Ground truth seismic events and location capability at Degelen mountain, Kazakhstan

We utilized nuclear explosions from the Degelen Mountain sub-region of the Semipalatinsk Test Site (STS), Kazakhstan, to assess seismic location capability directly. Excellent ground truth information for these events was either known or was estimated from maps of the Degelen Mountain adit complex. Origin times were refined for events for which absolute origin time information was unknown using catalog arrival times, our ground truth location estimates, and a time baseline provided by fixing known origin times during a joint hypocenter determination (JHD). Precise arrival time picks were determined using a waveform cross-correlation process applied to the available digital data. These data were used in a JHD analysis. We found that very accurate locations were possible when high precision, waveform cross-correlation arrival times were combined with JHD. Relocation with our full digital data set resulted in a mean mislocation of 2 km and a mean 95% confidence ellipse (CE) area of 6.6 km² (90% CE: 5.1 km²), however, only 5 of the 18 computed error ellipses actually covered the associated ground truth location estimate. To test a more realistic nuclear test monitoring scenario, we applied our JHD analysis to a set of seven events (one fixed) using data only from seismic stations within 40° epicentral distance. Relocation with these data resulted in a mean mislocation of 7.4 km, with four of the 95% error ellipses covering less than 570 km² (90% CE: 438 km²), and the other two covering 1730 and 8869 km² (90% CE: 1331 and 6822 km²). Location uncertainties calculated using JHD often underestimated the true error, but a circular region with a radius equal to the mislocation covered less than 1000 km² for all events having more than three observations.     

地下水潮汐现象的物理机制和统一数学方程

用新的分层承压含水层模式 ,不但考虑含水层的力学压缩性质 ,而且考虑含水层的渗流特性 ,并结合扰动信息源的频率特性 ,分别研究扰动源地球固体潮、大气潮和地表负荷潮对承压井水位和流量的影响机理 ,给出相应的偏微分方程。从方程的解释或数值解讨论扰动源与承压井含水层的力学压缩参数、渗流特性参数及与频率特性频数的关系 ,进而给出承压井水位和流量对地球固体潮、大气潮和地表负荷潮汐响应的统一数学方程及其潮汐响应函数 ,并揭示了上述几类潮汐扰动信息源对承压井水位和流量影响的物理机理     

基于GIS与ANN耦合技术的地裂缝灾情非线性模拟预测系统——以山西榆次地裂缝灾害为例

现代地裂缝在世界许多国家普遍存在 ,已成为当今世界范围内的主要地质灾害之一。本文在详尽分析了山西榆次地裂缝的各个致灾因子的基础上 ,利用GIS技术建立了地质学意义上的专题层 ;然后采用人工神经网络技术构建出了地裂缝灾害活动性的评价模型 ,并建立了地裂缝活动性的评价系统 ,对榆次地裂缝进行了灾害活动性评价 ,为榆次市城建和国土规划等部门的正确决策提供了重要的科学依据     

用于地震调查的航空红外遥感实时传输系统研究

该系统提供了航空红外遥感资料的袢时采集和传输，为及时开展地震野外调查工作提供了一个有力的手段。该系统由红外传感器系统、机载站图像和数据实时处理系统、机载站通信系统、转发站通信系统、地面站接收系统、地面站图像和数据实时处理系统组成。     

野外简易脱气装置简介

根据水力学原理结合水氡在实验室分析中水样鼓泡脱气的方法 ,进行了大量的野外试验 ,研制开发了野外简易脱气装置。通过几个月的试观测 ,脱气装置气流稳定 ,脱气效率高 ,完全可以满足自动化观测仪器对气量的需求。该装置解决了地下水化学在野外冷水泉无法进行气体观测的难题 ,而且制作简单、费用低廉 ,非常便于推广。     

山西地电中短期前兆异常识别方法浅析

用傅氏滑动法、动态距平法、速率法、均值法等对山西大同台、代县台、临汾台的地电异常进行了分析 ,对地电阻率异常的判定、预报方法效能进行了评价 ,对不同的台站 ,从正常的变化形态中找出了突出异常的有效方法 ,从中提取出因地壳应力变化引起的地震前兆异常 ,结果表明 ,5 .0级以上地震在Δ=15 0 km范围内有明显的中短期前兆异常     

山西大同——阳高5.6级地震离石台地倾斜异常特征分析

1999年 11月 1日 ,在山西大同—阳高一带发生了 Ms5 .6地震。山西离石地震台依据该台地倾斜观测出现的异常 ,震前对这次地震作了较好的短临地震预报 ,为了探讨单台地震预报的方法 ,在该次短临预报的基础上 ,进一步用差分法、滤波法、矢量法、形态分析法对观测资料作了进一步的处理 ,发现该台地倾斜震前异常反映较好 ,具有明显的阶段性特征。指出 ,这对山西的地震监测预报有重要的作用。     

地形变场与现代地壳垂直运动及地震活动关系初探(Ⅰ)——地形变场的计算方法和物理意义

地震与地壳形变有着密切的关系 ,但台站地倾斜资料空间连续性不好 .为此在场分析的基础上 ,利用逐步订正法将地倾斜观测资料内插到 1°× 1°的经纬度网格点 ,引入曲面总曲率的概念计算格点上的Gauss曲率 ,并推广到格点化的有限区域上得到表征曲面形态和变形强度的地表形变场 .结果表明 :该方法可以合理地弥补资料不连续的缺陷 ,并在地表形变场上捕捉到一些关键的地表形变特征 ,如地凸区、地凹区、鞍形场等 .为地震分析和预报中如何拓展和利用大范围时空信息提供了一种有益的思路 .     

Public environmental information: understanding requirements and patterns of likely public use

Public access to environmental information received much attention in the last decade. Recent developments promote access to this information through public telecommunication networks. This paper describes a Web-based survey that explored the requirements and needs of likely users of public environmental information systems for London: educated middle-class members of the public, with high interest in environmental issues and computer literacy. The survey demonstrated current information consumption patterns and the reasons to gather and use such information.     

Spatially irregular sedimentation in a small, morphologically complex lake: implications for paleoenvironmental studies

A sub-bottom acoustic survey of Devil Lake on the Canadian Shield in southern Ontario reveals three acoustic facies: (I) a moderately acoustically transparent, laminated sequence interpreted as a glacilacustrine deposit in glacial Lake Iroquois or a subsequent phase in water depths up to 200 m greater than at present, (II) a transitional more transparent, less layered facies interpreted as being deposited in a more distal glacial lake from erosion of sediment in the watershed exposed by the failure of the ice dam and lowering of the glacial lake before stabilization by the development of forests, and (III) an acoustically transparent facies with similar transmissivity to the water column, interpreted as Holocene gyttja. Each is spatially variable in extent and thickness in response to those processes. There is only a very weak relation between sediment thickness and the water depth in which it was deposited. Wave processes prevent deposition in water depths less than about 6 m and evidence of erosion to the greatest depths of the lake (>40 m) is pervasive. The data demonstrate the value of acoustic survey in assessing lacustrine processes and the history of lakes, and the significance of such documentation in planning a coring program and in interpreting the results.