关于自然电位日变形态与临震前兆的关系的初步研究

1、前言自然电位Vsp作为地电台站的正式观测项目,一直与地电阻率同时观测。尽管各地电台都积累了大量的自然电位资料,但对这些资料作认真地分析研究却很少。这不仅由于自然电位的复杂多变,也与人工观测的时间间隔及数据处理不当有关。     

山西数字化地电场仪观测系统干扰分析

对山西省5个地电台站的大地电场观测资料进行分析整理,对影响数字化地电场仪观测的观测系统干扰因素加以识别和分析,以期为地电场仪观测中干扰因素的有效排除及观测系统日常维护提供参考,有助于提高前兆资料的使用价值。     

河源地电台全空间地电阻率试验

河源地电台开展的深孔短极距试验观测，其电极深度达６５ｍ左右，μ值（Ｈ／Ｌ）达２．４。这种近似全空间的地电阻率观测方法，经试验证明在降低地电台站地表环境干扰因素的影响，提高观测精度，降低线路造价和维护费用等诸方面的效果是明显的．     

河北地电场台站观测干扰分析

通过对河北省4个地电场台站的观测资料全面分析判断,总结地电场干扰变化的可能因素;对"十五"新建的两个地电台站受到的干扰做出分析、判断;并结合台站实际观测环境,解决干扰源,对提高观测资料质量有一定的意义.     

榆树地震台地电比对观测分析

在介绍榆树地震台地电台站概况的基础上,利用比对观测数据,对地电观测中遇到的场地干扰、降雨干扰、雷电干扰等进行分析,结果表明:在相同条件下,同台比对观测更有利于地电观测中干扰的判定、识别。     

龙门石窟地下金属管道对地电观测的影响及解决方法

分析龙门石窟地下金属管道对地电观测的影响,通过对金属管道多种方法处理后,使之恢复地电原始观测环境,为地电台站遇到此类干扰提供参考.     

地电台地埋线缆高阻漏电点的简易定位装置

为定位地电台站地埋线缆高阻漏电点位置,根据差分电位法的原理,结合地电台站实际观测情况,设计一种由兆欧表和万用表结合使用的简易装置。根据理论计算和浚县地电场地的实地检验,证明在地埋线缆对地绝缘小于300 kΩ的情况下,使用该方法可以较准确快速地定位地埋线缆漏电点,位置误差在1 m以内。此方法利用一般地电台站监测设备,操作方便、简单,具备推广到受地埋线缆高阻漏电困扰的地电台站的条件。     

河北昌黎地震台地电场观测数据干扰排查与分析

地震台站地电场观测会受到各种因素的干扰,必须快速发现并消除干扰源,以保障观测数据的正常输出。2019年5月17日—6月4日,昌黎地震台地电场观测受不明原因干扰,观测数据产生畸变,与已知干扰类型数据特征进行对比分析,发现与常见干扰源所致数据变化形态特征不同;按照干扰数据变化特征,假设干扰源与观测台站的相对位置关系,布设简易的野外观测点,成功定位本次观测干扰源。最终确认,昌黎台地电场干扰由位于台站东南方向的铁件铸造厂变压器电缆漏电所致。此次干扰源排查,可为同类地电台站观测数据干扰分析提供参考。     

安徽省地电监测能力综合评价

以影响地电观测质量的主要因素及映震能力作为地电台站监测能力的主要评价指标,对安徽省5个地电台站的监测能力进行了综合评价,得到了安徽省地电前兆的基本情况,为安徽省未来的地电台站建设奠定了基础.     

最佳地电台台址条件与环境条件的讨论

地电台观测地电阻率及其变化以研究地震活动规律，首要的问题是如何选择或评估其台址的优劣，选取最佳地电台台址。文中讨论了地电台台址的地质构造条件、测区地下介质结构条件、介质水文条件、地形地貌条件、电磁干扰等对地电台站观测效能的影响，为选建和评估地电台台址提供较全面、系统的依据。     

VP宽频带倾斜仪现场自动校准装置设计

为了对VP宽频带倾斜仪进行现场校准,设计了一款基于单片机AT89C51的新型现场自动校准装置。经验证该装置在+8V激励电压情况下与高精度激光干涉仪结合使用,其校准相对误差为0.36%,满足小于1%的校准相对误差要求。     

大气重力波产生的大尺度赤道电离层扰动

本文研究了大气重力波产生的大尺度赤道电离层扰动的性质．当重力波的传播方向与磁场方向倾斜相交时,重力波在Ｆ区产生行进电离层扰动．当重力波垂直于磁场传播时,能触发等离子体Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性,形成大尺度赤道扩展Ｆ不均匀体．重力波引起的扩展Ｆ主要出现于晚上,行进电离层扰动则可能出现于任何时间．本文建立了行进电离层扰动和大尺度赤道扩展Ｆ的统一理论模型,深入全面地揭示了电离层扰动的性质．     

