测震台网监测能力评估技术的比较研究

发布时间：2018-09-10 10:11

【摘要】：作为一项基础和重要的问题,对测震台网地震监测能力的科学评估,是进一步优化测震台网布局、提升重点地区监测能力和满足地球科学研究与监测预报业务需求的关键。我国测震台网经过半个世纪的发展,尤其是“十五”数字化的改造,监测能力和台网建设得到质的飞跃。目前,中国地震台网建设仍处于快速发展阶段,科学研究、地震监测预报,以及正在设计中的“国家地震烈度速报与预警工程”项目的建设等,均对地震台网监测能力的科学评估提出更高要求。论文针对中国地震台网的监测能力评估中的如下问题开展研究:一是,考虑中国地震台网(CSN)的实际建设和运行情况,如何科学评估地震台网现有地震监测能力;二是,影响和制约中国地震台网监测能力提升的原因有哪些,如何才能满足地震台网最优监测能力提升需求;三是,多种监测能力评估方法为评估工作提供更多选择,如何选择科学有效的评估方法用于实际工作。为解决上述三个问题,论文分别选用全国范围(70°～140°E,5°～55°N,涉及相关台站1001个)和南北地震带(19°～45°E,94°～110°N,涉及相关台站289个)地区为研究区,利用中国地震台网中心提供的“全国统一正式编目”2008/10/01～2015/09/17的地震观测报告开展相关工作。在技术方法上,分别使用了“基于概率的完整性震级”(PMC)方法、“完整性震级范围”(EMR)方法,以及地震台网常规使用的“震级-最大距离”方法等,分别开展了方法的引入研究、比较研究,以及发展了新的台站运行效能的评价方法。获得的主要认识如下:一是,基于PMC方法在利用地震台网实际产出资料的客观评估、不依赖震级分布关系、可对弱地震活动或无地震活动区域评估等技术优势,引入了 PMC方法,并对中国地震台网“十五”项目建成后的监测能力进行了客观评估。结果显示,当前我国东西部地震监测能力差异较大,西部地区与华北、东南沿海等东部地区相比地震监测能力相对较弱,尤其是青藏高原南部地区监测能力仅在4.5级左右,近海海域地震监测能力约在3.5级左右。青藏高原、边疆海域等地较弱的监测能力问题,急需引起高度重视。二是,为更好满足地震台网最优监测能力提升需求,本研究设计“地震检测能力评分表”,并分别对中国地震台网1001个台站进行检测能力量化打分,并对评分结果的统计特征和空间分布进行分析。此外,研究中通过设定“最佳”地震监测能力目标函数对中国地震台网以及未来国家地震烈度速报与预警工程项目建成后的地震监测能力进行模拟预估,并分别给出地震台网监测能力的理论提升结果。研究结果表明,148个国家台的台站检测能力评分系统高于853个区域台,边疆部分地区(如:新疆、青海、西藏、内蒙古等)以及东南沿海福建等地台站地震检测能力明显高于东部相对台站密集区,说明不同台站在地震事件拾取完备程度上存在差异,可一定程度反映各个台站的运行管理水平,对未来改进测震台网年度运维考评方式,有一定参考借鉴意义;模拟结果显示,在现有台站基础上,通过台站优化改造和提升运维管理水平,可显著提升对内蒙古西部和贵州等大部分地区的地震监测能力。此外,还分别从“底线”的监测能力和“最佳”的监测能力两个角度,对国家烈度速报和预警工程项目建成后的理论监测能力进行了模拟预估。三是,针对地震监测能力评价方法多、评估结果差异大的问题,论文选用了PMC方法、EMR方法和中国地震台网常用的震级-最大距离方法,以南北地震带地区为研究区进行了比较研究。论文统一采用至少3个台站记录的地震资料,对以往关注不够的地震观测资料质量一致性问题加以考虑。结果发现,三种方法评估结果差异明显,南北地震带个别地区dMc甚至可达2.0级;三种方法在统计均值上呈现McEMRMpMr趋势;震级-最大距离方法得到的监测能力分布主要取决于台站密度;南北地震带32°N以北,PMC方法评估结果相比其他两种方法显示更高的地震监测能力。通过对各个地震台站检测能力评分发现,PMC方法结果显著不同于其他方法结果主要是由于台站运维水平和对记录地震的分析完整程度造成,这两项因素在地震监测能力评分中应加以考虑;地震资料的遴选条件不同,可能会直接影响EMR方法计算结果,以往常用的包括单台地震记录的地震目录可能会产生McEMR结果低估现象。考虑到地震台网运行实际情况和不同评估方法的计算原理,本研究推荐更为合理的PMC方法用于地震监测能力评估工作。论文针对中国地震台网监测能力评估中的三个问题开展研究并获得的研究结果,将可对科学评估现有监测能力和选择评价方法、进一步完善边疆海域地区地震监测布局、改进测震台网考核评价方法、预估国家地震烈度速报与预警工程建成后的监测能力等多方面有科学借鉴意义。
[Abstract]:As a basic and important problem, the scientific evaluation of seismic monitoring capability of seismic network is the key to further optimize the layout of seismic network, enhance the monitoring capability of key areas and meet the needs of Geoscientific research, monitoring and prediction. At present, the construction of China's seismic network is still in a rapid development stage. Scientific research, earthquake monitoring and prediction, as well as the construction of the "National Earthquake Intensity Rapid Forecasting and Early Warning Project" under design all put forward higher requirements for the scientific evaluation of seismic network monitoring capacity. In view of the following problems in the evaluation of the monitoring capability of China seismic network: first, considering the actual construction and operation of China Seismological Network (CSN), how to scientifically evaluate the existing seismic monitoring capability of the network; second, what are the reasons that affect and restrict the improvement of the monitoring capability of China seismic network and how to meet the needs of earthquakes? In order to solve the above three problems, the paper chooses the national scope (70 140 E, 5 55 Degree to 45 degrees E, 94 degrees to 110 degrees N, involving 289 related stations) in the study area, using the "National Unified Formal Catalogue" 2008/10/01-2015/09/17 seismic observation reports provided by the China Seismological Network Center to carry out related work. In technical methods, respectively, the "probability-based integral magnitude" (PMC) method and "integral earthquake" method are used. The magnitude range (EMR) method and the "magnitude-maximum distance" method, which are commonly used in seismic networks, have been introduced and studied respectively. A comparative study has been carried out and a new method for evaluating