青海省河南M_S5.1和玛沁M_S5.0地震后库玛断裂带的地震活动趋势研究

A STUDY ON EARTHQUAKE TREND OF KUMA FAULT ZONE AFTER THE HENAN M_S5.1 AND MAQIN M_S5.0 EARTHQUAKES IN QINGHAI PROVINCE

根据地震活动特征、大武地震台尾波持续时间及长宁、湟源和西宁 3个台水氡异常变化 ,讨论了 1 999年河南MS5 .1和玛沁MS5 .0地震发生后库玛断裂带的地震活动趋势 .结果表明 ,河南—玛沁地区的中强地震活动与库玛断裂带上的强震活动有明显的对应关系 ;在库玛断裂带中东段存在一个由ML ≥ 3.0地震围成的空区 ;上述2次地震发生后大武地震台尾波持续时间异常依然存在 ,长宁、湟源和西宁台水氡趋势异常仍然持续 .

The earthquake trend of Kuma fault zone after the Henan M S5.1 and the Maqin M S 5.0 earthquakes is analyzed and discussed on the basis of seismicity,anomalous changes of coda lasting time by Dawu seismic station and radon contents in groundwater by Changning,Huangyuan and Xining stations.The results show that there is an obvious corresponding relation between mid strong earthquakes in Henan—Maqin area and strong earthquakes along Kuma fault zone.There is a gap by M L≥3.0 earthquakes at middle section of the Kuma fault zone.Anomaly of the coda lasting time still exists and the trend anomalies of radon content in groundwater still continue.Therefore,there is a background of strong earthquake along the Kuma fault zone after the two earthquakes.