Slip Modes Along a Structurally-Driven Earthquake Barrier in Chile

IF 3.9 2区地球科学 Q1 GEOCHEMISTRY & GEOPHYSICS

Journal of Geophysical Research: Solid Earth Pub Date : 2025-06-20 DOI:10.1029/2024JB030796

Diego Molina-Ormazabal, Mathilde Radiguet, Jannes Münchmeyer, Nicolas Hernandez-Soto, Adrien Vezinet, Lea Pousse-Beltran, Catalina Castro, Marie-Pierre Doin, Juan Carlos Baez, Marcos Moreno, Andres Tassara, Philippe Durand, Anne Socquet

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引用次数: 0

Abstract

Oceanic ridges often collocate with seismic barriers and episodic aseismic slip. However, how subducted seafloor topography drives interactions between slow and fast slip remains unclear. Here, using GNSS, InSAR and seismicity, we show interactions between a deep slow slip event (SSE) and a nearby shallow earthquake sequence that occurred in 2020 in northern Chile. These events overlap with the subducted Copiapo ridge, which has served as a barrier for historical earthquake ruptures. Gravity field data and seismic tomography reveal that the SSE nucleated in a region hosting a subducted seamount. Six months later, the seismic sequence dynamically triggered the acceleration and migration of the deep SSE, while afterslip and aftershocks propagated up to another subducted seamount at shallower depth. Our findings suggest that subducted seamounts influence fault hydromechanics, where high pore-pressure and rate strengthening material promote continuous slip release, reducing slip deficit. This process is modulated by SSEs and low magnitude seismic sequences.

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智利结构驱动的地震屏障滑动模式

洋脊常与地震屏障和周期性地震滑动同时存在。然而，俯冲的海底地形如何驱动慢滑和快滑之间的相互作用仍不清楚。在这里，我们使用GNSS、InSAR和地震活动，展示了2020年发生在智利北部的深慢滑事件（SSE）和附近浅层地震序列之间的相互作用。这些事件与俯冲的Copiapo山脊重叠，这是历史上地震破裂的屏障。重力场数据和地震层析成像显示，东南地震成核位于俯冲海山所在区域。6个月后，地震序列动态触发了深SSE的加速和迁移，而余震和余震向上传播到另一个较浅深度的俯冲海山。研究结果表明，俯冲海山影响断层流体力学，高孔隙压力和速率强化物质促进滑动持续释放，减少滑动亏缺。这一过程受到sse和低震级地震序列的调节。

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来源期刊

Journal of Geophysical Research: Solid Earth Earth and Planetary Sciences-Geophysics

CiteScore

7.50

自引率

15.40%

发文量

559

期刊介绍： The Journal of Geophysical Research: Solid Earth serves as the premier publication for the breadth of solid Earth geophysics including (in alphabetical order): electromagnetic methods; exploration geophysics; geodesy and gravity; geodynamics, rheology, and plate kinematics; geomagnetism and paleomagnetism; hydrogeophysics; Instruments, techniques, and models; solid Earth interactions with the cryosphere, atmosphere, oceans, and climate; marine geology and geophysics; natural and anthropogenic hazards; near surface geophysics; petrology, geochemistry, and mineralogy; planet Earth physics and chemistry; rock mechanics and deformation; seismology; tectonophysics; and volcanology. JGR: Solid Earth has long distinguished itself as the venue for publication of Research Articles backed solidly by data and as well as presenting theoretical and numerical developments with broad applications. Research Articles published in JGR: Solid Earth have had long-term impacts in their fields. JGR: Solid Earth provides a venue for special issues and special themes based on conferences, workshops, and community initiatives. JGR: Solid Earth also publishes Commentaries on research and emerging trends in the field; these are commissioned by the editors, and suggestion are welcome.