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国际上新近发展的“基于概率的完整性震级”(PMC)方法,具有可考察地震定位中由于台站人为选择等造成的台网监测能力下降,以及避免传统基于G-R关系的统计算法因地震数目过少而无法评估等优点.本研究利用PMC方法,计算得到内蒙古区域地震台网39个台站对周边地震事件的检测概率及台网检测概率.单台检测概率结果显示:PMC方法能够客观地反映39个台站对地震事件的检测能力;因台网布局等影响,内蒙古区域地震台网中西部和中东部地区的台站检测能力较强,而靠近蒙古、俄罗斯边境的台站, 阿拉善右旗附近地区的台站,以及邻近吉林、黑龙江等地区的台站检测能力较低.合成检测概率结果显示,由于邻省台站的引入,全区80%的地区基于概率的最小完整性震级MP达到2.2左右,其余地区MP达到3.3左右.为提高地震台网监测能力,建议在监测能力较弱的中蒙交界地区、东北部地区,以及阿拉善左旗以西地区适度加密台站,进一步优化台网布局. 相似文献
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《地球物理学进展》2016,(5)
全面禁止核试验条约组织(The Comprehensive Nuclear-test-ban Treaty Orginization,CTBTO)筹委会临时技术秘书处(Provisional Technical Secretariat,PTS)国际数据中心(International Data Centre,IDC)负责对来自国际监测系统(International Monitoring System,IMS)台站数据的接收、处理、分析、报告及归档.降低在全球范围内的监测阈值,提高自动处理结果的准确性,是IDC一直以来所追求的目标.在核查地震监测方面,IDC不断改进数据处理软件以满足监测技术发展所带来的新需求,开展了软件结构优化、精确的地球物理模型应用,先进的数据处理方法集成等工作.本文首先简要介绍了IDC地震数据处理方法,然后从软件结构、信号检测与关联算法、区域走时模型等几个方面总结了目前IDC地震数据处理软件研究进展,对涉及的相关算法进行了分析.希望对国家数据中心数据处理软件的发展、以及对核查技术相关的研究工作起到借鉴作用. 相似文献
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在远程检测地下核爆炸的唯一途径是依据其产生的地震信号。正因为这个原因，为验证“全面禁止核试验”情况提供数据而建立的国际监测系统（IMS）还得包含地震台站网。然而，即使监测到了地下核爆信号，也不可能准确无误地辨别出来。该监测系统旨在提供可鉴别出明显是天然扰动的数据和可识别出极有可能是地下核试验的数据。如果检测到可疑扰动，禁止核试验条约的缔约国就可要求这个被怀疑进行核试验的国家允许国际调查组织进入震中区进行现场视察，来核实其是否确实进行了核试验。 相似文献
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地震事件检测能力在地震观测台站和地震临时观测点的运行中起着重要的作用.在确定网络几何结构下的地震监测台网中,地震监测能力是由监测到的地震事件震级的大小决定的.本文使用了一种完全基于测量噪声统计的SN-CAST方法计算了甘肃预警台网的地震监测能力空间分布,得到甘肃预警台网建立好后将平均监测能力提高到ML 0.8级,监测能力最高处可达到ML 0.2级,目前由44个固定性台站组成的甘肃地震监测台网监测能力为平均监测能力ML 1.7级,监测能力最高处为ML 0.5级,预警台网的建立对整个甘肃台网的监测能力将有较大幅度的提高,根据地震波走时特征分析了甘肃预警台网的空间预警发布时间估测结果,得到地震频发的甘东南和南北地震带地区地震预警时间所用时间较短,在5 s左右,而人口比例偏少地震发生概率偏小的河西走廊和肃北地区预警时间较长,最高为30 s左右,最终计算结果表明预警规划方案基本满足了地震预警设立要求. 相似文献
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传统基于数据融合的地震预警网络系统在对地震进行预警时,需要分析大量的地震数据,存在地震预警偏差高和动态监测性能差的弊端,因此本论述设计了基于云计算的地震预警网络系统,采用SaaS技术设计系统总体架构,通过核心是STM32F103RET6单片机的地震监测传感器模块,采集地震波信息。系统采用多地区地震数据并发过滤接收技术,对海量数据进行及时有效的接收和处理。系统实现过程中设计了系统的软件架构,基于Web页面的地震震波仿真显示模型,用浏览器中的High Chart JS软件模拟显示地震波形,给出了系统软件进行地震事件触发检测管理线程流程以及系统台站误触发判断实现流程。实验结果说明,所设计系统能够准确的对地震发生作出预警,动态监测性能强。 相似文献
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For the purpose of verifying compliance with the CTBT seismic monitoring is one of the four techniques used by the IDC. In order to improve the accuracy of the automatic and the reviewed bulletin epicenter locations the IDC uses SASC for the IMS seismic stations. SASC determination is a straightforward calculation done by comparing for selected events the azimuth and slowness from the waveform processing using array techniques to the theoretical values based on the event locations and the velocity model.The main problem, however, is to build a set of reference events, whose locations are accurate enough and not based on information from the stations to be calibrated. A reference event list assumed to meet this requirement is the Gamma bulletin, which was collected since 1993 and was compiled in the framework of the GSETT-3. In this work calculation of SASC for regional to teleseismic distances (up to 30 degrees) was performed for 11 IMS primary arrays. The calculation was done using Pg, Pn, P, Sg, Sn, and S phases based on the detection list obtained from the pIDC and the Gamma bulletin for 6 years (1993–1999). The number of Gamma events varies from several hundreds for some arrays (BRAR) to several tens of thousands for others (i.e. ARCES, ILAR). Due to the fact that the Gamma bulletin is purely voluntary, the coverage is non-uniform both in time and in space and the location accuracy is non-uniform. This drawback can be overcome by encouraging signatory states to submit quality Gamma bulletin data to the IDC. The work presented here can be used as a routine procedure for improving IMS array performance, especially at regional distances. 相似文献
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LIU Rui-feng CHEN Yun-tai Peter Bormann REN Xiao HOU Jian-min ZOU Li-ye YANG Hui 《地震学报(英文版)》2005,18(6)
By using orthogonal regression method, a systematic comparison is made between body wave magnitudes determined by Institute of Geophysics of China Earthquake Administration (IGCEA) and National Earthquake Information Center of US Geological Survey (USGS/NEIC) on the basis of observation data from China and US seismograph networks between 1983 and 2004. The result of orthogonal regression shows no systematic error between body wave magnitude mb determined by IGCEA and mb (NEIC). Provided that mb (NEIC) is taken as the benchmark, body wave magnitude determined by IGCEA is greater by 0.2～0.1 than the magnitude determined by NEIC for M=3.5～4.5 earthquakes; for M=5.0～5.5 earthquakes, there is no difference; and for M≥6.0 earthquakes, it is smaller by no more than 0.2. This is consistent with the result of comparison by IDC (International Data Center). 相似文献
