浙江省珊溪水库2006年2月4日至11日发生8个ML 4以上地震,最大地震为ML 4.6地震,截至2009年12月10日,共发生1 063次小地震。为探讨8个ML 4以上地震主发震断层的库仑应力变化特征以及库仑应力变化对后续地震发生的促进作用,基于库仑破裂准则,计算珊溪水库该ML 4.6震群的静态库仑应力变化,讨论不同有效摩擦系数对库仑应力变化的影响,并依据Dieterich速率—状态摩擦定律计算并讨论其静态库伦应力变化对后续地震活动性的影响。结果表明,珊溪水库8次ML 4.0以上地震的静态库仑应力变化及库水下渗导致的静摩擦力变化,对后续地震的发生起到一定促进作用,约76.3%的地震发生在库仑应力变化为正的区域;有效摩擦系数的取值对库仑应力场与余震分布之间的关系影响不大;计算F11-1、F11-2及F11-3分支断层中部的库仑应力变化,发现库仑应力在F11-1、F11-2断裂上降低,在F11-3断裂上增加,表明未来地震在F11-3断裂附近多发的可能性更大。
From February 4th to 11th, 2006, there were 8 earthquakes of ML 4 or above at Shanxi reservoir in Zhejiang Province, with the largest earthquake being the ML 4.6 earthquake. As of December 10th, 2009, a total of 1 063 small earthquakes had occurred. In order to explore the Coulomb stress variation characteristics of the main fault of 8 ML 4 and above earthquakes, as well as the promoting effect of Coulomb stress variation on subsequent earthquakes, based on the Coulomb failure criterion, the static Coulomb stress variation of the ML 4.6 earthquake swarm in Shanxi reservoir was calculated, and the influence of different effective friction coefficients on Coulomb stress variation was discussed. And calculate and discuss the impact of static Coulomb stress changes on subsequent seismic activity based on Dietrich's rate state friction law. The results show that the static Coulomb stress changes and the static friction force changes caused by the infiltration of reservoir water in 8 ML 4.0 and above earthquakes in the Shanxi reservoir have played a certain promoting role in the occurrence of subsequent earthquakes. About 76.3% of earthquakes occur in areas with positive Coulomb stress changes; the effective friction coefficient has little effect on the relationship between the Coulomb stress field and aftershock distribution; calculation of the Coulomb stress changes in the middle of F11-1, F11-2, and F11-3 branch faults showed that Coulomb stress decreased on F11-1 and F11-2 faults, and increased on F11-3 faults, indicating a greater likelihood of future earthquakes occurring near F11-3 faults.
2023,44(5): 18-28 收稿日期:2022-05-12
DOI:10.3969/j.issn.1003-3246.2023.05.003
基金项目:浙江省地震局科技项目(项目编号:2020zjj03)
作者简介:袁文秀(1992-),女,硕士研究生,工程师,主要从事地震形变分析预报研究工作。E-mail:1127360835@qq.com
参考文献:
龚俊,汪贞杰,戴煜暄.联合测震和GPS资料反演双溪-焦溪垟断裂运动特征[J].测绘科学,2021,46(12):1-6.
刘方斌,曲均浩. 临潭-宕昌断裂及附近地区静态库仑应力变化及地震活动性研究[J]. 大地测量与地球动力学,2018,38(9):886-890.
马志江,钟羽云,韩用兵,等. 温州珊溪水库诱发地震构造条件[J]. 地球科学,2016,41(8):1 413-1 423.
杨福平,余刚群,侯林峰,等.大地电磁测深在珊溪水库诱发地震研究中的应用[J]. 工程地球物理学报,2019,16(2):203-210).
杨福平,赵理芳,余刚群,等. 珊溪水库地区三维构造特征与深部水库诱发地震环境研究[J]. 大地测量与地球动力学,2021,41(12):1 264-1 270.
万永革,吴忠良,周公威,等. 几次复杂地震中不同破裂事件之间的"应力触发"问题[J]. 地震学报,2000,22(6):568-576.
钟羽云,张帆,赵冬. 珊溪水库ML 4.6震群精确定位与发震构造研究[J]. 地震研究,2011,34(2):158-165.
钟羽云,朱新运,张震峰,等. 飞云江珊溪水库地震[M]. 杭州:浙江大学大学出版社,2017:1-29.
Dieterich J. A constitutive Law For rate of Earthquake Production and its Application to Earthquake Clustering[J]. Journal of Geophysical Research:Solid Earth, 1994, 99(B2):2 601-2 618.
Harris R A. Introduction to Special Section:Stress Triggers, Stress Shadows and Implications for Seismic Hazard[J]. J Geophys Res Solid Earth:Solid Earth, 1998, 103(B10):24 347-24 358.
Hainzl S, Enescu B, Cocco M, et al. Aftershock Modeling Based on Uncertain Stress Calculations[J]. Journal of Geophysical Research:Solid Earth, 2009, 114(B5):B05309.
Stein R S, King G C P, Lin J. Change in Failure Stress on the Southern San Andreas Fault System Caused by the 1992 Magnitude=7.4 Landers Earthquake[J]. Science, 1992, 258(5 086):1 328-1 332.
Stein R S, Barka A A, Dieterich J H. Progressive failure on the North Anatolian fault since 1939 by earthquake stress triggering[J]. Geophysical Journal International, 1997, 128(3):594-604.
Wells D L, Coppersmith K J. New Empirical Relationships among Magnitude, Rupture Length, Rupture Width, Rupture Area, and Surface Displacement[J]. Bulletin of the Seismological Society of America, 1994, 84(4):974-1 002.