ASSESSMENT OF TSUNAMI IMPACT ON THE COASTAL AREAS OF NIIGATA PREFECTURE FROM THE 2024 NOTO PENINSULA EARTHQUAKE

Abstract

 In January 2024, a tsunami trace survey and numerical propagation experiments were conducted to assess the impact of the tsunami originating from the Noto Peninsula on the coastal areas of Niigata Prefecture. During the survey, run-up heights were measured using RTK-GNSS along the coast from Itoigawa to Niigata East Port. Additionally, unmanned aerial vehicles were utilized to acquire planar topographic information. The numerical experiments were executed using fault parameters from the Geospatial Information Authority of Japan, encompassing the region from the Noto Peninsula to Akita Prefecture with a grid interval of 500 m. The results were compared to the tsunami arrival times at various locations. Further calculations were conducted using topographic data with a 10 m grid interval around Naoetsu Port, which were calibrated to match the observed values within the port. This facilitated the understanding of wave heights reaching the region. The field survey revealed a run-up height of 6 meters at the mouth of the Sekikawa River on the left bank. No significant tsunami traces were found west of Nou or east of Ogata. According to the numerical experiments, the tsunami reached Itoigawa in approximately 8 minutes due to the influence of water depth. Furthermore, the wave height upon reaching the Joetsu urban area was estimated to be around 2 m.