对2022年9月5日四川泸定MS 6.8地震前加卸载响应比（LURR）异常时空演化特征和震前预测过程进行回顾。年尺度的LURR计算结果可以识别高应力背景区，为年度危险区的判断提供依据；周月尺度的计算结果可以反映地震发生前的孕震区介质由稳定阶段进入损伤阶段的转变。泸定地震前，LURR中短期异常空间分布呈现“沿鲜水河断裂方向展布—向震源区集中—异常幅度增加、区域扩展—震后减弱并消失”的演化过程；LURR时序曲线在震前出现明显的高值变化，在高值回落的过程中发震，震后LURR时序曲线回落至阈值线1.0附近。综上，LURR异常在空间上具有逐步向震中集中的趋势，时间上具有明显的阶段性特征，将LURR方法在长中短期一体化预测中进行应用，可以为今后对该区域地震趋势研判提供较好的依据。
In this paper, the temporal and spatial evolution characteristics of load-unload response ratio (LURR) anomalies and the prediction process before the Luding MS 6.8 earthquake on September 5, 2022 are reviewed. The LURR calculation results on the annual scale can be used to identify the high-stress background area and provide a basis for the judgment of the annual risk region. The calculation results on the weekly and monthly scale can reflect the transition of the medium in the seismogenic region from the stable stage to the damaged stage before the earthquake. The spatial distribution of LURR before the earthquake shows an evolutionary process of "distribution along Xianshuihe Fault direction-concentrating to the focal area-increasing of abnormal amplitude and regional expansion-weakening and disappearing after the earthquake". The LURR time series curve shows an obvious change of high value before the earthquake, and the earthquake occursin the process of falling high value. After the Luding earthquake, the LURR times series curve fallsback to the threshold line (1.0). In conclusion, LURR anomaly tends to gradually concentrate toward the epicenter in space and has obvious stage characteristics in time. The application of the LURR method in the prediction of long-medium-short term integration can provide a better basis for the judgment of future earthquake trend in this region.
2022,43（6）: 125-130 收稿日期：2022-09-14
DOI：10.3969/j.issn.1003-3246.2022.06.017
基金项目：国家重点研发计划（项目编号：2018YFE0109700）；国家自然科学基金联合基金（项目编号：U2039205）；中国地震台网中心青年基金（项目编号：122302138）
作者简介：于晨(1988-),男,工程师,主要从事地震电磁学研究。E-mail:yuchen@seis.ac.cn
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