华北联网后天津遥测地震台网监测能力和定位精度分析

Analysis of detection ability and location accuracy of Tianjin Telemetered Seismic Network after its joining in NCUSN

本文通过天津遥测地震台网在华北遥测地震台网联网后的监控能力的计算和对1992年1—10月地震观测报告的分析处理,得到了一些主要结果。首先,台网的控制能力为:以天津市为中心,半经30km范围内,震级下限为M_L2.0,天津地区及邻区20km内震级下限为M_L2.5。其次,台网的定位精度百分比为:震中误差小于15km的占88％,震中误差15—30km的占8％,震中误差30km的占4％,若以全国地震月报目录定的震中位置为准,天津定的震中位置与其误差小于15km的占81.4％。同时我们还对不同震级,不同震中距(以天津市为中心)的地震的定位精度进行了统计,统计结果为距天津200km范围内的地震,震中误差在15km以内的占91.4％,而距离天津300km以上的地震,震中误差大于30km的占70％。这表明天津台网对远距离地震定位精度较差,这是因为对远距离的地震,天津台网的子台全集中在震中的一侧所致。

By calculation of detection ability of Tianjin Telemetered Seismic Network(TTSN) after its joining in NCUSN and by analysis of the TTSN Observation Reports from January to October, 1992, we obtained the following major results. First, the lower limit of magnitude is M_L 2.0 for the area centered around Tianjin city with a radius of 30 km and M_L 2.5 for the Tianjin region and its vicinity within 20km. Next, for the analized events, the percentages of the various epicenter errors are 88％ (<15km), 8％(15—30kin), and 4％ (30-45km), respectively. Epicenter error of the events smaller than 15 km amount to 81.4％ if the locations given by the National Monthly Earthquake Catalogue of China are taken as the standard for comparison, statistical results show that the epicenter error greater than 30km for the events more than 300km away from Tianjin city amount to 91.4％.