摘要
计算了１９７９—１９８７年发生在北纬３４°３０＇一３６°＇１０，东经１１５°—１１７°４５＇范围内１４８次ＭＬ≥２０级地震的波速比值，分析了１９８３年菏泽５．９级地震前后源区与场区波速比的时空变化特征及其差异，对计算结果进行了ｔ检验，源区和场区波速比的时空变化及ｔ检验结果表明，５．９级地震前，源区波速比存在比较明显的下降一低值一恢复过程。场区则表现了５．９级地震临震前的低值异常。５．９级地震后源区和场区的波速比计算结果一致，时空变化均为正常。
In this paper, the VP/VS ratios of 148 earthauakes of ML≥2. 0 occurred in the range of 34°30' 36°10' north latitude and 115°117°45' east longitude in 1979-1987 are calculated, the time and space variational characteristics of VP/Vs ratio in source zone and field zone and its difference before and after the 1983 Heze MS. 9 earthquake are analyzed and the calculated results are tested. The time and space variation of Vp/Vs ratio in source zone and field zone and the tested result show that before the M5. 9 earthquake the Vp/Vs ratio in source zone showed a clear process of decrease-low walue-recovering The field zone showed a low value anomaly immidiately before the M5. 9 earthquake. The calculated result of the Vp/vs ratio in source zone and field zone is consistent after the M 5. 9 earthquake, both time and space variations are normal.
出处
《华北地震科学》
北大核心
1994年第1期46-53,共8页
North China Earthquake Sciences
关键词
地震
震级
地震波
源区
场区
Heze earthquake, Vp/Vs ratio, source zone and field zone
