薛 丁 张建业 赵爱萍

（中国呼和浩特010010内蒙古自治区地震局）

海城地震窗地震活动异常提取及其预报效能＊

薛 丁 张建业 赵爱萍

（中国呼和浩特010010内蒙古自治区地震局）

一个时间序列可以分解为趋势周期（含季节周期）部分和不规则随机部分.趋势周期部分是序列的潜在部分，它反映了增长、下降和周期影响的长期变动规律，具有确定性或可预测性；不规则随机部分包含残差、突然等因素引起的突变量，具有不可预测性.当趋势周期部分被确定后，它可通过计算得到.本文研究了1975年海城MS7.3地震孕育、发生的断裂构造背景，合理地确立地震窗的范围来选取地震资料.在此基础上，对海城地震窗地震月频次时间序列进行分解，采用自回归单整移动平均（ARIMA）模型确定了趋势周期部分，并计算得到了不规则随机部分；分析了不规则随机部分中的突变量异常特征对华北地区MS6.0和地震窗附近MS5.0以上地震的反应.结果表明，该异常特征具有较高预测效能，对地震预测有较好参考价值.

地震窗 地震断层 地震活动异常 预报效能

Abstract：An original time series signal can be decomposed into a trend－cycle，including seasonal cycle，component and an irregular component.The trendcycle part is defined as underlying level of the series，and is a manifestation of medium－long term variation influenced by fluctuation and cycles referring to generally deterministic or predictable change of a series.The irregular component contains the residual variation and random abrupt changes，etc.，being unpredictable.Knowing the trend－cycle component，the irregular part can be calculated.Based on the investigation of the faults associated with the 1975 Haicheng MS7.3 earthquake，this study reasonably determined the area window of the Haicheng earthquake series.Then the time series of monthly earthquakesin the Haicheng seismicity window was decomposed.The trend－cycle component of the series was determined using ARIMA（atuo regression integrated moving average）model and the irregular variation was also extracted.The reaction of the anomalous abrupt variation to the MS≥6.0 earthquakes in North China and MS≥5.0 earthquakes near the seismicity window was analyzed.The result shows that the anomaly of abrupt seismicity variation may be taken as an indicator with prediction ability.This is of significance in earthquake prediction.

Key words：seismicity window；earthquake fault；seismicity anomaly；prediction ability

引言

一个时间序列，可以分解为趋势周期（其中也包括季节波动循环周期在内）部分和不规则随机部分.趋势周期部分是序列的潜在部分，它反映了增长、下降和周期影响的长期变动规律，具有确定性或可预测性；不规则随机部分是趋势周期部分被确定后的参差以及由不可预测之突然、偶然等因素引起的突变量变动.地震……