The 1 January 2024 Noto Peninsula co-seismic landslides hazards: Preliminary results

Abstract

On the first day of 2024, a strong Mw.7.6 earthquake followed by a tsunami shook the Noto Peninsula (Japan) located on the coast facing the Sea of Japan. It resulted in numerous casualties, infrastructures and dwelling destroyed. The earthquake also triggered an estimated 5,000 coastal and mountain co-seismic mass-movements, from which 930 were identified by aerial photographs and digitized from the emergency aerial photographs (2/1/2024). The goal has been to provide a preliminary assessment of their distribution and characteristics. The medium surface of the landslides was found to be 1,749 m2, with numerous small < 50 m2 landslides and at least one large deep-seated landslide (0.8 km × 1 km). The mountain landslides were concentrated around two clusters, which were not close to the epicentre, but around 7 km and 10 km from the epicentre. From a disaster-risk perspective, the 1/1/2024 Noto Peninsula earthquake is typical of a ‘coastal earthquake’ where the coastal landslides, even sparse collapsed on the main artery of the peninsula, the ring road, isolating communities and hampering the disaster relief process.