太原基准地震台地磁背景噪声分析

太原基准地震台数字化地磁观测项目建成运行后,背景噪声水平较大,影响观测资料的使用.采取多种技术措施,认为地电阻率观测对地供电是地磁稳频干扰的主要成分,是地磁背景噪声的一项重要干扰因素.     

阳原台短极距深井地电阻率建设

阳原地震台短极距深井地电阻率观测系统建设为"冬奥会保障晋冀蒙监测能力提升项目"河北分项.目前本项目已经完成全部土建工程,根据阳原地震台井深井地电阻率装置的建设,总结了电极制作、电极安装、回填等过程中的技术要求和实施过程.检测数据和试运行期间观测数据表明,阳原地震台短极距深井地电阻率建设符合电磁学科观测技术要求.     

河北省及邻区数字电扰动干扰分析

通过对河北省及邻区数字电扰动观测资料进行分析和环境调查,发现主要干扰因素为供电或漏电干扰。如:昌黎地震台地电阻率整点测量受到供电干扰,三河地震台受到恒远自动化仪表厂工作时段供电干扰,高碑店地震台受到商场大型设备供电干扰,广平地震台受到UPS交流电源漏电干扰,昌平地震台受到地铁运行漏电干扰等。电扰动干扰形态相似,均为超过本底值几倍、数十倍乃至上百倍的高值脉冲变化。     

大同地震台

大同中心地震台为国家基本台,组建于1988年4月。下辖大同地震台、测震中心、维护中心和灵丘地震台,担负着山西北部及晋冀蒙三省交界区的地震监测预报任务。大同地震台2004年以来经过台站观测环境优化改造及“十五”项目数字化改造,基本建成了“规模适中、功能齐全、设施先进、环境优美”的现代化地震台站。现有定点水准、地电阻率、地电场、地磁、钻孔应变、井下竖直摆倾斜仪、气象三要素等数字化前兆观测项目,具有较强的数字化地震前兆监测能力。     

新型地电阻率交流观测系统研究及江宁台观测试验

正地电阻率前兆观测是我国地震前兆观测重要手段之一,但是目前城市地铁和轻轨等对其造成了严重影响.利用低频交流电场与直流电场具有相似特性的特点(桂燮泰等,1988;马希融,1989),采用交流方法进行地电阻率观测,能够在一定程度上抑制地铁和轻轨的干扰影响(张宇等,2014;马小溪等,2015).目前,地电阻率台站所受到的突出干扰是地铁、轻轨等运行引起的近直流干扰,干扰周期主要为     

地电阻率多极距观测系统及试验研究

目前, 我国用于地震前兆监测的地电阻率观测系统大部分都是单一极距的, 这种观测方法在实际观测中普遍存在着地电阻率季节性变化的现象, 这种季节性变化与地震异常变化一起叠加在观测值中, 给地震异常的识别和判定带来了一定困难。 而解决这一问题的有效途径就是进行地电阻率的多极距观测。 本文介绍了采用ZD8MI电阻率多极距观测系统在山丹地震台的试验观测情况, 该系统是最新研制的、 专用于地震前兆监测的地电阻率多极距观测系统。 一年多的台站试验观测和反演结果表明, 浅层电阻率的变化相对较大, 而深层的相对变化较小, 因此利用多极距观测系统进行不同层位的地电阻率观测, 对排除干扰和识别地震前兆信息显得尤为重要, 是地电阻率观测技术发展的一个趋势。     

我国地震预报工作居世界先进行列

漫步展厅,一座全国地震监测台分布模型展现面前,星罗棋布的彩灯闪闪发光,向观众展示了我国地震监测预报工作取得的成就.解放前,我国只有4名地震工作者,在北京西山鹫峰观测地震活动.今天,全国已拥有一万多名地震工作,约等于世界各国从事地震工作人数的总和.20年来,我国已建立起460个地震监测台站,包括测震、水化学、水动态、地电等多种观测项目;同时,每年还开展2万多公里的地形变、地磁、重力等流动观测,观测点达4000个.全国还建成163个地方地震台和131个企业地震台,人数逾千;此外,我国开展的群众性观测活动受到了瞩目.我国在446个地、市、县设有地     

