福建台网接入台湾台站对定位台湾中深源地震精度影响分析

福建台网负责监测中国台湾地区地震。对于中深源地震使用何种定位方法能获得较好的地震参数,这直接影响到地震定位精度。利用JOPENS系统中交互分析软件MSDP提供的定位方法,对同一地震进行两次定位,即不使用和使用接入的台湾台站,将福建台网得出的两次结果与中国台湾公布的地震参数进行对比,分析定位精度,进而找出适用于台湾地区中深源地震的定位方法,以便进一步判断在地震速报中使用这些台站进行辅助定位的可行性,并给出相关的操作方法及建议。     

地震预警定位方法研究

实时地震定位是地震预警系统中必须解决的关键问题之一.文中在借鉴已有实时地震定位方法的基础上并结合我国台网的实际情况,推导得到一套利用前三/四台P波、S波到时信息进行实时定位的算法.作者选取2000年至2008年问福建省地震监测台网记录到的68个3.0级以上地震对该算法进行验证.研究结果表明,采用文中方法的定位结果具有一...     

福建地震台网对中国台湾中深源地震定位方法探究

利用 JOPENS 系统中交互分析软件 MSDP 提供的定位方法,对中国台湾中深源地震进行定位,分析福建地震台网结果与中国台湾公布的地震参数的吻合性,进而判断合适的定位方法。     

地震预警连续定位方法研究

本文首先总结了地震预警系统中采用的一些实时定位方法,随后结合我国地震监测台网实际运行情况,提出了一套从单个台站触发开始逐渐过渡到利用前四台触发信息的完整地震预警连续定位方法.利用福建省地震监测台网记录的68个M3.0级以上地震观测记录,对本文方法的验证结果表明,对于网内地震,采用本文方法的单台定位结果误差均小于为50 km,双台定位结果误差均小于35 km,三台定位结果误差约为15 km,四台定位结果误差约为6 km;网外地震的三台、四台定位结果误差均小于30 km.推导了采用本文三、四台预警定位方法的误差公式.利用福建地区现有及"十一五"完成后的地震观测台网分别计算得到了定位误差分布图.根据误差分析结果即可对定位结果的可靠性预先做出判断,有利于提高地震预警系统运行的可靠性.     

福建地震台网地震速报中对台湾地震台站辅助定位方法应用研究

利用福建地震台网接入的台湾地震观测台站,结合福建的部分台站,定位台湾地区地震,分析测定结果与台湾公布的地震参数吻合性。并对用此方法分析地震的时间作大致计算,进而判断在地震速报中使用这些台站进行辅助定位的可行性,给出相关的操作方法及建议。     

中国东北深源地震定位方法解析

黑龙江省有时会发生震源深度300-600 km的深源地震,且地震释放能量及有感范围均较大。该地区发生M > 6.0深源地震会产生较大社会影响,对于深源地震,快速准确地确定震源参数具有重要意义。利用黑龙江省测震台网自"十五"项目投入运行以来记录的31条深源地震数据,采用LocSAT和HypoSAT定位方法进行重新定位,将定位结果与中国地震台网中心统一编目给出的目录数据进行对比,寻求更加适用该区深震的定位方法。分析表明,对于黑龙江省测震台网记录的东北地区深源地震,使用HypoSAT方法进行定位结果优于LocSAT定位方法。     

玉门5.9级地震序列定位研究

利用玉门5.9级地震震区临时台网和甘肃数字台网监测资料,用两种方法对地震序列进行了定位,并对结果的误差进行了分析.结果表明,利用"双差法"可以大大提高定位精度特别是震源深度的定位精度.     

