青海李家峡水电站库坝区及附近地震活动特征初步分析

Primary study on the seismicity features in and near Qinghai Lijiaxia Reservoir area

利用青海李家峡水库地震遥测台网试运行7 个月中积累的库坝区及附近从未有过的准确而细致的地震活动资料, 初步讨论了该区域在蓄水初期的地震活动特征。总的来说, 库区以0-6 ～2-0 级的弱小地震活动为特征, 平均月频次为3-8 次, 平均旬频次为1-3 次, 震源深度集中在15 千米以浅的地表。值得引起注意的是, 该区域的地震震中有沿历史上曾有强震发生的拉脊山断裂呈群分布, 且该区域地震旬频次的增加表现出与库水水位的上升相呼应的关系。这是否意味着该水库存在着诱发地震的危险性, 尚待进一步研究确认。

We give a preliminary study on the seismicity of Qinghai Lijiaxia Reservoir area at the filled beginning using the earthquake records occurred in and near the reservoir area Generally speaking,the seismicity around reservoir area is characterised by those small earthquakes of M L 0 6～2 0 with an average earthquake frequency of 3 8 per month and 1 3 per ten days Their focal depths concentrate on the underground of less than 15 km Earthquakes may be induced by filled Lijiaxia Reservoir