Dual-initiation ruptures in the 2024 Noto earthquake encircling a fault asperity at a swarm edge

• 成果类型: Article
• 署名作者: Xu, Liuwei; Ji, Chen; Meng, Lingsen; Ampuero, Jean-Paul; Yunjun, Zhang; Mohanna, Saeed; Aoki, Yosuke
• 署名单位: University of California System; University of California Los Angeles; University of California System; University of California Santa Barbara; Institut de Recherche pour le Developpement (IRD); Universite Cote d'Azur; Observatoire de la Cote d'Azur; Centre National de la Recherche Scientifique (CNRS); Chinese Academy of Sciences; Aerospace Information Research Institute, CAS; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; University of Tokyo
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11806
• DOI: 10.1126/science.adp0493
• 发表日期: 2024-08-23
• 页码: 871-876
• 关键词: strong-motion; inversion; displacements; deformation; california; mechanism; physics; JAPAN; hanto; SEA

摘要

To reveal the connections between the 2024 moment magnitude (M (w)) 7.5 Noto earthquake in Japan and the seismicity swarms that preceded it, we investigated its rupture process through near-source waveform analysis and source imaging techniques, combining seismic and geodetic datasets. We found notable complexity in the initial rupture stages. A strong fault asperity, which remained unbroken in preceding seismic swarms, slowed down the rupture. Then, a second rupture initiated at the opposite edge of the asperity, and the asperity succumbed to double-pincer rupture fronts. The failure of this high-stress drop asperity drove the earthquake into a large-scale event. Our observations help unravel the crucial role of fault asperities in controlling swarm migration and rupture propagation and underscore the need for detailed seismological and interdisciplinary studies to assess seismic risk in swarm-prone regions.