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The relationship research between the anomalous change of the low degree gravity field coefficient J2 and the seismic activity
|Authors:||Duan Pengshuo; Hao Xiaoguang; Liu Genyou; Zhang Yu|
|Author Affiliations:||Primary: |
Chinese Academy of Sciences, Institute of Geodesy and Geophysics, Wuhan, China
University of Chinese Academy of Sciences, China
|Volume Title:||Dixue Qianyuan Earth Science Frontiers|
|Source:||Dixue Qianyuan = Earth Science Frontiers, 20(6), p.54-66. Publisher: China University of Geosciences, Beijing, China. ISSN: 1005-2321|
|Note:||In Chinese with English summary. 32 refs.; illus., incl. 1 table|
|Summary:||There were two anomalous changes that happened in the low degree gravity field coefficient J2 during the 1992-2011, in two periods of about 1997-2000and 2007-2010; according to the earthquake catalog that reported by CNS, all the MS≥3.0seismic data in China Mainland during 1990-2012 have been collected to make the preliminary analysis of the relationship between the J2anomalous change and the seismic activity. This paper makes statistical analysis of the total number of the shallow-focus MS≥5.0, MS≥6.0 earthquakes(0≤h≤70km) and of the intermediate focus MS≥3.0, MS≥3.5, MS≥4.0 earthquakes (70≤h≤300km) respectively to establish the time series of frequencies of earthquakes. This paper has made detailed comparison between the time series of frequencies of earthquakes and J2, and the results are as follows: (1) the shallow focus earthquake activity has three peaks, the first peak time and the second peak time are consistent with "98anomalous" and "07anomalous" respectively, and the third peak time is consistent with the transition period of Earth's rotation rate; (2) there are differences between the intermediate focus and shallow-focus earthquake activity, the former has only two obvious peaks, and the first peak time is consistent with "98anomalous" the second peak time appears the delay phenomenon relative to "07 anomalous" however, the wavelet multiresolution analysis shows that the wavelet detailed coefficients of the time series of frequencies of earthquakes changed significantly in the time period that is perfectly consistent with "07anomalous"; (3) the ratio of MS≥7.0earthquakes that happened during the time of J2 anomalous changing is 62.5%, and their latitude distribution is almost near the node line of J2 about 35.3°N.These results show that J2 anomalous change may lead to strong seismic activity in China Mainland, the transition of Earth's rotation rate could significantly affect the shallow-focus earthquake activity but not the intermediate-focus earthquake activity. In the end, this paper studies the relationship between J2 variations and seismic activity from the aspects of Earth gravity and the relationship between J2 and the Earth rotation. The results are valuable to us for further understanding the process of earthquake pregnancy and researching earthquake prediction.|
|Subjects:||Earth; Earthquake prediction; Earthquakes; Gravity anomalies; Gravity field; Rotation; Seismicity; Seismology; Statistical analysis; Time series analysis; Asia; China; Far East|
|Copyright Information:||GeoRef, Copyright 2021 American Geosciences Institute.|
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