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61.
Yinpo Xu Cheng Yin Xuefeng Zou Yudong Ni Yingjie Pan Liangjun Xu 《Geophysical Prospecting》2020,68(4):1228-1252
As the application of high-density high-efficiency acquisition technology becomes more and more wide, the areas with complex surface conditions gradually become target exploration areas, and the first-break picking work of massive low signal-to-noise ratio data is a big challenge. The traditional method spends a lot of manpower and time to interactively pick first breaks, a large amount of interactive work affects the accuracy and efficiency of picking. In order to overcome the shortcoming that traditional methods have weak anti-noise to low signal-to-noise ratio primary wave, this paper proposes a high accurate automated first-break picking method for low signal-to-noise ratio primary wave from high-density acquisition in areas with a complex surface. Firstly, this method determines first-break time window using multi-azimuth spatial interpolation technology; then it uses the improved clustering algorithm to initially pick first breaks and then perform multi-angle comprehensive quality evaluation to first breaks according to the following sequence: ‘single trace → spread → single shot → multiple shots’ to identify the abnormal first breaks; finally it determines the optimal path through the constructed evaluation function and using the ant colony algorithm to correct abnormal first breaks. Multi-azimuth time window spatial interpolation technology provides the base for accurately picking first-break time; the clustering algorithm can effectively improve the picking accuracy rate of low signal-to-noise ratio primary waves; the multi-angle comprehensive quality evaluation can accurately and effectively eliminate abnormal first breaks; the ant colony algorithm can effectively improve the correction quality of low signal-to-noise ratio abnormal first breaks. By example analysis and comparing with the commonly used Akaike Information Criterion method, the automated first-break picking theory and technology studied in this paper has high picking accuracy and the ability to stably process low signal-to-noise ratio seismic data, has a significant effect on seismic records from high-density acquisition in areas with a complex surface and can meet the requirements of accuracy and efficiency for massive data near-surface modelling and statics calculation. 相似文献
62.
人们认识自然总是从实践到理论,再从理论到实践.没有理论指导的实践是盲目的实践,没有实践基础的理论是空洞的理论,只有理论与实践密切结合,才能有所发现,有所进步. 相似文献
63.
本文研究了东北深震、缅甸中深震、渤海周围地震及川滇地震在活动进程中的关系。在地域分布上彼此相连。并呈以北东向斜贯中国东部浑然为有机整体巨大的地震带。同时还研究了东北深震与华北东部的渤海周围地震以及缅甸中深震与川滇地震活动的相关性和前兆性。指出了这些特点,对华北东部地震和川滇地震的预测是十分有意义的。文章在最后还讨论了太平洋、印度、欧亚三大板块的相互作用可能是巨大地震带形成的主要条件和产生变动的重要的动力因素。 相似文献
64.
Cheh Pan 《Pure and Applied Geophysics》1973,111(1):2177-2206
Summary A new approach to the determination of the interval and average seismic velocities and thickness of arbitrarily dipping subsurface rock layers from surface travel time measurement is presented. The method is referred to as thegeometric recursion. Its derivation is based upon the geometry of the seismic ray paths between a shotpoint and a geophone, and is basically an extension of Gardner's equation of dip correction. Travel time measurements at and distance between the shotpoint and the geophone and apparent dip angles of the layers are needed in using the techniques. The values determined with the new method are compared with those from two existing methods that are applicable only for the horizontal layers. The accuracy and shortcomings of these methods are then analyzed and discussed with real examples as illustrations. The main computing technique used in the method is the iterative approximation of the undetermined but interrelated subsurface parameters in common loops. The method is practical to use, particularly when the travel time measurements in an area are not redundant. Its efficiency is dependent primarily upon the accuracy of the travel time measurements as well as the effective control of the shortcomings of the method. 相似文献
65.
T. N. Krishnamurti John Molinari Hua-Lu Pan Vince Wong 《Pure and Applied Geophysics》1977,115(5-6):1357-1372
In this short paper we have identified some of the modelling groups that have the capability of simulating or carrying out short range numerical weather prediction over the monsoon belt. We have next outlined some of the important and desirable ingredients for a multilevel primitive equation model over the tropics, with most of the emphasis on the present version of Florida State University's Tropical Prediction Model. Finally, we present briefly some important results based on the present version of our prediction models that relate to the NWP efforts over the monsoon belt. Here we have identified the importance of mountains, convection, the radiative heating balance of the earth's surface, and the planetary boundary layer over the Arabian Sea. 相似文献
66.
We investigate the estimation of interfacial areas, curvatures, and common curve lengths in multiphase porous medium systems. Algorithms are developed to obtain estimates of these quantities based upon a variety of potential data sources and estimation approaches. The accuracy of the derived approximations are evaluated as a function of the data type and resolution of the data. The methods advanced improve upon standard approaches now in use and show excellent accuracy at resolutions on the order of five lattice points per minimum radius of curvature of the object being resolved. Finally, we suggest a promising class of extensions that could lead to further improvements in the accuracy of such methods. 相似文献
67.
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69.
Hongchun Wang Ping Jin Changzhou Pan Weiguo Xiao Northwest Institute of Nuclear Technology Xi'an China 《地震学报(英文版)》2009,(1):13-20
The relative amplitude method(RAM) is more suitable for source inversion of low magnitude earthquakes because it avoids the modeling of short-period waveforms.We introduced an improved relative amplitude method(IRAM) which is more robust in practical cases.The IRAM uses a certain function to quantify the fitness between the observed and the predicted relative amplitudes among direct P wave,surface reflected pP and sP waves for a given focal mechanism.Using the IRAM,we got the fault-plane solutions of two ea... 相似文献
70.
利用核磁共振(NuclearMagneticResonance缩写为NMR)技术探查地下水仅有二十多年的历史,文中简要介绍了NMR找水方法的发展状况,原理和方法特点,重点介绍了中国地质大学(武汉)利用NMR找水方法在中国一些地区找水取得的成效,最后指出了NMR找水方法的发展趋势。 相似文献