1:45 PM - 3:15 PM
[O11-P12] Why the Noto Peninsula Earthquake caused liquefaction in Niigata City? Examining what characteristics of the sand.
Keywords:Soil Liquefaction, Earthquake, Particle size analysis
Sand ground appeared to liquefy in Niigata Prefecture due to the 1 January 2024 Noto Peninsula Earthquake. It was strange that liquefaction damage occurred in that area about 160 km away from the epicenter, even though other areas more closer to the epicenter suffered only some liquefaction damage with the same seismic intensity of 5+.
This study aims to reveal overall structure of liquefied layer with the laser diffraction particle size analyzer. Yet, the problem is whether the results are related to the topography of the area.
First, to reproduce liquefaction and count the number of vibrations required to it, sand from the liquefaction occurrence site and other areas were placed in a plastic cup, and the results were compared (Figure 1). Each sand was measured with a grain size analyzer and the results were compared (Figure 2). Next, with the particle size analyzer, examining to a depth of 2cm increase at a time soil samples were taken from the sand layers, which find conditions that make liquefaction extremely likely to occur (Figure 3, Figure 4). Furthermore, a review of new and old maps of the area revealed a topography consistent with the granularity analysis results (Figure 5, Figure 6).
Specifically, the areas had a history of river reclamation or reclamation by beach sand. These results link to identify conditions that make liquefaction likely to occur.
References
Atsushi U. et al. (2024). [ Liquefaction damage investigation report for Niigata City area due to the 2024 Noto Peninsula earthquake] 2024 nen Notohantojishin niyoru Niigatasi shuhen no ekijyoukahigai chousa houkokusyo (in Japanese). 2024, 39p
Shinanogawa-Karyu Work Office. Survey map of the Shinano River in 1901: Sekiya to Sonoki. Available at https://www.hrr.mlit.go.jp/shinage/shinanogawa/meiji/index_2.html, Accessed 12 April. 2025.
Geological Survey of Japan. Geological map 1:50,000 7. Niigata. Available at https://www.gsj.jp/Map/JP/geology4-7.html#07009, Accessed 12 April. 2025.
This study aims to reveal overall structure of liquefied layer with the laser diffraction particle size analyzer. Yet, the problem is whether the results are related to the topography of the area.
First, to reproduce liquefaction and count the number of vibrations required to it, sand from the liquefaction occurrence site and other areas were placed in a plastic cup, and the results were compared (Figure 1). Each sand was measured with a grain size analyzer and the results were compared (Figure 2). Next, with the particle size analyzer, examining to a depth of 2cm increase at a time soil samples were taken from the sand layers, which find conditions that make liquefaction extremely likely to occur (Figure 3, Figure 4). Furthermore, a review of new and old maps of the area revealed a topography consistent with the granularity analysis results (Figure 5, Figure 6).
Specifically, the areas had a history of river reclamation or reclamation by beach sand. These results link to identify conditions that make liquefaction likely to occur.
References
Atsushi U. et al. (2024). [ Liquefaction damage investigation report for Niigata City area due to the 2024 Noto Peninsula earthquake] 2024 nen Notohantojishin niyoru Niigatasi shuhen no ekijyoukahigai chousa houkokusyo (in Japanese). 2024, 39p
Shinanogawa-Karyu Work Office. Survey map of the Shinano River in 1901: Sekiya to Sonoki. Available at https://www.hrr.mlit.go.jp/shinage/shinanogawa/meiji/index_2.html, Accessed 12 April. 2025.
Geological Survey of Japan. Geological map 1:50,000 7. Niigata. Available at https://www.gsj.jp/Map/JP/geology4-7.html#07009, Accessed 12 April. 2025.