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利用安徽数字地震台网安庆台记录的地震波形资料,运行Matlap S波分裂程序,对2011年1月19日安徽安庆4.8级地震的余震序列开展S波分裂研究。结果表明,快S波偏振方向有两个优势取向,分别为N73°E和N94°E,初步判断为区域应力场导致的EDA裂隙系各向异性结果。其中快S波N73°E偏振方向与区域应力场的主压应力方向N74°E基本相同,而快S波N94°E偏振方向稍有偏差,可能是由于4.8级主震产生的应力扰动引起的。慢S波延迟时间在0.82～10.92范围内变化,平均为2.84,主震后,延迟时间明显下降,可能反映了震后应力的释放过程,而几次较大余震前则处于上升高值状态,可能反映了较大余震前的应力积累过程。 相似文献
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《地震》2017,(3)
利用新疆区域数字化观测资料,计算了2011—2015年新疆3次6级地震序列的视应力值,并对视应力和震级的关系进行了讨论。结果表明:(1)主震视应力值高于余震视应力值,余震视应力和震级有一定的正相关关系;(2)主震后稍短时间内,视应力均处于整个序列的高值阶段,且在高值阶段会有较强余震发生,这可能是受到震后应力调整的影响;(3)强余震前,会出现视应力高值现象,强余震发生后,后续视应力值恢复到低值水平。计算了2016年底阿克陶6.7级和呼图壁6.2级地震余震视应力,目前阿克陶6.7级地震余震视应力处于高值状态,呼图壁6.2级地震余震视应力处于低值状态,对比研究5次余震视应力的值,对阿克陶6.7级和呼图壁6.2级地震序列类型进行了判定并对后续余震做了预测。 相似文献
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使用区域固定台网数字地震记录资料,计算2013年4月20日四川芦山MS7.0地震余震序列的震源谱参数,通过纵、横波的拐角频率比值和纵、横波位移谱零频极限比值计算波速比。结果显示:1拐角频率比值得到的波速比平均值约为1.27,零频极限比值得到的波速比平均值约为1.67,零频极限比值得到的结果更接近泊松介质的波速比1.73;2两种方法得到的波速比变化趋势基本一致:在主震后均处于较低异常水平,最后一个MS5.4余震后,波速比回返升高;3零频极限比值得到的波速比异常形态较明显,在3个MS5.4余震前都呈现出"降低-回返"的过程,在回返之后发生最大余震;4在数据处理过程中,是否对介质做非弹性衰减校正对两种方法的结果影响不大;5单台波速比与多台波速比的变化趋势基本一致。 相似文献
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根据流动台网对九江-瑞昌地震序列的定位结果,采用单台波速比方法,计算各流动台的波速比变化,得出以下结果:①各台波速比存在一定幅度的变化,但变化形态不一致,这可能与震源区应力调整有关:九江台和武蛟台的波速比在2006年4月下中旬至6月中旬这段时间较明显处于低值区间,相应的主余震的M-T图显示余震活动在该段时间内强度和频度有较明显的增强.②沿以武蛟和狮子洞两台连线的NW走向的波速比最小,结合主-余震北西向较优势分布和震源机制解的其中一组NW向节面,推断北西向断裂可能是九江-瑞昌5.7级主震的发震构造. 相似文献
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采用互相关系数法, 计算了2011年安庆MS4.8地震的余震S波分裂参数。 结果表明, 余震序列的S波分裂现象明显, 快S波平均偏振方向在近NNW向, 与区域最大水平主压应力方向基本一致。 通过分析延迟时间随时间的变化趋势, 可以看出MS4.8地震后有明显的应力释放现象。 在几次较大余震前, 观测到延迟时间呈现增加的特征, 并且其中一次余震在发生之前的短时间内还出现延迟时间减小的现象, 这一现象符合震前应力长时间积累和短时间应力释放的结论, 时间延迟在强震前会出现下降具有重要的地震短临预测意义。 研究认为 S 波分裂参数可以反映区域应力场的动态变化信息, 可以为安徽南部地区应力场研究与地震预测提供有用的信息。 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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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 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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Prof. Dr. W. A. Heiskanen 《Pure and Applied Geophysics》1958,41(1):1-18
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. 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