基于EMR方法的内蒙古测震台网监测能力

Monitoring Capacity of Seismic Network in Inner Mongolia Region Based on EMR Method

为考察内蒙古及邻区地震监测能力的时空分布特征,并为该地区的地球科学研究和测震台网的进一步优化布局提供科学参考,根据内蒙古测震台网发展的各历史阶段,分析了地震定位台站数据和台站张角的时空分布,并采用完整性震级范围(EMR)方法,研究了最小完整性震级Mc的时空分布特征.结果表明,台站张角和台站数的时空演化能够定性、客观地反映内蒙古测震台网台站数量由少到多,地震监测能力由弱到强逐步完善的发展过程.而EMR方法给出的Mc时空分布,可定量描述内蒙古测震台网各历史时期Mc时空的监测能力变化.结果显示,1990—2001年的模拟记录期间,呼和浩特地区Mc值约为ML2.0,与蒙古交界地区可达ML3.0以上.2002—2007年的模拟和数字化并行期间,内蒙古中西部以及与外省交界地区监测能力有所提升.2008—2012年的"十五"数字台网运行期间,测震台网的建设有效克服了行政区划狭长、台站布局不合理的现状,绝大多数地区ML2.2以上地震基本完整.相关研究将为内蒙古地区地震观测系统的进一步优化布局、地震观测产品用于地震预测预报研究和地震危险性分析提供重要的参考依据.

In this paper monitoring capacity of Inner Mongolia seismic network is evaluated, aiming at offering information for scientific layout of seismic stations. We analyze the temporal and spatial character of record stations number, maximum station coverage azimuth and minimum magnitude of completeness （Me） based on the observation reports and catalogues in Inner Mongolia regions. The results reflect the development of the monitoring capacity. The Mc in Hohhot region was around ML2.0 and over ML 3.0 in the juncture of Mongolia and Inner Mongolia during ＂analogy＂ era （1990-2001）. The monitoring capacity has been improved in the Midwest of Inner Mongolia region and the adjacent areas during ＂analogy digital parallel＂ era （2002- 2007）, with Mc reaching as low as ML2. 2 in most of Inner Mongolia and its adjacent areas during ＂digital＂ era and the 10th five- year project period （2008-2012） because the layout of stations is more reasonable and the influence of long narrow region shape has been overcome. This study facilitates the future seismic activity analysis and the seismic hazard assessment in this region.