热测应力:测震学证据  

Evidence from seismological observation for detecting dynamic change in crustal stress by bedrock temperature

作　　者：陈顺云[1] 刘培洵[1] 陈立春[1,2] 刘琼颖 Shunyun Chen;Peixun Liu;Lichun Chen;Qiongying Liu(State Key Laboratory of Earthquake Dynamics.Institute of Geology,China Earthquake Administration,Beijing 100029,China;College of Earth Sciences,Guilin University of Technology,Guilin 541006,China)

机构地区：[1]中国地震局地质研究所地震动力学国家重点实验室,北京100029 [2]桂林理工大学地球科学学院,桂林541006

出　　处：《科学通报》2020年第22期2395-2405,共11页Chinese Science Bulletin

基　　金：国家重点研发计划(2018YFC1503304);中央级公益性科研院所基本科研业务费专项(IGCEA1605,IGCEA1815);国家自然科学基金(41474162)资助。

摘　　要：通过基岩温度观测可以获取地壳应力动态变化信息(称热测应力),但缺乏与其他观测手段的对比验证.本研究基于康定Ms6.3级地震同震温度响应,结合测震学结果,对同震应力变化的量级和空间分布特征等开展对比分析.结果显示:(1)热测应力与测震学两种方法获得的结果,应力变化的量级一致;从应力张压特性与温度变化上看,拉张降温,挤压升温,与理论和实验结果相吻合.(2)依据不同基岩温度测点获得的应力变化的张、压分区情况,康定地震的震源体深度更接近于测震学研究结果的上限范围.这意味着,基于基岩温度获取的地壳应力变化结果,可对震源分析提供一个新的约束条件.总之,随着基岩温度测量技术的提高,基岩温度观测有可能成为一种观测地壳应力动态变化的常规手段.Dynamic changes in crustal stress are of crucial importance in present-day crustal movements and earthquake dynamics,but they are very difficult to be determined. Recently, dynamic crustal stress is mainly obtained by measuring rock deformations due to crustal stress. In fact, stress change not only generates rock deformation, but also changes rock temperature. Under adiabatic condition, temperature variations are directly related to the volumetric strain variation.During loading, temperature is decreased in tension area while it is increased within compression area. Bedrock temperature is potentially modified by loading from surrounding rock bodies during tectonic activity process. Thus,bedrock temperature is a potential tool for observing dynamic changes in crustal stress. However, this needs to be verified by in situ experiments.On November 22 nd, 2014, an Ms6.3 earthquake hit Kangding County, Sichuan Province, southwestern China. The earthquake occurred on the segment of the Xianshuihe fault zone between Kangding and Daofu. About five years earlier, a bedrock temperature measurement network was installed near the epicentral location. Thus, this event made it possible to directly verify the accuracy of the method of determining crustal stress by in-situ measurements of bedrock temperature.Co-seismic temperature responses of Ms6.3 Kangding earthquake were detected and regarding temperature response to stress change, these co-seismic temperature changes represented co-seismic stress changes.Here, we have compared the co-seismic temperature responses of Kangding earthquake with co-seismic stress change which was achieved by seismology. First, the order of magnitude of the stress change was achieved by a simple point source model in seismology. Second, the spatial distribution characteristics of compression or tension state accompanying with Kangding earthquake were calculated according to seismic dislocation model. Besides, the effects of different Young moduli of surrounding rocks, length of seismic sliding surf

关 键 词：热测应力 基岩温度 地壳应力 康定地震 同震响应 

分 类 号：P315.6[天文地球—地震学]