近日，中国地震局张风雪团队研究了中国四川长宁水力压裂带速度结构及其成因：对长宁地震的影响。该项研究成果发表在2025年9月18日出版的《中国科学：地球科学》杂志上。

长宁地区位于四川盆地南部，历来被认为是构造稳定的地区。然而，近年来，随着大规模工业活动的扩大，地震活动显著增加。兴文5.7级和长宁6.0级地震在短时间内连续发生，引起了地震学界和公众的高度关注。

为了更好地了解地下活动与地下速度结构的关系及其对地震活动性的影响，研究组首先从密集的临时宽带地震台站中选取大量高质量的P、S波初到时间，然后在长宁水力压裂带浅层顶进行局部地震走时层析反演高分辨率P、S波速度模型。结果表明，速度非均质性一般与地层年龄有较好的相关性，而圈闭提取层附近的局部速度异常与注入压力变化有关。

此外，低纵波速度异常在兴文和长宁地震带之间形成了一条连续带，表明存在深部地下流体运移通道。虽然不能排除其他孕震机制，但这一发现优先支持了兴文地震激活的长距离通道流体运移有助于长宁地震发生的假设。

附：英文原文

Title: Velocity structure and its origin in the Changning hydraulic fracturing zone, Sichuan, China: Implications for the Changning earthquake

Author: Yu LI, Fengxue ZHANG, Jianping WU, Yiping CHEN

Issue&Volume: 2025/09/18

Abstract: The Changning region, located in the southern Sichuan Basin, has historically been regarded as tectonically stable. However, in recent years, seismicity has increased significantly alongside the expansion of large-scale industrial activities. The successive occurrences of the Xingwen MS5.7 and Changning MS6.0 earthquakes within a short interval have attracted considerable attention from both the seismological community and the public. To better understand the relationship between industrial activities and subsurface velocity structures, as well as their influence on seismicity, this study first selects a large number of high-quality P- and S-wave first arrival times from a dense array of temporary broadband seismic stations, and then conducts local earthquake traveltime tomography to invert for high-resolution P- and S-wave velocity models in the shallow crust beneath the Changning hydraulic fracturing zone. The results reveal that velocity heterogeneities are generally correlated well with stratigraphic age, while localized velocity anomalies near industrial extraction layers are associated with injection pressure variations. Moreover, a low P-wave velocity anomaly forms a continuous belt linking the Xingwen and Changning seismic zones, indicative of a deep subsurface fluid migration channel. Although alternative seismogenic mechanisms cannot be ruled out, this finding preferentially supports a hypothesis in which fluid migration along a long-distance channel activated by the Xingwen earthquake contributes to the initiation of the Changning earthquake.

DOI: 10.1007/s11430-024-1673-y

Source: https://www.sciengine.com/SCES/doi/10.1007/s11430-024-1673-y