巧家-东川地震空区浅层水库触发地震活动与深层构造闭锁的并置

中文摘要 AI 辅助

识别成熟地震空区的临界状态具有挑战性，特别是当水库蓄水等人为应力扰动叠加在构造载荷上时。利用巧家-东川地震空区（世界第二大水电站所在地）的高分辨率密集台阵目录，揭示了一种明显的垂直解耦机制。浅层活动表现出高b值（1.0），表明是流体驱动的水库触发地震活动。相反，深部地震活动（20公里）勾勒出一个以低b值（小于0.8）和高库仑应力积累率为特征的“闭锁asperity”。进一步识别出一个复杂的倾斜结构，表明存在复合断层运动学。此外，计算出的应力积累表明该地震空区处于具有较高破裂潜力的临界状态。研究结果表明，浅层诱发地震活动可以掩盖深部构造应变的无声积累。这种解耦模型为全球评估水库-断层系统中的地震风险提供了一个新框架。

英文摘要

Identifying the critical state of mature seismic gaps is challenging, especially when anthropogenic stress perturbations, such as reservoir impoundment, superimpose on tectonic loading. Here, utilizing a high-resolution dense array catalog from the Qiaojia-Dongchuan seismic gap (hosting the second-largest hydropower station in the world), we reveal a distinct vertical decoupling mechanism. The shallow activities exhibit high b-values (1.0), indicative of fluid-driven reservoir-triggered seismicity. Conversely, deep seismicity (20 km) outlines a 'locked asperity' characterized by low b-values (less than 0.8) and high Coulomb stress accumulation rate. We further identify a complex dipping structure, suggesting compound fault kinematics. Additionally, the calculated stress accumulation suggests this seismic gap is in a critical state with elevated rupture potential. Our findings indicate that shallow induced seismicity can mask the silent accumulation of deep tectonic strain. This decoupling model provides a new framework for assessing seismic risks in reservoir-fault systems globally.

发表机构

• University of Chinese Academy of Sciences（中国科学院大学）
• Harvard University（哈佛大学）

机构由 AI 辅助整理，请以论文原文为准。