山西临汾地震台地电阻率异常分析与探讨

对山西临汾地震台地电阻率观测数据在临汾及其周边地区发生4．0级以上地震时的异常变化、异常形态进行了对比分析,认为,临汾中心地震台地电阻率对于捕捉该区地震前兆异常信息有积极的意义;对2008年4月以来临汾中心地震台地电阻率观测数据的变化情况、变化形态做了分析,其结果可为场源外区域地电异常的研究提供依据和参考。     

沈北新区地震台观测地质环境评价与地电阻率异常应急处置

地电阻率观测值受多种因素影响,它不仅与测量设备本身性能有关,还与观测场地的地质构造、地形地貌、岩性条件、水文地质和气象条件变化等有关,一旦这些因素发生变化,都会引起地电阻率测值发生改变.如何快速、准确、科学地识别以上致变因素,从中提取地电阻率地震前兆异常信息是及时科学处置异常的关键所在.本文以沈北新区地震台为例,探索性地进行了地震台观测地质环境评价,并以2020年地电阻率异常变化为例,初步分析了地电阻率异常影响因素,以期为深井地电阻率异常分析与处置提供参考与探讨.     

ZD8BI地电仪在南京(高淳观测基地)的观测与应用

南京地震台地电阻率观测因南京地铁的建设和运行受到干扰,故在距南京100km左右的高淳重新选址建设,现已投入正式观测.观测系统由ZD8BI地电仪、ZD8T装置稳定性检测仪、WL6B稳流电源,以及相关的输出设备和标定附件组成.在使用过程中发现,该观测系统优势突出,可实现网络远程控制,但某些细节可作进一步完善.本文就一年多来使用该观测系统的一些感受和想法,与地电观测同仁做一交流.     

Contribution to the knowledge of the magmatic evolution by the study of the variation of the coefficient of viscosity

The determination of the coefficient of viscosity of eruptive products gives useful elements to the knowledge of possible variations of composition and physical conditions of the magmas.     

Pictorial Series of the Manifestations of the Dynamics of the Earth

Studia Geophysica et Geodaetica -     

Magnetic stratigraphy of the Ordovician in the lower reach of the Kotuy River: the age of the Bysy-Yuryakh stratum and the rate of geomagnetic reversals on the eve of the superchron

Until recently, the existing data prevented the geophysicists from accurately dating the Bysy-Yuryakh stratum, which outcrops in the middle reach of the Kotuy River, constraining the time of its formation to a wide interval from the end of the Late Cambrian to the beginning of the Silurian. The obtained paleomagnetic data unambiguously correlate the Bysy-Yuryakh stratum to the Nyaian regional stage and constrain its formation, at least a considerable part of it, by the Tremadocian. This result perfectly agrees with the data on the Bysy-Yuryakh conodonts studied in this work and yields a spectacular example of the successful application of paleomagnetic studies in solving important tasks of stratigraphy and, correspondingly, petroleum geology. Within the Bysy-Yuryakh stratum, we revealed a large normal-polarity interval corresponding to the long (>1 Ma) period when the geomagnetic reversals were absent. This result, in combination with the data for the Tremadocian and Middle–Upper Cambrian sequences of the other regions, indicates that (1) the rate of occurrence of the geomagnetic reversals on the eve of the Ordovician Moyero superchron of reversed polarity was at most one reversal per Ma; (2) the superchron does not switch on instantaneously but is preceded by a certain gradual change in the operation conditions of the dynamo mechanism which, inter alia, manifests itself by the reduction of the frequency of geomagnetic reversals with the approach of the superchron. This finding supports the views according to which a process preparing the establishment of the superchrons takes place at the core–mantle boundary.     

Evolution of the Source of the Active Region of the Sun

Geomagnetism and Aeronomy - The magnetic evolution of the active region of the Sun at the level of the photosphere has been studied. Magnetic synoptic maps of the 2007 Kitt Peak Observatory were...     

