[1]LIU Jie,JI Lingyun,SHI Fuqiang,et al.Characterization of the Observed Geophysical Anomalies Prior to Strong Earthquakes in Chinese Mainland[J].Journal of Seismological Research,2025,(02):300-311.[doi:10.20015/j.cnki.ISSN1000-0666.2025.0032
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Journal of Seismological Research[ISSN 1000-0666/CN 53-1062/P] Volume:
Number of periods:
2025 02
Page number:
300-311
Column:
Public date:
2025-02-10
- Title:
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Characterization of the Observed Geophysical Anomalies Prior to Strong Earthquakes in Chinese Mainland
- Author(s):
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LIU Jie1; 2; JI Lingyun3; SHI Fuqiang1; 2; HU Nan1; 2; QI Yuping4; WANG Guangming5; ZHANG Lifeng6; GUO Lei7; JIANG Jiajia8
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(1.Shaanxi Earthquake Agency,Xi'an 710068,Shaanxi,China)(2.Shaanxi Xi'an Deep Earth Structure Observation and Research Station of China EarthquakeAdministration,Xi'an 710068,Shaanxi,China)(3.The Second Monitoring and Application Center,China Earthquake Administration,Xi'an 710054,Shaanxi,China)(4.Sichuan Earthquake Agency,Chengdu 610041,Sichuan,China)(5.Yunnan Earthquake Agency,Kunming 650224,Yunnan,China)(6.Qinghai Earthquake Agency,Xining 810001,Qinghai,China)(7.Hebei Earthquake Agency,Shijiazhuang 050021,Hebei,China)(8.Gansu Earthquake Agency,Lanzhou 050021,Gansu,China)
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- Keywords:
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strong earthquakes in Chinese Mainland; geophysical field; temporal and spatial characteristics; evolutionary patterns
- CLC:
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P315.72
- DOI:
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10.20015/j.cnki.ISSN1000-0666.2025.0032
- Abstract:
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In order to find out the characteristics and patterns of the anomalies before strong earthquakes,we sort out 975 geophysical anomalies before 33 strong earthquakes(MS≥6.0)in Chinese Mainland from 1966 to 2017.Among these anomalies,there are 435 underground fluid anomalies,153 electromagnetic anomalies,282 deformation anomalies and 105 other anomalies.Underground fluid anomalies are mainly characterized by water radon,water level,and water temperature.Electromagnetic anomalies are mainly characterized by ground resistivity and geomagnetism.Deformation anomalies are mainly characterized by inclination,leveling,and volumetric strain.The analysis shows:①Anomalies evolved in distinct stages before the earthquakes.Trend-type anomalies were dominant in the middle and long term,and abrupt-variation anomalies were dominant in the short term.②The number and the feature of the anomalies in different regions differed.The fluid and deformation anomalies were dominant in the short-term stage in the northern and central parts of the North-South Seismic Belt.The Hydrogeological anomalies were dominant in the southern part of the North-South Belt.The fluid and electromagnetic anomalies were dominant in the inner part of the Qinghai-Tibetan Block.The number of these anomalies continuously grew.The fluid and electromagnetic anomalies were dominant in the northern edge of the North China Craton.The number of these anomalies increased first,then decreased.In the surrounding areas of the South China Craton,geophysical anomalies were mainly quasi-synchronous.In the light of the mechanism of typical anomalies,the evolutionary patterns of the anomalies in long term,medium term,short term,and impending period were discussed.For some anomalies like water level anomaly,earth resistivity anomaly,and deformation velocity anomaly,their evolutionary characteristics in each stage were consistent with the variation of the stress conditions according to the sub-instability model.