不同地震定位方法确定震源深度对比分析

使用新疆地震台网地震观测资料,采用 MSDP 系统单纯型、Locsat、Hypo2000、hypoSAT 等4种定位软件和经典直观的中线法、石川法、交切法作图法及 BLOC86速度模型计算定位方法,对2010年1月18日19时35分呼图壁 ML 4．0地震分别定位。将各自确定的震源深度、震中参数进行对比分析,认为单纯型定位方法确定的震源深度太浅。     

地震定位研究及应用综述

地震定位是地震学中最经典、最基本的问题之一，提高定位精度也一直是地震学应用研究的重要课题之一。本文就目前各种地震定位方法进行了大体分类并概述了基本原理及其应用，介绍了目前在国内各实时地震观测系统中应用的台网定位方法，同时将部分台网方法应用于黑龙江省绥棱爆破的定位。     

JOPENS系统单纯型定位法定位中国台湾地震精度分析

利用JOPENS系统中交互分析软件MSDP提供的单纯型定位法,对中国台湾地震进行分析定位,将结果与中国台湾公布的参数进行对比;分析此定位方法得出的地震参数与中国台湾结果的吻合性,判断可否使用此定位方法,对中国台湾地震进行定位。     

双差地震定位法在邯郸-邢台地区地震精确定位中的初步应用

采用双差地震定位方法,利用2001-2006年间邯郸数字台网记录到的413次M1≥1.0地震的P波和S波震相到时资料,对邯郸一邢台地区(35.0°～38.0°N,113.0°～116.0°E)的地震进行了重新精确定位.经重新定位后得到其中295次地震的基本参数.重新定位结果显示了比较精细的震中分布图像和有所收敛的震源深度剖面图像,震源深度的优势分布为12～18 km,平均深度为14.9 km,部分震中位置与震源深度变化较大的地震向断裂带靠近.     

倾斜仪在地震定位中的应用

利用上海综合深井观测系统中两分向倾斜仪记录的25Hz采样观测数据,与相邻台站地震仪对东海MS7.0中源地震进行地震定位结果对比分析。结果显示发震时刻最大误差仅0.06s,震中位置最大误差5.1km,并且定位结果都保持了较小的定位残差。因此高采样率深井地倾斜仪记录的观测数据可以用于地震的定位分析。     

Improving Regional Seismic Event Location in China

—?In an effort to improve our ability to locate seismic events in China using only regional data, we have developed empirical propagation path corrections and applied such corrections using traditional location routines. Thus far, we have concentrated on corrections to observed P arrival times for crustal events using travel-time observations available from the USGS Earthquake Data Reports, the International Seismic Centre Bulletin, the preliminary International Data Center Reviewed Event Bulletin, and our own travel-time picks from regional data. Location ground truth for events used in this study ranges from 25?km for well-located teleseimic events, down to 2?km for nuclear explosions located using satellite imagery. We also use eight events for which depth is constrained using several waveform methods. We relocate events using the EvLoc algorithm from a region encompassing much of China (latitude 20°–55°N; longitude 65°–115°E). We observe that travel-time residuals exhibit a distance-dependent bias using IASPEI91 as our base model. To remedy this bias, we have developed a new 1-D model for China, which removes a significant portion of the distance bias. For individual stations having sufficient P-wave residual data, we produce a map of the regional travel-time residuals from all well-located teleseismic events. Residuals are used only if they are smaller than 10?s in absolute value and if the seismic event is located with accuracy better than 25?km. From the residual data, correction surfaces are constructed using modified Bayesian kriging. Modified Bayesian kriging offers us the advantage of providing well-behaved interpolants and their errors, but requires that we have adequate error estimates associated with the travel-time residuals from which they are constructed. For our P-wave residual error estimate, we use the sum of measurement and modeling errors, where measurement error is based on signal-to-noise ratios when available, and on the published catalog estimate otherwise. Our modeling error originates from the variance of travel-time residuals for our 1-D China model. We calculate propagation path correction surfaces for 74 stations in and around China, including six stations from the International Monitoring System. The statistical significance of each correction surface is evaluated using a cross-validation technique. We show relocation results for nuclear tests from the Balapan and Lop Nor test sites, and for earthquakes located using interferometric synthetic aperture radar. These examples show that the use of propagation path correction surfaces in regional relocations eliminates distance bias in the residual curves and significantly improves the accuracy and precision of seismic event locations.     