On the solution of the reverse problem of geodesics with the help of the chord

Резюме Дается вывод формул для вычислений длины хорды, длины и азимутов нормаляных сечений и длины геодезической линии эллипсоида. Применяются тригонометрические функции данных величин и постоянные принятого ргфгргнц-эллипсоида, что является целесообразным при использовании вычислителQjных машин, особенно автоматов. Рабочие формулы рекомендуются в форме (8–11).

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Dedicated to Professor František Fiala on His 85th Birthday

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Address: Veveři 95, Brno.     

On the gravimetric undulations of the geoid and the deflections of the vertical

Summary The author mentions the aims of the World-wide gravity project he established in the Ohio State University in Columbus, in 1950. He outlines the practical procedure of the gravimetric computations of the undulationsN and the vertical deflection components and and emphasizes that only by the global international cooperation and additional gravity observations at sea carried out during the last decade it has been possible to gather to Columbus the needed gravity material. Since there exist still large gravimetrically unsurveyed areas it is of vital significance to study what gravity anomalies are best to be used for these regions. The given figures concerning the accuracy of theN, and , estimated theoretically and obtained in practice, indicate that in the gravimetrically well surveyed parts of the world like in Europe and the United States we can get gravimetrically on basis of existing gravity material theN-values with accuracy of about 5–10 meters, and and with the accuracy of about 1. The geoid undulationsN are already computed in Columbus for more than 6000 points of the northern hemisphere. The sample maps show the interesting geoid of Europe and vicinity between the latitudes 60° and 30° and longitude 5° W and 30° E, drafted on basis of more than 1000N-values computed at the corners of 1°×1° squares. It is interesting to realize that the geoid undulations in all this area are positive, the extreme values being between 40 and 50 meters. The geophysical significance of the geoid maps of this kind is pointed out.     

The effect of the pollution of the ground layer of the atmosphere on the albedo

Summary A simple model is proposed suitable for studying the effect of the ground layer of the atmosphere, polluted by aerosol, on the albedo. This model is founded on solving the equation of transfer of radiative energy. The numerical results are discussed, particular attention being paid to the analysis of errors due to neglecting the multiple reflection of solar radiation on the aerosol particles. A method which would also include the multiple reflection is proposed, and the conditions under which the presence of the aerosol is responsible for an increase or decrease of the solar radiation balance on the Earth's surface, are analysed.     

On the maintenance of the axisymmetric part of the flow in the atmosphere

Summary The maintenance of the axisymmetric component of the flow in the atmosphere is investigated by means of a steady-state, quasi-geostrophic formulation of the meteorological equations. It is shown that the meridional variations in the time-averaged axisymmetric variables can be expressed as the sum of three contributions, one being due to the eddy heat transport, another to the eddy momentum transport, and a third to the convective-radiative equilibrium temperature which enters the problem through the specification of a Newtonian form of diabatic heating. The contributions by the large scale eddies are evaluated through the use of observed values for the eddy heat and momentum transports.The contributions from each of the three forcing mechanisms to the temperature and zonal wind fields are invstigated individually and found to be of about equal importance. The sum of the three contributions are also presented for the temperature, the zonal wind, the stream function associated with the mean meridional circulation and the corresponding vertical motion. Although the results fail to reproduce the main observed features of the lower stratosphere, they are found to be in good agreement with observations in the middle latitude troposphere. At any pressure level, for example, the computed mean zonal wind has a jet-like profile and the axis of the jet is found to slope to the south with height, as observed in the atmosphere.Based in part on a thesis submitted by the first author as partial fulfillment of the requirements for the Ph.D. degree at the University of Michigan. — Publication No. 194 from the Department of Meteorology and Oceanography, The University of Michigan.     

On the determination of the non-linearity of the gravimeter scale

Summary The results of two different methods of the determination of the non-linearity of the gravimeter scale are compared; the economy is discussed as well.