Sediment-related disasters induced by the Noto Peninsula Earthquake in January 2024

On January 1, 2024, a large-scale earthquake with a magnitude of 7.6 struck the Noto region, Ishikawa Prefecture, Japan. The earthquake and resulting tsunami together with crustal movement caused extensive damage across the region. The 420 cases of sediment movement (389 in Ishikawa Prefecture, 18 in Niigata Prefecture, and 13 in Toyama Prefecture) resulted in numerous casualties as well as damage to homes (57 completely destroyed, 33 partially destroyed, and 17 partially damaged) and infrastructure. River blockages occurred at 14 locations in six rivers. The Japan Society of Erosion Control Engineering immediately established a committee to investigate the sediment-related disasters, dispatching an urgent investigation team to the disaster area in collaboration with the Japan Landslide Society. On February 11 and 12, 2024, the team visited eight locations on the Noto Peninsula, investigating four landslide sites and four landslide with river blockage sites. Large-scale landslides along the coast on the northern side of the peninsula and a concentrated area of shallow landslides with associated continuous river blockages in the inland area were documented. The team concluded that the risk of the landslide dam body could burst and cause a debris flow at many river blockages is low. However, future disaster planning should include countermeasures aimed at the elimination of multiple large-scale river blockages formed in succession upstream and downstream.