Tsunetaka Haruka, Murakami Wataru, Daimaru Hiromu
Forestry and Forest Products Research Institute, Tsukuba, 305-8687, Japan.
Ishikawa Prefectural University, Nonoichi, 921-8836, Japan.
Sci Rep. 2024 Nov 14;14(1):28026. doi: 10.1038/s41598-024-79044-4.
Large earthquakes can instantaneously reshape coastal landforms owing to fault zone ruptures that uplift the Earth's surface. On January 1, 2024, in the north of the Noto Peninsula, central Japan, an Mj7.6 (Mw7.5) earthquake occurred, triggering coastal uplift of up to 4 m. To measure the resulting shoreline advance, we analyzed orthophotos taken before and after the earthquake, focusing on two bays in the northwest of the Noto Peninsula where the largest uplift occurred. In response to the uplift, the shoreline advanced by up to 200 m, increasing the total area of the coastal plains by 0.46 km. The maximum shoreline extension occurred in the midsection of both bays, while the extension at the edges was less than 20 m, possibly reflecting the shoreface topography and bathymetry existing before the uplift. The uplift exposed previously undersea rocks, forming new coastal plains and extending river channels. Our results indicate that coastal landforms such as sandy beaches, coastal plains, shore platforms, and the sediment budgets of feeding drainage systems were substantially altered by this earthquake, and a long recovery period is anticipated. Our findings serve as a crucial benchmark for tracking future changes in shorelines in response to coastal landform adjustments.
由于断层带破裂使地表隆起，大地震能够瞬间重塑沿海地貌。2024年1月1日，日本中部能登半岛北部发生了里氏7.6级（矩震级7.5级）地震，引发了高达4米的沿海地区隆起。为了测量由此导致的海岸线推进情况，我们分析了地震前后拍摄的正射影像，重点关注能登半岛西北部两个隆起幅度最大的海湾。作为对隆起的响应，海岸线推进了多达200米，沿海平原总面积增加了0.46平方千米。最大的海岸线延伸发生在两个海湾的中部，而边缘处的延伸不到20米，这可能反映了隆起前存在的滨面地形和水深情况。隆起使先前的海底岩石露出水面，形成了新的沿海平原并延长了河道。我们的结果表明，诸如沙滩、沿海平原、海岸平台以及供水排水系统的沉积物收支等沿海地貌因这次地震而发生了显著改变，预计需要很长时间才能恢复。我们的研究结果为追踪未来海岸线因沿海地貌调整而发生的变化提供了关键基准。