大气重力波产生的大尺度赤道电离层扰动

本文研究了大气重力波产生的大尺度赤道电离层扰动的性质．当重力波的传播方向与磁场方向倾斜相交时，重力波在Ｆ区产生行进电离层扰动．当重力波垂直于磁场传播时，能触发等离子体Ｒａｙｌｅｉｇｈ－Ｔａｙｌｏｒ不稳定性，形成大尺度赤道扩展Ｆ不均匀体．重力波引起的扩展Ｆ主要出现于晚上，行进电离层扰动则可能出现于任何时间．本文建立了行进电离层扰动和大尺度赤道扩展Ｆ的统一理论模型，深入全面地揭示了电离层扰动的性质．     

A Study of the Adaptive Method for Decoupling Overlapping Seismic Records

Signal extraction from overlapping seismic records is a common problem in geophysical data analysis. Identification and separation of multiple seismic arrivals, analysis of large earthquakes as multiple point sources, and calculation of the true yield of a large nuclear explosion from interfering small explosion, all hinge on our ability to effectively decouple two interfering wave signals. This paper presents a method for signal separation based on an adaptive filtering technique. We apply a semi-deconvolution algorithm to overlapping explosion records and S/SKS phase groups, and then perform noise reduction and signal decoupling under different a priori conditions and assess the stabilities using a variance reduction approach. We demonstrate, through numerical experiments and analysis of seismic station records, that the adaptive method can be both robust and practical for regional and teleseismic applications.     

The Optimal Spacing of Interfering Wells: An Analytic Solution

An exact expression is derived for the optimal spacing between interfering wells in a rectangular well field in an ideal confined aquifer. A simple, practical method for determining the optimal spacing is presented. The optimal spacing is shown to be substantially different from the spacing determined by use of the Theis formulation. The economic savings resulting from use of the revised approach are evaluated and found to be considerable, especially when the number of wells is large and the transmissivity of the aquifer low.     

HORIZONTALLY STRATIFIED MEDIUM AS A REFERENCE LARGE SCALE SYSTEM*

The geophysical system of horizontal layers may be considered as a large scale system. A large class of systems is identified which are equivalent to the geophysical processes in horizontal layering. The property of hierarchical aggregation of layers forms a convenient framework within which the peculiarities of such systems can be studied. Geophysical processes in multilayered media may serve as a reference physical model for a specified class of large scale systems, in order to take advantage and to apply geophysical methods of data processing, system analysis, and parameter identification. Specified large scale systems are decomposable, like geophysical systems, by use of recursive schemes. A category particulary susceptible to such a decomposition is any polynomial which is stable inside the unit circle. Sophisticated geophysical concepts, such as anisotropy, equivalence, and disappearance, can be used to approximate or to simplify the system by vanishing or adjusting the decomposition coefficients.     

Basin‐scale stream‐flow forecasting using the information of large‐scale atmospheric circulation phenomena

It is well recognized that the time series of hydrologic variables, such as rainfall and streamflow are significantly influenced by various large‐scale atmospheric circulation patterns. The influence of El Niño‐southern oscillation (ENSO) on hydrologic variables, through hydroclimatic teleconnection, is recognized throughout the world. Indian summer monsoon rainfall (ISMR) has been proved to be significantly influenced by ENSO. Recently, it was established that the relationship between ISMR and ENSO is modulated by the influence of atmospheric circulation patterns over the Indian Ocean region. The influences of Indian Ocean dipole (IOD) mode and equatorial Indian Ocean oscillation (EQUINOO) on ISMR have been established in recent research. Thus, for the Indian subcontinent, hydrologic time series are significantly influenced by ENSO along with EQUINOO. Though the influence of these large‐scale atmospheric circulations on large‐scale rainfall patterns was investigated, their influence on basin‐scale stream‐flow is yet to be investigated. In this paper, information of ENSO from the tropical Pacific Ocean and EQUINOO from the tropical Indian Ocean is used in terms of their corresponding indices for stream‐flow forecasting of the Mahanadi River in the state of Orissa, India. To model the complex non‐linear relationship between basin‐scale stream‐flow and such large‐scale atmospheric circulation information, artificial neural network (ANN) methodology has been opted for the present study. Efficient optimization of ANN architecture is obtained by using an evolutionary optimizer based on a genetic algorithm. This study proves that use of such large‐scale atmospheric circulation information potentially improves the performance of monthly basin‐scale stream‐flow prediction which, in turn, helps in better management of water resources. Copyright © 2007 John Wiley & Sons, Ltd.     

1987年9月23日日环食的电离层波动现象

本文给出了利用高频天波返回散射雷达对1987年9月23日日环食电离层效应的观测结果.分析表明,日食期间在日环食带电离层存在明显的不均匀结构和小尺度的波动,而日食过后在见食电离层区域出现大尺度的波动现象.     

1987年9月23日日环食的电离层波动现象

本文给出了利用高频天波返回散射雷达对1987年9月23日日环食电离层效应的观测结果.分析表明,日食期间在日环食带电离层存在明显的不均匀结构和小尺度的波动,而日食过后在见食电离层区域出现大尺度的波动现象.     

1987年9月23日日环食的电离层波动现象

本文给出了利用高频天波返回散射雷达对1987年9月23日日环食电离层效应的观测结果.分析表明,日食期间在日环食带电离层存在明显的不均匀结构和小尺度的波动,而日食过后在见食电离层区域出现大尺度的波动现象.