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ISSN 2096-7780 CN 10-1665/P

沂沭带附近流动重力显著变化点分析及其地震预报效能评估

Evaluation of earthquake prediction efficiency of significant change point of mobile gravity near Yishu zone under weak earthquake background

  • 摘要: 重力场的显著变化区域周边通常伴有变化明显的测点。为对沂沭带附近重力场变化开展除常规分析外的进一步研究,本文在区域变化分析的基础上,对显著变化区域周边测点的时序变化进行了详细分析,验证其与周边地震的对应性。计算了沂沭带附近2022年7月分别与前一期及2015年8月的数据差值并通过绘图选取了区域变化显著的周边测点,分析其时序变化与周边地震的初步对应,并采用地震预报效能评估软件进行了长期数据的分析验证。分析后认为:① 广饶附近受地面沉降影响较大,昌邑附近受地下潜水层水位变化影响较大,枣庄及张庄等显著变化测点与周边地震有一定对应关系;② 5个显著变化测点在阈值类、趋势转折类共10个评估测项中仅有1项评估不合格,可以初步判定,沂沭带附近的显著变化测点对测点周边100 km范围的ML3.0左右地震具有较好的监测效能。

     

    Abstract: The area around which a gravitational field changes significantly is usually accompanied by measurement points with significant changes. To carry out analysis of the gravity field variation around the Yishu zone based on the analysis of regional variation, the temporal variation of the measuring points around the significant change area was analyzed in detail to verify its correspondence with surrounding earthquakes. In this study, the data difference between July 2022 and the previous period and August 2015 near the Yishu zone was calculated, and peripheral measuring points with significant regional changes were selected through mapping to analyze the preliminary correspondence between their time series changes and the surrounding earthquakes. The long-term data were analyzed and verified using an earthquake prediction efficiency evaluation software. The results showed that: ① The Guangrao area is affected by ground subsidence, the Changyi area is affected by changes in groundwater level, and the Zaozhuang and Zhangzhuang areas have some correspondence with the surrounding earthquakes. ② Only one out of ten evaluation items in the threshold category and trend-turning category of the five significant change measurement points failed to meet the evaluation criteria. It can be preliminarily concluded that the significant change measurement points near the Yishu zone have a good monitoring efficiency for ML3.0 earthquakes within 100 km of the measurement points.

     

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