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选取华北部分地区2016—2019年流动地磁矢量资料,分析2018年2月12日永清MW 4.3地震前后岩石圈磁场变化特征。结果表明,地震前岩石圈磁场变化异常特征显著,震后异常消失。在震前岩石圈磁场变化中,磁场的D、I、F、H、Z分量出现不同程度的异常特征,这些震前异常呈现出相同的、相似的变化趋势。在震前随着时间的不断累积,岩石圈磁场变化异常愈加显著,其中震前1.5年期各分量震磁异常显著。与震前相比,震后岩石圈磁场变化特征及趋势发生了较大改变。 相似文献
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本文利用2019年和2020年两期的全国流动地磁矢量数据,针对玛多MS7.4地震震中附近的岩石圈磁场空间分布,分析研究了岩石圈磁场各个分量的震前变化特征。结果表明,玛多MS7.4地震发生前,震中附近的岩石圈磁场分量均发生了不同程度的变化:震中位于各分量的弱变化区域和零变线附近;震中位于各分量的高梯度带和低梯度带之间。本文证实了地震发生前会引起岩石圈磁场变化这一现象,并总结了震前地磁分量的变化特征,为今后强地震（尤其是M≥7.0地震）的震磁关系研究提供了一个震例参考。 相似文献
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本文以九江—瑞昌Ms5.7级地震和汶川Ms8.0级地震为研究对象,根据两个震区地震后观测所得地磁场三分量数据和“2005.0中国地磁图”项目所积累的地磁场三分量数据,建立了两个震区的岩石圈磁场模型.通过对比分析两个震区岩石圈磁场总强度、磁偏角、磁倾角三个独立分量地震前后的时空变化特征,初步探讨地震与岩石圈磁场变化关系,寻找有效震磁变化信息.结果表明：（1）两次震中均位于岩石圈磁场的磁偏角和磁倾角零值线附近;（2）震后震中百公里范围内岩石圈磁场分量均出现了不同程度的异常变化;（3）震中附近岩石圈磁场出现了明显的与地震相关的变化,该变化在两个震区表现出相近的规律性. 相似文献
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《地震研究》2021,44(4)
基于四川长宁地区平均点距为2 km的952个地磁总强度测量数据,经过日变化改正、主磁场剥离以及曲面样条插值等数据处理,得到长宁背斜附近地区的岩石圈磁场分布。结果表明:岩石圈磁场总强度范围为-400～200 nT,中值约为-4.4 nT,90%的数据位于(-4.4±32)nT。长宁背斜内部对应岩石圈正值区域,背斜边界对应负值区。边界区域内最显著的负值区域位于长宁背斜的西北端,背斜东北侧以正值区域为主,背斜南侧以负值区域为主。罗场向斜与建武向斜之间的高地震活动区域对应岩石圈磁场的正值区域。岩石圈磁场空间分布说明长宁背斜东、西部之间存在岩石圈磁场的局部负值嵌入体,该嵌入体或许造成了背斜东、西两部分的地震活动性的差异,背斜东、西部的岩石圈磁场梯度呈现西高东低的差异性分布。 相似文献
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基于青海及甘肃部分地区2020—2021年2期流动地磁测点的观测资料,获得该地区的岩石圈磁场异常变化,通过研究岩石圈磁场各个分量的变化特征,系统分析2022年1月8日青海门源6.9级地震前岩石圈磁场的异常变化特征。结果表明：(1)门源地震前,震中区域岩石圈磁场各个分量具有较为明显的异常显示。具体表现为：震中区域附近岩石圈磁场变化的水平矢量具有方向转向及幅值弱化的异常变化现象;垂直矢量方向出现明显的南向、北向对冲的异常现象;磁偏角在震中附近具有“0”变线和高梯级带分布;总强度和垂直分量在震中附近具有“0”变线分布,并发生弯曲。(2)依据压磁效应分析,冷龙岭断裂北部岩石圈磁场增大,应力变化主要以释放为主,应力变化应处于较低水平;冷龙岭断裂南部岩石圈磁场强度减小,应力变化主要以积累为主,应力变化应处于较高水平。门源地震前,冷龙岭断裂构造应力调整引起的压磁效应可能是造成震中区域岩石圈磁场异常变化的主要原因。 相似文献
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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. 相似文献
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Studia Geophysica et Geodaetica - 相似文献
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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... 相似文献
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V. E. Pavlov T. Yu. Tolmacheva R. V. Veselovskiy A. V. Latyshev A. M. Fetisova I. V. Bigun 《Izvestiya Physics of the Solid Earth》2017,53(5):702-713
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. 相似文献
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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. 相似文献
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Josef Vykutil 《Studia Geophysica et Geodaetica》1968,12(2):217-220
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).
Dedicated to Professor František Fiala on His 85th Birthday
Address: Veveři 95, Brno. 相似文献
Dedicated to Professor František Fiala on His 85th Birthday
Address: Veveři 95, Brno. 相似文献
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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. 相似文献
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Ivanka Jakubcová Věra Marvanová Miloš Pick Antonín Novotný Reviewer Z. Šimon 《Studia Geophysica et Geodaetica》1982,26(2):193-196
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. 相似文献
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Atmospheric temperature and humidity fields as well as information on other meteorological parameters are nowadays retrieved from radiance measurements recorded by operational meteorological satellites. Up to now, the inversion procedures used only take into account crude information on the topography of the Earth’s surface. However, the applied radiative transfer codes have to consider the Earth’s surface as the lower boundary of the atmospheric model and, therefore, need a more precise mean elevation and a classification of the roughness of the Earth’s surface. The influence of the topography of the Earth surface on retrieved temperature profiles is studied by using a physico-statistical inversion method. An objective analysis is made of the more precise mean elevation and derivation of roughness parameters using a new high-resolution digital elevation model (DEM) with a resolution of 500 m×500 m. By means of a geomorphological process and a newly developed topography rejection test, areas with a high surface roughness are localized and singled out. The influence of topography on the retrieved temperature profiles is illustrated by case studies. Changes are found predominantly in areas with a high variation of topography. Using the new high-resolution DEM and the topography rejection test, the geographical position of the calculated temperature profiles tends to be shifted towards areas with a small vertical variation of topography. The mean elevation determined by the new elevation model better characterizes the area observed. Hence, the temperature profiles can be calculated down to lower atmospheric levels. Furthermore, a guess profile better describing the atmospheric situation is selected by the more precise elevation. In addition, the temperature profiles obtained near the coast are improved considerably by the more precise determination of the surface property ‘sea’ and ‘land,’ respectively. Integration of an independent physical information such as topography leads, on average, to a slight improvement of the results of the physico-statistical inversion procedure. In some cases, however, significant improvements have been achieved regarding the desired accuracy of temperature profiles of the order of 1 K. In future, the spatial resolution of new high-resolution sounding instrumentation on the next generation of operational meteorological satellites will be increased. To exploit the resolving power of this new instrumentation, the different variation of the topography of the Earth surface, especially in regions with a high variation of topography, can be taken into account more precisely by using a high-resolution DEM. 相似文献