地震研究

1970年以来东北地区共发生13次5.0级以上地震,其中8次地震在时间和空间上相对独立。通过系统研究东北及其邻区这8次中强地震前的小震,发现这些中强地震前存在比较明显的小震增强现象。结合东北地区小震活动的特点,提出根据小震活动空间格局是否改变统计小震频度的方法,并进行了初步的应用。结果表明:利用新方法统计小震的频度更能突出中强地震前的小震频度异常,能够有效的提取东北地区中强地震前的中短期异常指标。

Since 1970,13 earthquakes of M≥ 5.0 occurred in the Northeast China,of which 8 medium-strong earthquakes are independent in space and time.Having studied small earthquakes before the 8 medium-strong earthquakes systemically,we found that these small earthquakes activities increased.Combining with characteristics of the small earthquake activities in the Northeast China,we proposed and applied the new method whether the spatial changing pattern of small earthquake activities change the small earthquake frequency.The result showed that the small earthquake frequency calculated by using new method could pick up anomaly frequency of small earthquakes before medium-strong earthquake.We could get medium-short-term abnormal indexes effectively before the medium-strong earthquakes in Northeast China.

引言
1 东北地区中强地震前小震活动增强
2 讨论
3 结论

图1 林甸地震前不同扫描半径的小震(ML≥2.0)频度曲线<br/>Fig.1 Frequency curves of small earthquakes(ML≥2.0) in different scanning radius before Lindian earthquake

图1 林甸地震前不同扫描半径的小震(ML≥2.0)频度曲线
Fig.1 Frequency curves of small earthquakes(ML≥2.0) in different scanning radius before Lindian earthquake

图2 小震频度异常统计方法示意图<br/>Fig.2 Schematic diagram of statistical method of small earthquakes frequency anomaly

图2 小震频度异常统计方法示意图
Fig.2 Schematic diagram of statistical method of small earthquakes frequency anomaly

图3 2003年巴林左旗5.9级地震前小震频度异常曲线(a)原始频度曲线;(b)新方法频度曲线<br/>Fig.3 Frequency anomaly curve of small earthquakes before Balinzuoqi M5.9 earthquake in 2003(a)Original frequency curve;(b)Frequency curve by new method

图3 2003年巴林左旗5.9级地震前小震频度异常曲线(a)原始频度曲线;(b)新方法频度曲线
Fig.3 Frequency anomaly curve of small earthquakes before Balinzuoqi M5.9 earthquake in 2003(a)Original frequency curve;(b)Frequency curve by new method

图4 1999年岫岩5.4级地震前小震频度异常(a)原始频度曲线;(b)新方法频度曲线<br/>Fig.4 Frequency anomaly curve of small earthquakes before Xiuyan M5.4 earthquake(a)Original frequency curve;(b)Frequency curve by new method

图4 1999年岫岩5.4级地震前小震频度异常(a)原始频度曲线;(b)新方法频度曲线
Fig.4 Frequency anomaly curve of small earthquakes before Xiuyan M5.4 earthquake(a)Original frequency curve;(b)Frequency curve by new method

图5 东北地区中强震前小震频度异常曲线(a)原始频度曲线;(b)新方法频度曲线<br/>Fig.5 Frequency anomaly curve of small earthquakes before medium-strong earthquakes in Northeast China(a)Original frequency curve;(b)Frequency curve by new method

图5 东北地区中强震前小震频度异常曲线(a)原始频度曲线;(b)新方法频度曲线
Fig.5 Frequency anomaly curve of small earthquakes before medium-strong earthquakes in Northeast China(a)Original frequency curve;(b)Frequency curve by new method

图6 巴林左旗地震前不同空间范围的小震频度异常曲线(a)3°×3°频度曲线;(b)1.5°×1.5°频度曲线<br/>Fig.6 Frequency anomaly curve of small earthquakes in different space range before Balinzuoqi earthquake(a)Frequency curve of 3°×3°;(b)Frequency curve of 1.5°×1.5°

图6 巴林左旗地震前不同空间范围的小震频度异常曲线(a)3°×3°频度曲线;(b)1.5°×1.5°频度曲线
Fig.6 Frequency anomaly curve of small earthquakes in different space range before Balinzuoqi earthquake(a)Frequency curve of 3°×3°;(b)Frequency curve of 1.5°×1.5°

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备注

引言

1 东北地区中强地震前小震活动增强

2 讨论

3 结论

期刊信息