2026-02-27 ワシントン大学（UW）
In this map modeling subduction zone locking, red indicates where the plates are tightly locked and orange/yellow show less locking. Study sites are marked with red squares and the blue lines along the coast depict other faults — proposed fluid conduits in this study. The cross section shows fluid migration in more detail. Photo: Science Advances/Kidiwela et al.
＜関連情報＞
- https://www.washington.edu/news/2026/02/27/stress-testing-the-cascadia-subduction-zone-reveals-variability-that-could-impact-how-earthquakes-spread/
- https://www.science.org/doi/10.1126/sciadv.aea3684
活発な原始断層と流体ハイウェイ：地震ノイズがカスケーディアにおける隠れた沈み込みのダイナミクスを明らかにする Active protothrusts and fluid highways: Seismic noise reveals hidden subduction dynamics in Cascadia
Maleen Kidiwela, Marine A. Denolle, William S. D. Wilcock, and Kuan-Fu Feng
Science Advances Published:27 Feb 2026
Abstract
Complex interactions between strain accumulation, fault slip, and fluid migration influence shallow subduction zone dynamics. Using a decade of continuous ambient seismic data from Cascadia’s seafloor observatories, we identified distinct regional variations in subduction dynamics. Northern Cascadia exhibits a fully locked megathrust with persistent strain accumulation, while central Cascadia displays a slow slip event on protothrusts and rapid fluid migration along fault systems in the overriding plate. Effective fluid transport through the décollement and the Alvin Canyon Fault likely modulates the earthquake behavior but does not cause slow slip events on the megathrust and likely stabilizes large earthquakes, promoting rupture arrest.
