则木河断裂带南段的GNSS形变监测及运动特征研究  

GNSS DEFORMATION MONITORING AND MOVEMENT CHARACTERISTICS OF SOUTHERN SECTION OF ZEMUHE FAULT ZONE

作　　者：黄子轩 乔学军[1] 余鹏飞[1] 赵斌[1] 陈正松[1] 师宏波 HUANG Zi-xuan;QIAO Xue-jun;YU Peng-fei;ZHAO Bin;CHEN Zheng-song;SHI Hong-bo(Institute of Seismology,China Earthquake Administration,Wuhan 430071,Hubei,China;China Earthquake Network Center,Beijing 100045,China)

机构地区：[1]中国地震局地震研究所,湖北武汉430071 [2]中国地震台网中心,北京100045

出　　处：《内陆地震》2025年第1期20-33,共14页Inland Earthquake

基　　金：国家自然科学基金重点项目(42130101);国家重点研发计划“重大自然灾害防控与公共安全”重点专项(2022YFC3003703);中国地震局地震研究所与应急管理部国家白然灾害防治研究院基本科研业务费专项(IS202226318);新疆地质灾害防治重点实验室开放基金(XKLGP2022K01,XKLGP2022K02).

摘　　要：则木河断裂带作为大凉山子块体和川滇菱形块体的共同边界,连接着活跃的青藏高原东南部和稳定的华南块体,该断裂带发生强震的风险正在增加。利用2017年以来在近场新建的连续GNSS观测资料及已发表的区域GNSS观测数据,对则木河断裂带南段的震间形变特征和应力分配状态进行了定量分析。在获取震间运动场的基础上,基于双断层位错模型反演了断层的运动学参数,结果表明,则木河断裂带南段的滑动速率为3.57±0.47 mm/a,大凉山断裂带南段的滑动速率为5.05±0.47 mm/a。新建的则木河断裂带的近场数据对于模型估计的精度具有重要影响,显著提升了双断层位错模型的分辨能力。应变率结果表明,川滇地块东边界主应变率方向呈现SW-NE向拉张和NW-SE向挤压的特征;则木河断裂带南段呈现出较高的应力状态,拉张应变率高于挤压应变率,平均量级分别为41 nstrain/a和27 nstrain/a,并处于最大剪切应变率高梯度带上,平均量级约(28~40)nstrain/a,具有较高的应力和能量积累。Zemuhe fault zone,serving as a common boundary between the Daliangshan sub-block and the Chuan-dian rhombohedral block,connects the active southeastern Tibetan Plateau with the stable Southern China block,and recent research indicates an increasing risk of strong earthquakes along this fault zone.The seismic deformation characteristics and stress distribution state of the southern section of the Zemuhe fault zone are quantitatively analyzed in this paper,utilizing newly established continuous GNSS observation data in the near field along with published regional GNSS observation data since 2017.By obtaining the interseismic motion field,we invert kinematic parameters of faults based on a double fault dislocation model.The results reveal that slip rates of the southern Zemuhe fault zone is 3.57±0.47 mm/yr and of the southern Daliangshan fault zone is 5.05±0.47 mm/yr.The near-field data of the newly constructed Zemuhe fault zone exerts a significant influence on the precision of model estimation,thereby substantially enhancing the resolution of the double-fault dislocation model.The strain rate results show that the principal strain rate direction of the eastern boundary of the Sichuan-Yunnan block is characterized by SW-NE stretching and NW-SE squeezing.The southern section of the Zemuhe fault zone presents a higher stress state,with the tensile strain rate being higher than the compressive strain rate,with the average magnitude of 41 nstrain/yr and 27 nstrain/yr,respectively,and is in the high gradient zone of the maximum shear strain rate,with the average magnitude of 28~40 nstrain/yr,indicating significant stress and energy accumulation.

关 键 词：则木河断裂带 GNSS形变监测 滑动速率 闭锁深度 地震危险性 

分 类 号：P315.7[天文地球—地震学]