REANALYSIS OF BEDROCK GROUND TEMPERATURE CHANGES PRIOR TO 2013 LUSHAN MS7.0 EARTHQUAKE |
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| Authors: | ZENG Di CHEN Li-chun CHEN Shun-yun LI Dong-yu |
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| Institution: | 1.Institute of Geology, China Earthquake Administration, Beijing 100029, China;2.State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China |
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| Abstract: | Before 2013 Lushan MS7.0 earthquake, the bedrock ground temperature in Kangding station, the cross-fault deformation and the borehole strain in Guza station all show that regional stress changes possibly occurred along the Xianshuihe Fault. In this paper, further analysis is made on the observation data of bedrock ground temperature in the three stations in the Xianshuihe fault zone, and the results are compared with borehole strain, seismometry and cross-fault deformation data. Stress temperature in the three stations dropped suddenly synchronously a few days before the Lushan earthquake, indicating the enhanced tension characteristics of the regional stress in the Qianning-Kangding zone. High-frequency components of bedrock temperature in the three stations also showed synchronous changes in the 80 days before the Lushan earthquake, with an estimated stress change range of 0.98~1.96MPa, an average of about 1.47MPa, which is close to the seismometry results. Besides, tensional mutation in borehole strain is consistent with the enhanced tensional characteristics of regional stress revealed by bedrock ground temperature. Comparison with cross-fault deformation shows that the stress change was different in different active segments of the Xianshuihe Fault in different time periods before the Lushan earthquake, but the regional stress change did appear along the Xianshuihe fault zone before the Lushan earthquake. |
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| Keywords: | bedrock ground temperature high-frequency components Lushan earthquake crustal stress |
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