Effects of Location Errors in Pattern Informatics

The effect of location errors in the performance of seismicity-based forecasting methods was studied here using one particular binary forecast technique, the Pattern Informatics (PI) technique (Rundle et al., Proc Nat Acad Sci USA 99, 2514–2521, 2002; Tiampo et al., Pure Appl Geophys 159, 2429–2467, 2002). The Southern Californian dataset was used to generate a series of perturbed catalogs by adding different levels of noise to epicenter locations. The PI technique was applied to these perturbed datasets to perform retrospective forecasts that were evaluated by means of skill scores, commonly used in atmospheric sciences. These results were then compared to the effectiveness obtained from the original dataset. Isolated instances of decline of the PI performance were observed due to the nature of the skill scores themselves, but no clear trend of degradation was identified. Dependence on the total number of events in a catalog also was studied, with no systematic degradation in the performance of the PI for catalogs with events in the cases studied. These results suggest that the stability of the PI method is due to the invariance of the clustering patterns identified by the TM metric (Thirumalai and Mountain, Phys Rev A 39, 3563–3573, 1989) when applied to seismicity.     

基于CT胸部图像肺结核球的定位

随着医学图像处理的快速发展,病灶区定位在医学应用中越来越引起人们的关注。以CT图像为研究对象,针对肺结核球的定位问题,先对预处理过的CT图像利用阈值技术二值化,采用形态滤波去除小桥,然后将每个连通区域标记出来。最终通过包括面积、周长、位置参数及形状参数等特征的决策器来判断确定肺结核球区域,并且定位出病灶区位置。     

Differential Evolution Algorithm in the Earthquake Hypocenter Location

—?A novel global optimizing algorithm?—?Differential Evolution (DE)?—?has appeared recently. This method is easy and advantageous when used for kinematic location of the earthquake hypocenter. The motivation for implementing a robust (i.e., global and nonlinear) optimizing algorithm for the location problem is to obtain better results than those from the classical (i.e., linearized) approach (such as the FASTHYPO, HYPOELLIPSE, HYPOCENTER solutions, among others). Better solutions have lower final misfits expressed as the common L2 norm. The features of the DE algorithm are studied on a set of synthetic location problems. The DE procedure is controlled by 3 internal parameters, which are easy to adjust, and the convergence properties are very good. Location results using DE are compared with the HYPO71 solutions for real earthquake data from the Gulf of Corinth region, Greece. The DE results are significantly better. The DE optimizing algorithm seems to be very promising both for the location problem as well as for other problems in geophysics.     

地震定位研究综述

综述了各种地震定位方法的基本原理，重点介绍了Geiger的经典方法以及在此基础上建立的各种线性方法：联合定位法，相对定位法，和最新的双重残差法；对每一种方法的应用情况，尤其是国内的工作做了总结；同时也指出了各种方法的特点，并进行了相应的比较，此外，还简要介绍了空间域的定位方法和各种非线性定位方法。     

模拟退火算法在地震定位中的应用

阐述了模拟退火算法及其在地震定位中的原理,以震相观测到时与理论到时之差(到时残差)为目标函数,利用模拟退火算法求解目标函数的最小值以获得地震的震源参数。在模拟退火算法的地震定位中根据震相的可靠程度对不同震相设置了相应的定位权重;对震相的走时误差设置了3组不同的值,以分析走时误差对定位结果的影响,对随机生成的1000个模拟地震进行模拟退火算法再定位。结果表明,走时误差越小,定位结果越准确。最后,通过地震震例进一步验证了模拟退火算法在地震定位中的可用性。     

波形模板匹配定位方法在北京地区的应用

在地震学研究中，高效的微震检测方法是既重要又具有挑战性的问题。本文对波形模板匹配检测方法、匹配定位技术、波形自相关检测技术进行详细介绍和对比，对国内外应用实例进行总结，并展望微震检测方法应用前景和发展趋势。利用基于图形处理器加速的匹配定位技术和双差地震定位法，对北京地区19个台站记录的2015年连续地震资料进行分析。基于中国地震台网中心提供的地震目录，筛选出245个地震事件作为模板事件，检测得到1229个地震事件，约为地震台网原始地震目录数量的5倍。精定位结果可显示小震沿黄庄-高丽营断裂周边小断裂分布形态特征，本文微震检测和定位结果可为研究北京地区地震活动性与发震断层深部构造提供基础数据支撑。