Non-Plane Geometries of Seismic Surface Wavefields and Their Implications For Regional Surface-Wave Tomography     

Wolfgang Friederich  Erhard Wielandt  Stefan Stange 《Geophysical Journal International》1994,119(3):931-948

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油气地表化探指标的统计分类和优选     

李汉林  赵永军  查明 《地质论评》1994,40(7):39-45

本文研究了影响趋势面拟合度的主要因素，提出了由参与趋势分析的数据个数n、数据的标准偏差σ和所期望的拟合度c估计最佳趋势面次数k的统计方法。同时还给出了多化探指标下，综合选择趋势面次数的五、c图法。按上述方法，选择趋势面，对我国东部几个地区化探资料处理效果良好，这对于多指标，大数量化探异常的研究有一定的参考价值。  相似文献   

Determining palaeomagnetic poles and anomalous skewness from marine magnetic anomaly skewness data from a single plate     

Katerina E. Petronotis  Richard G. Gordon  Gary D. Acton 《Geophysical Journal International》1992,109(1):209-224

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Seismic yield determination of Soviet underground nuclear explosions at the Shagan River test site   总被引：4，自引：0，他引：4  

Frode Ringdal  Peter D. Marshall  Ralph W. Alewine 《Geophysical Journal International》1992,109(1):65-77

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The seafloor spreading rate dependence of the anomalous skewness of marine magnetic anomalies   总被引：1，自引：0，他引：1  

W. R. Roest  J. Arkani-Hamed  J. Verhoef 《Geophysical Journal International》1992,109(3):653-669

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北太平洋卫星测高大地水准面异常          下载免费PDF全文

许天铭 《地球物理学报》1987,30(3):318-322

自1973年以来,NASA已发射了三颗与卫星测高有关的卫星,测高标准误差≥±10cm。已求得全球平均海水面高度图标准误差≤±1m。它的短波成分比卫星重力大地水准面的丰富得多。由于引入卫星测高资料,已把地球重力位系数从原来的22×22阶次提高到现在的180×180阶次,估计在卫星测高加密观测地区,可提高到720×720阶次。现在,卫星测高已成为综合应用卫星SEASAT的主要观测项目之一,这对于研究海洋地球物理和全球性地球动力学问题无疑是一种十分有用的资料。  相似文献   

Two examples of spectral approach to source depth estimation in gravity and magnetics     

P. C. Pal  K. K. Khurana  P. Unnikrishnan 《Pure and Applied Geophysics》1978,117(4):772-783

Fourier transformation of gravity and magnetic anomalies from space to the frequency domain provides aready method for source depth estimation since progressively deeper sources are indicated by the lower frequency components of an anomaly. Two examples are presented here to demonstrate the efficacy of this approach. One example pertains to the interpretation of vertical intensity magnetic anomalies over a layered ultramafic body for estimating the thickness of relatively non-magnetic layer in it and map the dispositions of the layers. The other example is the estimation of crustal thickness in the Indian region from the Bouguer anomaly map. The spectral method is shown, by these two examples, to provide a rapid and elegant tool for the source depth estimation for magnetic and gravity data.  相似文献   

Systematic variations of mean travel-time residuals in space and time     

A. G. Prozorov 《Pure and Applied Geophysics》1977,115(3):675-692

Summary Mean travel-time residuals of P waves for the period 1964–1970 at stations in North America and Europe are well separated into large domains of positive and negative values. The spatial distribution of residuals in North America is in good agreement with the structure of the upper mantle obtained from Rayleigh wave dispersion and is in accord with magnitude anomalies and heat flow data. A systematic variation of residuals in time is found to be sensitive to major changes in the nature of the earthquake source distribution, as for example aftershocks, as well as to changes in methods of detection of first arrivals. Residuals at neighboring stations are correlated up to distances of the order of 2°. Half year mean residuals at stations within 2° distance from the epicenters of strong earthquakes have a sudden jump 1.5 years before the occurrence of an earthquake. A formal algorithm based on this pattern permits prediction of the times of all 16 earthquakes with magnitudeM7.5 occurring during the interval 1966–1972. Although the average duration of the alarm periods is about half the total time interval of the catalog, so that the algorithm has no practical importance, these results are statistically significant on a 99% level of confidence.  相似文献   

Further evidence for radial velocity anomalies in the lower mantle     

C. Wright  J. A. Lyons 《Pure and Applied Geophysics》1980,119(1):137-162

Summary Wright andLyons (1981) used a least-squares matching technique (LMM) and an adaptive processing method (ADP) to study the behaviour of slowness and azimuth measurements made on two synthetic interfering wavelets having different arrival vectors and onset times. We have applied these results to the analysis of real array seismograms. Some of the effects generated synthetically are frequently observed on real seismograms of earthquakes recorded at Yellowknife at distances close to 50° and 90°. We have also processed sufficient data to illustrate how the interference phenomenon can be used to confirm the presence of radial velocity anomalies in the lower mantle. NumerousP arrivals from South American earthquakes at distances between 78° and 98° suggest the presence of two radial velocity anomalies at depths close to 2400 and 2730 km below the Caribbean region; these anomalies also appear to vary laterally.Contribution No. 864 from the Earth Physics Branch.  相似文献   

An application of complex demodulation technique to geomagnetic data and conductivity anomaly studies     

A. K. Agarwal  B. P. Singh  N. Nityananda 《Journal of Earth System Science》1980,89(1):67-77

The method of complex demodulation has been used here to compute the amplitude and phase of a signal present in a geomagnetic series using, Banks’ method. It is found that the results are quite accurate when four or more continuous cycles of the signal of interest are present. The same limitations have also been observed when band-pass filters are used to isolate a signal. The information on phase is always correct. It is concluded that complex demodulation will give correct results for periodic variations like 11-year, 27-day, Sq or pulsations; but will give small values of amplitude for signals like sudden impulses or bays. The latter is not a limitation in conductivity studies where ratios likeZ/H, Z/D orH/D are mostly used in calculations. It has been shown that even with the records of one magnetic storm the cause of anomalies can be accurately identified which otherwise would need a large number of events.  相似文献