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  • LIANG Hui, XIANG Yang, YAN Long, ZHU Cheng-Ying
    Inland Earthquake. 2023, 37(2): 152-163. https://doi.org/10.16256/j.issn.1001-8956.2023.02.005
    Based on the “China Earthquake Examples” (1966~2018), the characteristics of ground fluid precursor anomalies before earthquakes in Xinjiang region were systematically analyzed, and the prediction effectiveness of different magnitude ranges was tested for each measurement item. The results show that the number of ground fluid anomalies in Xinjiang is mostly concentrated in 100~200 km, and the duration of anomalies is mostly within half a year before the earthquake; The average number of ground fluid anomalies in Xinjiang during earthquakes with MS≤6.5 is 4; The monthly frequency of anomalies before earthquakes is mainly manifested as a “sustained growth” type and a “first increase then decrease” type; Xin10 and Xin04 measuring points are abnormal “sensitive points” in ground fluid observation points in Xinjiang, and their location and vicinity can be considered as structural “sensitive areas”; The R value scoring method was used to test the prediction effectiveness of each measurement item, and the results showed that the R value results of different magnitude ranges were conducive to analyzing and extracting anomaly indicators suitable for the corresponding magnitude.
  • ZHENG Xue-gang, MA Xue-jun, ZHAO Peng-bi
    Inland Earthquake. 2023, 37(2): 172-179. https://doi.org/10.16256/j.issn.1001-8956.2023.02.007
    Based on the teleseismic waveform data recorded by Xinyuan Seismic Station from 2016 to 2020 with a Epicentral distance of 30°~90°, the teleseismic P-wave receiver function is extracted by time domain iterative deconvolution method, and the crustal thickness and Poisson’s ratio under the station are calculated by using a generalized receiver function H-k stacking method H-k-c with harmonic correction. The results indicate that the H-k-c method significantly improves the estimation of crustal thickness and Poisson’s ratio, with an average crustal thickness of about 56.3 km and a Poisson’s ratio of about 0.25 below Xinyuan Seismic Station.
  • Mulatijiang Abulaiti, Gao Ge
    Inland Earthquake. 2023, 37(2): 180-188. https://doi.org/10.16256/j.issn.1001-8956.2023.02.008
    Polarization value of the vertical component of FHDZ-M15 geomagnetic second data at Kashi Station is calculated by the polarization method, and the relationship between the abnormal amplitude of the polarization value, Epicentral distance, abnormal duration and the corresponding earthquake magnitude is quantitatively studied. The results show that: ① there is a good correspondence between the high polarization value anomaly and MS≥5.0 earthquakes in the surrounding area of the station within the next 4 months, with high value anomalies lasting mostly for 3~6 days; ② The relationship between the magnitude of the corresponding earthquake and the Epicentral distance is quasi linear, and the correlation coefficient reaches 0.791; ③ According to the analysis of Epicentral distance, the significant relationships are 0~150 km and 150~250 km, and the correlation coefficients of anomaly duration and corresponding earthquake magnitude are 0.645 and 0.702 respectively. The correlation coefficient between anomaly amplitude and magnitude is 0.717 within 150~250 km. Over 250 km, the correlation coefficient between Epicentral distance and magnitude is 0.687; ④ According to the magnitude analysis, MS6.0~6.9, the magnitude is moderately negatively correlated with Epicentral distance, and the correlation coefficient is -0.685.
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