提高地震定位精度新方法的研究
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摘要
根据现有台网的分布密度、仪器配置的状况和目前震相判读精度提出了一些新的措施来提高地震定位的效率和精度。主要思想有采用“全局搜索和单纯形综和求解法”求解方程的极值，计算中考虑地球曲率，并做椭球校正。采用“翻台法”来改善目标函数、实现“目标函数拉伸”的思想、控制解域和自行调整发震时刻提高求解的稳定性和精度。采用“模拟退火法”的物理性质来控制试错解的跨越长度，提高求解效率和解的分辨精度。采用区域走时表加台站校正值的思想来减小速度模型的复杂性。采用ＰＴＤ方法和ｓＰｎ－Ｐｎ方法来求震源深度。在地震定位过程中显示地图经纬度，同步演示定位过程及结果。同时还在屏幕上显示传统的交切结果以帮助分析人员判定定位结果的可靠性。区域走时表采用地壳曲面模型，允许模型带有低速层，各层具有梯度，且不限层数，自动使用台站校正值并给出定位误差。根据上述思想和不同的需要分别编制了地方、区域台网定位程序，全国、全球地震定位程序，极远震定位程序用于速报和专门用于研究的地震定位程序。这些程序还带有求震源深度和震级的功能。对于专门进行地震定位研究的工作，还提供了绘制地震定位误差二维等值线图和三维误差分布图的功能。
According to the density and distribution condition of instrument allocation of the now existing networks and the phase interpretatoin accuracy at present, this paper puts forward new measures to raise earthquake locatoin efficiency and accuracy. The main ideas are using the "solving method of overall search and pure track sum" to solve the extreme value of equation. The earth curvature is considered in calculation and elliptical correction is made; using "roll over method" to improve object function, realize the idea of "extension of object function", control the solution area, and actively adjust earthquake occurring time to raise the stability and accuracy of solution; using physical property of "simulated annealing method" to control the span length of trial and error solution, raise the solving efficiency and the rosolution accuracy of solution; using regional travel lime takles and correctoin values of stations to reduce the complexity of velocity model; using PTD method and sPn Pn method to solve focal depth. Display longitude and latitude of the map during earthquake location process and simultaneously demonstrate the location process and results. At the same time, traditional intersect result is displayed on the screen to help the analysers judge the reliability of location result. Regional travel time table adopts curved surface model of the crust. The model is allowed with low velocity layer, each layer has gradient, and the number of layers is not limited, automatically using correction value of the station and giving the location error. According to the above ideas and different requirements, programs are written separately for local and regional network location, national and global earthquake location, far distant earthquake location programs for rapid momitoring, and earthquake location programs for special research. These programs also have the functions of solving focal depth and magnitude. For special earthquake location research, it also provides function to draw two dimensional isogram drawings of earthquake location error and distribution drawings of three dimensional error.
According to the density and distribution condition of instrument allocation of the now existing networks and the phase interpretatoin accuracy at present, this paper puts forward new measures to raise earthquake locatoin efficiency and accuracy. The main ideas are using the "solving method of overall search and pure track sum" to solve the extreme value of equation. The earth curvature is considered in calculation and elliptical correction is made; using "roll over method" to improve object function, realize the idea of "extension of object function", control the solution area, and actively adjust earthquake occurring time to raise the stability and accuracy of solution; using physical property of "simulated annealing method" to control the span length of trial and error solution, raise the solving efficiency and the rosolution accuracy of solution; using regional travel lime takles and correctoin values of stations to reduce the complexity of velocity model; using PTD method and sPn Pn method to solve focal depth. Display longitude and latitude of the map during earthquake location process and simultaneously demonstrate the location process and results. At the same time, traditional intersect result is displayed on the screen to help the analysers judge the reliability of location result. Regional travel time table adopts curved surface model of the crust. The model is allowed with low velocity layer, each layer has gradient, and the number of layers is not limited, automatically using correction value of the station and giving the location error. According to the above ideas and different requirements, programs are written separately for local and regional network location, national and global earthquake location, far distant earthquake location programs for rapid momitoring, and earthquake location programs for special research. These programs also have the functions of solving focal depth and magnitude. For special earthquake location research, it also provides function to draw two dimensional isogram drawings of earthquake location error and distribution drawings of three dimensional error.
引文
李平，朱元清．1993．上海及邻近地区测震台网历史监测能力．地震地磁观测与研究，14（1）：1～7唐国兴．1979．用计算机确定地震参数的一个通用方法．地震学报，1（2）：186～196张少泉．1978．近震分析．地震出版社，186～225朱元清．1989．上海电信传输地震台网监测能力及定位精度．地震地磁观测与研究，10（3）：27～32朱元清，石耀霖，李平．1990．一种确定地震深度的新方法．地震地磁观测与研究，11（2）：4～12朱元清，范长青，浦小峰．1995．南黄海地震序列时空参数的精细测定和分析．11（1）：53～61赵仲和．1983．多重模型地震定位程序及其在北京台网的应用．地震学报，5（2）：242～254赵仲和．1983．区域地震台网地震定位能力分析．地震学报，5（4）：467～476赵仲和．1983．北京地区地震参数与速度结构的联合测定．地球物理学报，26（2）：211～222赵仲和，姜燕，张力群．1993．地震定位程序BLOC及其变体．地震地磁观测与研究，14（5）：6～9AndrzejKijko，1982．AStatisticalModelforEstimatingtheAcuracyofEventLocationAppliedtoaNetworkofScandi－navianStations，PAGEOPH，120：187～195LeeWHK，etal．，唐美华译．1984．微震台网的原理及应用，地震出版社
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