2:00 PM - 2:15 PM
[HDS08-14] Landslides induced by the 2024 Noto Peninsula earthquake and their future: lessons from the 2004 Chuetsu earthquake
Keywords:2024 Noto Peninsula earthquake, Landslides, 2004 Chuetsu earthquake
We investigated the landslides induced by the M7.6 2024 Noto Peninsula earthquake by using aerial photographs, high resolution DEM, and rainfall data. The landslides were not directly controlled by seismic intensity, which means that landslides were not concentrated in the areas with highest intensity, 7 or 6+. Instead, the landslide distribution was controlled by bedrock geology. Landslides occurred most concentratedly in Neogene dacite to rhyolite pyroclastic rocks. The landslides had three typical types. One was shallow landslides of hollow-filling sediments that transformed into debris flows. They occurred in the pyroclastic rock area, which might be due to low permeabilities of the bedrock. Large landslides of siliceous siltstone occurred as reactivation of previous landslides that were undercut by erosion. One large rock avalanche with the length of 1 km occurred in Paleogene sedimentary rock area without clear preceding gravitational deformation.
The affected area had many landslide bodies, but most of them were not reactivated except for undercut ones; small cracks were made in some of the landslide bodies. The affected area had preceding rainfall as much as 400 mm in 30 days before the earthquake, which was similar to the rainfall amounts preceding the M6.9 2004 Chuetsu earthquake. The Chuetsu earthquake induced many landslides in the similar goelogical setting with that of the 2024 Noto Peninsula earthquake. It induced the fluidization of hollow-filling sediments and reactivation of undercut landslides. These similar features between the landslides by both the earthquake may be due to the preceding rainfalls. The Chuetsu earthquake was followed by heavy snow and then its melting in the spring, which however did not cause severe landslide disaster and many cracks made during the earthquake remained as they were. This may show the possible future of the affected area of the 2024 Noto Peninsula earthquake.
The affected area had many landslide bodies, but most of them were not reactivated except for undercut ones; small cracks were made in some of the landslide bodies. The affected area had preceding rainfall as much as 400 mm in 30 days before the earthquake, which was similar to the rainfall amounts preceding the M6.9 2004 Chuetsu earthquake. The Chuetsu earthquake induced many landslides in the similar goelogical setting with that of the 2024 Noto Peninsula earthquake. It induced the fluidization of hollow-filling sediments and reactivation of undercut landslides. These similar features between the landslides by both the earthquake may be due to the preceding rainfalls. The Chuetsu earthquake was followed by heavy snow and then its melting in the spring, which however did not cause severe landslide disaster and many cracks made during the earthquake remained as they were. This may show the possible future of the affected area of the 2024 Noto Peninsula earthquake.