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不同震相具有不同的振动特性和传播规律,对应各自不同的幅值-震中距-深度衰减规律,本文基于禁核试核查国际数据中心公报,统计P,PcP,PKP,PKPbc及PKPab远震和极远震震相样本随震中距的分布,运用基于残差统计的迭代方法回归上述震相的幅值-震级-震中距-深度模型,通过震级残差标准差与均值的统计进行模型评估,结果显示:P,PcP,PKP,PKPbc及PKPab震相的震级残差标准差范围为0.30—0.36,满足一般震相相容性判断的需求;除PKPbc的残差均值大于0.03外,其余震相残差均值均为0.01左右,模型的系统偏差极小,甚至可以忽略不计。最后针对模型进行了幅值预测比对、震级相容性检测、极远震体波震级计算等三个不同场景的应用研究,验证模型可用于日常地震监测。 相似文献
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D. N. Anderson H. J. Patton S. R. Taylor J. L. Bonner N. D. Selby 《Pure and Applied Geophysics》2014,171(3-5):537-547
The Comprehensive Nuclear-Test-Ban Treaty (CTBT), a global ban on nuclear explosions, is currently in a ratification phase. Under the CTBT, an International Monitoring System (IMS) of seismic, hydroacoustic, infrasonic and radionuclide sensors is operational, and the data from the IMS is analysed by the International Data Centre (IDC). The IDC provides CTBT signatories basic seismic event parameters and a screening analysis indicating whether an event exhibits explosion characteristics (for example, shallow depth). An important component of the screening analysis is a statistical test of the null hypothesis H 0: explosion characteristics using empirical measurements of seismic energy (magnitudes). The established magnitude used for event size is the body-wave magnitude (denoted m b) computed from the initial segment of a seismic waveform. IDC screening analysis is applied to events with m b greater than 3.5. The Rayleigh wave magnitude (denoted M S) is a measure of later arriving surface wave energy. Magnitudes are measurements of seismic energy that include adjustments (physical correction model) for path and distance effects between event and station. Relative to m b, earthquakes generally have a larger M S magnitude than explosions. This article proposes a hypothesis test (screening analysis) using M S and m b that expressly accounts for physical correction model inadequacy in the standard error of the test statistic. With this hypothesis test formulation, the 2009 Democratic Peoples Republic of Korea announced nuclear weapon test fails to reject the null hypothesis H 0: explosion characteristics. 相似文献
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利用2017年8月1日至2017年12月31日四川地震台网和甘肃地震台网记录到的发生在青藏高原东缘的731个地震事件的9 284条Pg震相到时数据,首先反演了该地区的“最小一维速度模型”,并将该模型和选取的速度模型建立对比模型,以九寨沟地震序列为研究目标,定量讨论了两种速度模型分别在绝对定位和相对定位方法中对定位结果的影响。所得定位结果表明:反演获得的“最小一维速度模型”在重定位中可以有效地减小地震走时均方根残差;绝对定位比相对定位更加依赖于一维速度模型,一维速度模型会直接影响绝对定位结果中的震源分布形态,但在相对定位结果中仅起到调整地震事件相对位置的作用;在地震绝对定位中,震级越大的地震对于速度模型越敏感,而这一特点在相对定位中表现得并不明显。通过本项研究可知,在地震定位研究中,联合采用绝对定位和相对定位方法是最佳策略。 相似文献
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Perspectives of Cross-Correlation in Seismic Monitoring at the International Data Centre 总被引：1，自引：0，他引：1
We demonstrate that several techniques based on waveform cross-correlation are able to significantly reduce the detection threshold of seismic sources worldwide and to improve the reliability of arrivals by a more accurate estimation of their defining parameters. A master event and the events it can find using waveform cross-correlation at array stations of the International Monitoring System (IMS) have to be close. For the purposes of the International Data Centre (IDC), one can use the spatial closeness of the master and slave events in order to construct a new automatic processing pipeline: all qualified arrivals detected using cross-correlation are associated with events matching the current IDC event definition criteria (EDC) in a local association procedure. Considering the repeating character of global seismicity, more than 90 % of events in the reviewed event bulletin (REB) can be built in this automatic processing. Due to the reduced detection threshold, waveform cross-correlation may increase the number of valid REB events by a factor of 1.5–2.0. Therefore, the new pipeline may produce a more comprehensive bulletin than the current pipeline—the goal of seismic monitoring. The analysts’ experience with the cross correlation event list (XSEL) shows that the workload of interactive processing might be reduced by a factor of two or even more. Since cross-correlation produces a comprehensive list of detections for a given master event, no additional arrivals from primary stations are expected to be associated with the XSEL events. The number of false alarms, relative to the number of events rejected from the standard event list 3 (SEL3) in the current interactive processing—can also be reduced by the use of several powerful filters. The principal filter is the difference between the arrival times of the master and newly built events at three