[O-09] Mechanism of the 2024 Noto Peninsula Earthquake and its disaster

[O09-03] Coseismic landslides in the 2024 Noto Peninsula Earthquake

★Invited Papers

*Yuki Matsushi¹ (1.Disaster Prevention Research Institute, Kyoto University)

Keywords:Noto Peninsula earthquake, coseismic landslides, landslide damming, topographic amplification, bedrock weathering zone

This presentation overviews preliminary results of multifaceted analyses of the coseismic landslides (including rockfall, slope failure, reactivated landslides, and debris flow) caused by the Noto Peninsula earthquake on January 1, 2024. Numerous landslides occurred in steep mountainous terrains, which yield vast volume of sediment from hillslopes into fluvial channels. Some of those dammed the channel by the landslide debris to form natural barrier lakes. Inventory mapping revealed the localized distribution of the landslides, regulated most probably by geologic and topographic conditions. Areal density, individual sizes and types of the landslides can be explained by coupled factors of lithological fragility of the hillslopes to the seismic shaking and amplification of ground motion at the hilltops. Landslide susceptibility in a local scale seems to be linked with characteristic weathering processes of the sedimentary (mainly mud-to-siltstone) and volcanic (mainly pyroclastic) rocks and the resultant structure, thickness, and physicochemical properties of the bedrock weathering zone.