区域地震台网远震定位问题探讨——华北地区遥测地震台网联网论文续三

用北京遥测地震台网的远震资料应用TEL92远震定位程序对66个地震重新计算,将计算结果与《PDE目录》对比分析,从中得出有益的结论.     

地方小型地震遥测台网的技术要求

以厦门地震遥测台网为例,阐述了由地方政府投资的小型台网在布局及设备性能上的技术要求。通过对台网实测资料的分析,检验了台网的监测能力,结果表明,距台网中心分别为１００～１５０ｋｍ和４５０ｋｍ范围内（包括台湾东带）,发生的ＭＬ２．５和３．５级以上地震都处于台网的有效监测范围。     

长河坝—黄金坪水库区域地震台网监测能力分析

位于四川省甘孜藏族自治州康定市内大渡河干流的长河坝—黄金坪水电站,为大渡河流域开发中,以长河坝、大岗山、瀑布沟等形成主要梯级格局开发方案中,"三库22级"水电站中的第10和11级电站,其地震监测台网也采用梯级设计方式,长河坝—黄金坪上下游水库地震监测台网统一设计、建设及监测,共享同一地震监测能力。通过对监测设备的技术指标、台基地噪声水平和震级—频度对数关系的分析,结果表明,长河坝—黄金坪水库区域地震固定台站建成后,地震监测能力达到并优于设计的理论监测能力,地震监测震级达到下限为M_L 0.5的设计要求。     

提高地方地震台网地震速报水平初探

总结了西昌遥测地震台网地震速报处理技术经验，针对地方台网地震速报中常出现的地震参数误差提出了改进思路。     

Detectability and reliability analysis of the local seismic network in Pakistan

The detectability and reliability analysis for the local seismic network is performed employing by Bungum and Husebye technique.The events were relocated using standard computer codes for hypocentral locations.The de-tectability levels are estimated from the twenty-five years of recorded data in terms of 50%,90%and 100% cumu-lative detectability threshokls,which were derived from frequency-magnitude distribution.From this analysis the 100%level of detectability of the network is ML=1.7 for events which occur within the network.The accuracy in hypocentral solutions of the network is investigated by considering the fixed real hypocenter within the network.The epicentral errors are found to be less than 4km then the events occur within the network.Finally.the prob-lems faced during continuous operation of the local network,which effects its detectability,are discussed.     

黑龙江省地震台网的监测能力

介绍黑龙江省数字化地震台网建设的概况，对黑龙江省的监测能力进行计算和绘制，说明黑龙江省台网的监测能力达到了预期的目的和要求，为黑龙江省的防震减灾以及监测预报工作提供了有力的依据和基础数据。     

区域地震台网历史震相数据整合与共享服务

区域地震台网震相数据是区域地震台网产出的重要成果,是开展地球科学研究的重要资料。整理全国31个省份1973—2008年区域地震台网纸质震相报告和地震卡片,按统一格式录入震相数据,建立数据共享服务系统。文中系统阐述区域地震台网的发展过程、历史震相数据的整合、地震观测报告的主要内容及震级的测定方法,并介绍了历史震相数据共享服务系统和快速索引下载方法,为科研人员提供共享服务。     

Site survey and assessment for the planned seismogeodynamic monitoring network in the Republic of Armenia

We present results of a detailed analysis of data obtained from seismic geodynamic field studies conducted at proposed sites for the development of advanced seismic monitoring stations in the Republic of Armenia. These studies aim to determine the background seismic and geodynamic noise level around such sites. Finally, based on the received data and international standards, nine survey points were classified into respective classes according to their noise level. We also calculated minimum significant earthquake magnitude detectable by the proposed seismic network in different regions of Armenia and mapped it based on recorded regional earthquakes. The resulting map indicates that the proposed seismic monitoring network will provide homogenous initial data for the various seismically active regions of the territory of the Republic of Armenia.     

On the seismic regime network method

In this paper, based on the previous study of practical use of seismic regime windows and seismic regime belts, the problem of establishing a “seismic regime network” consisting of “windows” and “belts” is further posed and discussed according to the observed fact that many “windows” and “belts” make responses to one earthquake. For the convenience of usage, the “seismic regime network” is divided into two classes, the first class and the second one. The former can be used in tendency prediction for long-term seismic activity in a large area, the latter used in short-term prediction in a small area. In this paper, after briefly discussing the physical significance of “seismic regime network”, it is pointed out that this simple and easily used method can be used to observe and extract seismic precursory information from a large area before a great earthquake, thus it can provide a reliable basis for the analysis and judgement of seismic regime tendency in time and space. No doult, this method is of certain practical significance. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 161–169, 1991. The English version of this paper is improved by Prof. Shaoxie Xu.     

镜泊湖火山测震台网监测效能评估

2019年镜泊湖火山测震台网新增2个测震台后,共有5个测震观测子台对火山区进行地震监测.利用其观测数据,进行噪声功率谱和监测能力计算,绘制地震监测能力图,并与原测震台网监测能力进行对比分析.研究表明,镜泊湖火山测震台网监测能力得到很大提升,可满足火山地震监测需要.     

