories. From the spatial distribution of IC values, the distribution patterns of thermal metamorphism could be classified into three categories. The area with the highest thermal metamorphism is influenced by the Omine granite. The most thermally metamorphosed area is considered to be influenced by the Omine granitic body, and it suggests that the granitic body is underlying the surface. A comparison between the high and low thermal metamorphism areas of the Hidakagawa Group in the Shimanto Belt shows that the high thermal metamorphism area tends to have fewer landslides.

Interferometric SAR analysis is an effective method for clarifying the annual surface displacement tendency. In this study, we used persistent scatterer SAR interferometry to detect surface displacements in the areas around Arima-Takatsuki Tectonic Line, which is the fault group near the epicenter of the 2018 northern Osaka earthquake, and near the Mt. Rokko active segment. As results of our analyses, we found that （i） the subsidence occurred near the Mt. Rokko active segment, （ii） the surface displacements in the wedge-shaped area located between the Arima-Takatsuki Tectonic Line and the Mt. Rokko active segment, and in the vicinity of the Minoh GNSS station were suggested to be changed in the uplift direction after the earthquake, and were possibly caused by changes in the groundwater level, （iii） the groundwater level changes may have caused surface displacement considered to be uplift in the wide area between the Ikoma Fault Zone and Uemachi Fault Zone, and （iv） the slip of the source fault may have caused westward surface displacement around the epicenter of the 2018 northern Osaka earthquake. Furthermore, we validated the estimated surface displacements by comparison with GNSS measurements and previous studies. In order to elucidate surface displacement mechanism around the faults, it is necessary to continue to analyze surface displacements using the analysis of SAR interferometry time series in the same area.