本日選文（共 2 篇）。

[907] 利用新建立的 N-net 海底地震儀網於南海溝日向灘檢測淺部構造性顫動

Detection of Shallow Tectonic Tremors in Hyuga‐nada, Nankai Trough, Using the Newly Established N‐Net OBS Network

  • 期刊：JGR: Solid Earth (AGU/Wiley) — eTOC
  • Published：Tue, 17 Mar 2026 02:06:18 -0700
  • DOI：10.1029/2025GL121198
  • 原文連結：連結

Summary (EN) Using machine-learning on newly deployed offshore N‑net OBS data, the authors detected shallow tectonic tremors in Hyuga‑nada between July 2024 and September 2025. Two major tremor episodes occurred: one immediately after the August 2024 M7.0 earthquake and another three days before the January 2025 M6.7 event, with several tremors migrating alongside seismicity—suggesting slow‑slip transients promoted stress transfer along the plate boundary. Tremors clustered in fluid‑rich plate‑boundary zones and were absent in drained areas, indicating structural heterogeneity controls shallow slow‑earthquake dynamics and providing new insights into slow‑earthquake mechanics.

重點摘要（繁中） 作者將機器學習流程應用於新建立的N‑net海底OBS資料，於2024年7月至2025年9月間偵測到日向灘的淺層構造顫動。兩次主要顫動事件分別在2024年8月7.0級地震之後立即發生，以及在2025年1月6.7級地震前三天發生，且多起顫動與地震同時遷移，顯示慢滑移瞬態促進了板塊邊界上的應力轉移。顫動集中在富流體的板界帶並在排水區域不活躍，表明結構異質性調控了日向灘的淺層慢地震動力學，並提供對慢地震機制的新見解。

[892] 降雨誘發淺層滑坡之機制受地下水文構造調控：日本阿武隈山地北部花崗岩與花崗閃長岩區之案例

Mechanisms of rainfall-induced shallow landslides regulated by hydrological subsurface structures: Cases in granite and granodiorite areas in Northern Abukuma Mountains, Japan

  • 期刊：Earth-Science Reviews (ScienceDirect)
  • DOI：10.1016/j.enggeo.2026.108692
  • 原文連結：連結

Summary (EN) This study used field observations and slope models at granite and granodiorite hillslopes in the northern Abukuma Mountains (site of many 2019 typhoon landslides) to link subsurface regolith architecture and hydrological processes to rainfall-induced shallow landsliding. In granite slopes, an impervious bedrock beneath highly permeable soil promotes lateral throughflow and a basal saturated zone that thickens downslope and can reach the surface during intense short rainfall, producing shallow slides and head-hollow gullies. In granodiorite slopes, a thick soil mantle and more permeable bedrock with high water retention slows the wetting front at a transition between loose upper and stiffer lower soils; during prolonged, large-amount rainfall a perched groundwater table forms above a less-permeable lower layer and can induce translational shear failure, implying different rainfall thresholds (short intense vs. prolonged large-amount) for the two lithologies.

重點摘要（繁中） 本研究在北阿武隈山地的花崗岩與花崗閃長岩坡面，結合現地調查與坡面模型（模擬極端降雨期間孔隙水壓），探討不同地表覆蓋與物性結構如何控制降雨引發的淺層崩塌。花崗岩坡面下伏不透水基岩，上覆高滲透土層，促成底部飽和帶並以側向透流維持，飽和帶下膨且向下游增厚，在強烈短時降雨下可能達到地表，導致淺層滑動與集水窪頭部沖刷。花崗閃長岩坡面則具有厚土層與較高蓄水性的基岩，濕潤前緩速通過上部鬆散與下部堅實土層交界；在長時大量降雨下，較低滲透性的下層上方會形成懸置地下水位並可能沿平移破面誘發滑動，表示兩種岩性有不同的降雨閾值（花崗岩為短時強降雨，花崗閃長岩為長時大量降雨）。