甘肃省地震台网监测能力分析

讨论了影响台网监测能力的因素，通过对2000年6月～2003年1月甘肃省地震台网产出的地震目录进行分析，给出了甘肃省地震台网监测能力，对台网监测能力弱区进行了划分，提出提高台网监测能力的建议。     

永安无人值守地震台远程网络监控系统

针对永安无人值守地震台设备维护及安全巡视等问题,利用地震台现有网络搭建方式,使用网络摄像机及相应监控系统软件,通过合理配置,实现无人值守地震台远程网络视频监控。该系统的实现,提高了永安地震台管控无人值守台站的能力,对其他地震台有一定借鉴意义。     

区域地震台网的动态监测能力

提出了一种区域台网监测能力的动态估计方法,结果表明,平均台距减小１倍,台风密度增加至４倍,但台网监测能力仅提高０．３￣０．４级,为使监测能力提高１级,平均台距需减至１／８,台网密度则增大６４倍,若台站短周期仪器放大率一律为５万倍,每万平方公里１个台的平均台网密度,其台网可监测最小震级为ＭＬ２．０（ｍｌｇ标度）。     

自动检测地震事件筛选方法研究

重点介绍禁核试北京国家数据中心研究的自动检测地震事件筛选方法.通过分析自动检测事件关联台站分布的合理性、关联台站的类型、关联信号参数的可靠性、多频带平均能量比等方法,判断自动检测事件的真伪.以国际数据中心审核公报事件为参考,研究的筛选方法可有效筛除43％自动检测虚假事件,使得自动检测误检率降低13％,并保持较低的误筛选率.此筛选方法可对国际数据中心以及禁核试北京国家数据中心不同处理平台的自动检测事件进行筛选分析.     

Spectral characteristics of natural and artificial seismic events in the Lop Nor test site, China

Seismic discriminants based on the spectral seismogram and spectral magnitude techniques have been tested to discriminate between three events; a nuclear explosion which took place in Lop Nor, China with m _b 6.1 and two earthquakes from the closest area with m _b 5.5 and 5.3, respectively. The spectral seismogram of the three events shows that the frequency content of the nuclear explosion differs from that of the earthquakes where the P wave is richier in high frequency content in the nuclear explosion than the corresponding earthquakes. It is also observed that the energy decays more rapidly for the nuclear explosion than for the earthquakes. Furthermore, the spectral magnitudes reveal significant differences in the spectra between the nuclear explosion and the two earthquakes. The observed differences appear to be quite enough to provide a reliable discriminant. The estimated stress drop from the magnitude spectra indicates a higher stress drop of the nuclear explosion relative to the earthquakes of the same tectonic region.     

区域地震信息网络系统的分步实现

文中对区域地震信息网络系统的“九五”目标和现实之间的矛盾进行了分析。为了有效地利用资金,结合地震系统现状及发展趋势,提出了从易到难的分步实现方案,并介绍了辽宁省地震局的初步实验结果。     

江苏数字地震台网台站震级偏差的分析

利用江苏数字地震台网1999年1月1日-2008年12月31日3个以上子台记录到的约1 500条地震,以台网的平均震级为标准震级,详细分析了江苏数字台网子台的震级偏差原因,结果显示:①在震中距较小时(100 km),子台测定的震级偏小,在100 km△250 km范围内,震级偏差基本为零;②子台测定的震级偏差存在地域分布特征,随方位角显示趋势性变化,地区邻近的子台之间变化特征相近或相似;③江苏数字台网子台台基类型中松散沉积对震级影响最大,偏差均为正值,最大偏差约0.3级,灰岩类型的台基对震级测定影响最小,几乎为零。     

景洪电站水库诱发地震监测台网地震监测能力评估

基于近震震级公式,得出景洪电站水库诱发地震监测台网理论监测能力在坝区为M_L 0.5,在坝区周边,理论监测能力为M_L 0.7。基于G-R震级频度关系及Wiemer Wyss最小完整性震级估计方法求取景洪电站水库诱发地震监测台网实际监测能力,结果证明,其实际监测能力能够满足理论监测能力的要求。在0.5的理论监测区范围内,最小完整性震级为M_L 0.0,而在0.7的理论监测范围内,最小完整性震级为M_L 0.4。     

台湾地震观测系统的发展与现状

台湾地处环太平洋地震带,在欧亚板块与菲律宾海板块相互碰撞作用下,地震活动强烈。为加强对台湾地区地震活动的监测工作,深入了解台湾地区的地震活动特性,减轻地震灾害,经过十几年的不断整合与建设,台湾地区已拥有“实时地震观测网”、“实时强地动观测网”、“自由场强震观测网”、“全球卫星定位系统GPS观测网”和“宽频地震网”,以及“强震预警系统”和“强震速报系统”等多套地震观测处理系统。为促进海峡两岸地震学界的深入认识和了解,增进两岸交流与合作,本文对台湾地区地震观测系统发展和现状做了较为详细的介绍。     

皖南地区区域地震台网监测能力分析

介绍了皖南地区区域地震台网20个测震台站的基本情况。对20个台站的背景噪声数字化记录进行了计算和分析,得其背景噪声均方根RMS值、有效测量动态范围,分析了噪声水平并按照地噪声水平的规定对各台进行了台基噪声分类。结果表明,20个测震台站中有9个I类台址、9个Ⅱ类台址、2个Ⅲ类台址。同时,分析了皖南地区区域台网的最小监测能力,结果表明,皖南地区区域台网最小监测能力为M_L≥-0.1—0.6,台站监测能力基本满足皖南地区监测需求。