An earthquake with a moment magnitude of 7.5 (Mw) struck the northern Noto Peninsula, Ishikawa Prefecture, Japan, at 16:10 local time on January 1, 2024. This earthquake triggered a tsunami that propagated along the coastline of Ishikawa, Toyama, and Niigata Prefectures facing the Sea of Japan and significantly damaged coastal communities and infrastructure. Approximately 70 researchers from 23 universities or other institutes throughout Japan formed a joint research group to conduct a post-tsunami survey along a 340 km stretch of the coast. Based on the watermarks and traces of the tsunami, the inundation and run-up heights were surveyed using total stations, automatic optical levels, laser range finders, and a real-time kinematic (RTK) Global Navigation Satellite System (GNSS). The tidal correction was adjusted using astronomical tidal tables. In total, 303 survey records have been compiled, generating the NP2024TS (Noto Peninsula 2024 Tsunami Survey) dataset. This dataset provides comprehensive information on the inundation and run-up heights of the tsunami, which is useful for understanding tsunami characteristics and validating numerical tsunami models.

Long-term variation in the morphological characteristics of rivers is complicated as a result of temporally and spatially variable natural processes and anthropogenic disturbances. Better understanding of their relationship is therefore important for river basin management. The present study conducted a detailed analysis of a long-term dataset consisting of a 58-year topographic survey and related data on human impact to clarify the long-term variation in the morphological characteristics of the lower Tedori River in Japan. An empirical model was established through the assessment of spatiotemporal variations in nonlinear rates of adjustment. The results indicated that sediment extraction and dam construction profoundly affected the morphological characteristics of the lower Tedori River and that the vertical adjustment of the river channel experienced five phases. Degradation occurred from 7 to 16 km upstream from the river mouth over all phases. Two aggradation phases following two degradation phases were observed from the river mouth to 2 km upstream. Aggradation and degradation phases appeared alternately from 2 to 7 km. The representative nonlinear rates of vertical adjustment in the second phase were the highest compared with those in the other phases in the entire reach. The correlation analysis revealed that the incision phase was mostly coupled with channel narrowing, while widening followed the deposition phase. It was deduced from aerial photo analysis and a comparison between slope and empirical critical slope that the pattern in the lower Tedori River was braided during the period 1950–2000.

This study discusses the coastal sediment budget for the Ishikawa coast using 12 years of observational datasets; it involves an understanding the local and regional sediment dynamics, the intensity of the transport processes in the region, and sediment supply from a local river. Although alongshore sediment transport and sediment budgets have been analyzed in previous studies, only a few conducted cross-shore sediment transport evaluations. The concentration of suspended sediments will be determined in this study, taking into account the influence of waves that are associated with the coastal current. The cross-shore sediment transport using sediment budget analysis indicated that the net alongshore sediment transport directions in the surf and offshore zones are opposite on the Ishikawa coast. The increase in the sediment budget of the surf zone can be attributed to the river sediment supply and longshore sediment transport inflow. Because of the significant outflow components of longshore and cross-shore sediment transports, the offshore zone budget showed a decreasing trend. A detailed sensitivity study was performed by varying the input parameters, in order to determine the possible ranges of net transport rates and sediment transport to the adjacent coasts. The results demonstrated the possibility of a clockwise residual sediment circulation. Our method can be used to analyze the alongshore sediment transport for other coasts and supplement future studies on coastal sedimentology and sediment budgets.