or more primary stations, which should lie in a narrow range of a few seconds. In this study, one event at a distance of about 2,000 km from the main shock was formed by three stations, with the stations and both events on the same great circle. Such spurious events are rejected by checking consistency between detections at stations at different back azimuths from the source region. Two additional effective pre-filters are f–k analysis and F prob based on correlation traces instead of original waveforms. Overall, waveform cross-correlation is able to improve the REB completeness, to reduce the workload related to IDC interactive analysis, and to provide a precise tool for quality check for both arrivals and events. Some major improvements in automatic and interactive processing achieved by cross-correlation are illustrated using an aftershock sequence from a large continental earthquake. Exploring this sequence, we describe schematically the next steps for the development of a processing pipeline parallel to the existing IDC one in order to improve the quality of the REB together with the reduction of the magnitude threshold. 相似文献
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It is proposed that some possible macroseismic epicenters can be determined quickly from the relationship that the microseismic epicenters located by instruments bear with faults.Based on these so-called macroseismic epicenters,we can make fast seismic hazard estimation after a shock by use of the empirical distribution model of seismic intensity.In comparison with the method that uses the microseismic epicenters directly,this approach can increase the preccision of fast seismic hazard estimation.Statistical analysis of 133 main earthquakes in China was made.The result shows that the deviation distance between the microseismic epicenter and macroseismic epicenter falls within the range of 35km for 88% earthquakes of the total and within the range of 35to 75km for the remaining ones.Then,we can take the area that has the microseismic epicenter as its center and is 35km in radius as the area for emphatic analysis,and take the area within 75km around the microseismic epicenter as the area for general analysis.The relation between the 66 earthquake cases on the N-S Seismic Belt in China and the spatial distribution characteristics of faults and the results of focal mechanism solution were analyzed in detail.We know from the analysis that the error of instrumental epicenter determination is not the only factor that gives effects to the deviation of the macroseismic epicenter.In addiditon to it,the fault size,fault distribution,fault activity,fault intersection types,earthquake magnitude,etc,are also main affecting factors.By sorting out ,processing and analyzing these affecting factors,the principle and procedures for quickly determining the possible position of the macroseismic epicenter were set up.Taking these as a basis and establishing a nationwide database of faults that contains relevant factors,it is possible to apply this method in practical fast estimation of seismic hazard. 相似文献
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Statistical analysis of the ion density measured by the satellite DEMETER in relation with the seismic activity 
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下载免费PDF全文 Michel Parrot 《地震科学（英文版）》2011,24(6):513-521
This paper is related to study of the ion density recorded by the low altitude satellite DEMETER. It will present ionospheric perturbations observed during large seismic events. As the ionosphere is highly variable, the paper will show a statistical analysis performed on the plasma parameters during night time. An algorithm has been implemented to detect crests and troughs in the data before world-wide earthquakes. The earthquakes have been classified depending on their magnitude, depth, and location (land, below the sea, close to a coast). Due to the orbit, DEMETER returns above the same area every day (once during day time, once during night time) but not at the same distance of a given epicenter. Then, for each earthquake, data have been checked until 15 days before the shock when the distance between the trace of the orbit and the epicenter is less than 1 500 km. The results of the statistical analysis are presented as functions of various parameters. A comparison is done with two other databases where, on one hand, the location of the epicenters has been randomly modified, and on the other hand, the longitude of the epicenters has been shifted. Results show that the number and the intensity of the ionospheric perturbations are larger prior to earthquakes than prior to random events, and that the perturbations increase with the magnitude. 相似文献