the operational effectiveness of seismic stations has been developed. The main understandings obtained are as follows: First, the objective evaluation based on PMC method using the actual output data of seismic networks has been carried out. The PMC method is introduced to evaluate the monitoring capability of China Seismological Network after the completion of the Tenth Five-Year Plan Project. The results show that there is a great difference in the seismic monitoring capability between the East and the west of China, and the west of China is different from the north and the east of China. Compared with the eastern areas such as the South coast, the seismic monitoring ability is relatively weak, especially in the southern part of the Qinghai-Tibet Plateau, which is only about 4.5, and the offshore area, which is about 3.5. In order to improve the monitoring capability, this study designed a "seismic detection capability scoring table" and quantified the detection capability of 1001 stations in China seismic network, and analyzed the statistical characteristics and spatial distribution of the scoring results. The results show that the scoring system of the detection ability of 148 national stations is higher than 853 regional stations and some frontier areas (e.g. Xinjiang, Qinghai and West China). The seismic detection ability of the stations in Tibet, Inner Mongolia and Fujian along the southeast coast is obviously higher than that of the relatively dense areas in the east. This shows that there are differences in the degree of completeness of seismic events picked up by different stations, which can reflect the operation and management level of each station to a certain extent, and can be used as a reference for improving the annual operation and maintenance evaluation method of seismic network in the future. The simulation results show that, on the basis of the existing stations, the seismic monitoring capability of the western Inner Mongolia and Guizhou can be significantly improved by optimizing the transformation and upgrading the operation and maintenance management level of the stations. Thirdly, in view of the problems of many evaluation methods of seismic monitoring capacity and large differences in evaluation results, PMC method, EMR method and magnitude-maximum distance method commonly used in China seismic network are selected and compared in the study area of North-South seismic belt. The results show that there are obvious differences in the evaluation results of the three methods. The dMc of some areas in the North-South seismic belt can even reach 2.0. The three methods show a trend of McEMRMpMR in the statistical mean value. The monitoring capability distribution obtained by the maximum distance method mainly depends on the station density; north of the North-South Seismic Belt 32 N, PMC method shows higher seismic monitoring capability than the other two methods. These two factors should be considered in the evaluation of seismic monitoring capability. Different selection conditions of seismic data may directly affect the calculation results of EMR method. Previous catalogues including single seismic records may result in underestimation of McEMR results. According to the actual situation of seismic network operation and the calculation principle of different evaluation methods, this study recommends a more reasonable PMC method for seismic monitoring capability evaluation. The evaluation method can be used for reference in many aspects, such as further improving the layout of seismic monitoring in the border areas, improving the evaluation method of seismic network, and predicting the monitoring ability of the national earthquake intensity quick report and early warning project after completion.
【学位授予单位】：中国地震局地球物理研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P315.78

【参考文献】