Calculation of the third and higher travel‐time derivatives in isotropic and anisotropic media

1999 ◽  
Author(s):  
Luděk Klimeš
Keyword(s):  
Travel Time ◽  
Anisotropic Media ◽  
The Third

scholarly journals Impacts of the Qinghai–Tibet Railway on Accessibility and Economic Linkage of the Third Pole

2018 ◽  
Vol 10 (11) ◽  
pp. 3982 ◽  
Author(s):  
Shicheng Li ◽  
Jian Gong ◽  
Qinghai Deng ◽  
Tianyu Zhou
Keyword(s):  
Sustainable Development ◽  
Travel Time ◽  
Eastern China ◽  
Weighted Average ◽  
Spatial Disparity ◽  
The Sustainable Development ◽  
Capital Cities ◽  
The Third ◽  
Average Travel Time ◽  
Economic Linkages

Constructing the Qinghai–Tibet Railway (QTR) was a landmark project and was beneficial to the sustainable development of the Third Pole. To understand the sustainable development of remote regions by the provision of railway, we studied the QTR’s impact on accessibilities and economic linkages for four cities in the Third Pole, Xining, Golmud, Nagqu, and Lhasa, and between these four cities and 29 capital cities in mid-eastern China. First, employing average shortest travel time (ASTT) and weighted average travel time (WATT) as indicators, we calculated the railway-based accessibilities for June 2006 and January 2013. Then, using a gravity model, railway-based economic linkages were determined. The results demonstrate that: (i) ASTT for Xining–Golmud decreased by 4.14 h from June 2006 to January 2013. Both ASTT and WATT indicated that the accessibilities of the four cities and between these four cities and 29 capital cities in mid-eastern China improved significantly, and the spatial disparity in accessibility for the four cities decreased, which increased the balance and sustainability of the transportation system; (ii) the average contribution rate of the QTR to improving economic linkages for six routes among the four cities was 25.29%, with the Xining–Nagqu and Nagqu–Lhasa linkages improving most significantly; (iii) the QTR strengthened economic linkages between the four cities and mid-eastern cities. Because of the QTR, the economic linkages between the four cities and 29 capital cities increased 27.58% on average. The spatial disparity in interurban economic linkages also decreased. Transporting products from Tibet should be promoted to strengthen the sustainability of economic growth.

Travel time curves for complex inhomogeneous slightly anisotropic media

1984 ◽  
Vol 28 (4) ◽  
pp. 393-406 ◽  
Author(s):  
Petr Firbas ◽  
J. Vaněk
Keyword(s):  
Travel Time ◽  
Anisotropic Media

The generation of the third harmonic in highly anisotropic media near the percolation threshold

2000 ◽  
Vol 45 (2) ◽  
pp. 194-198 ◽  
Author(s):  
A. A. Snarskii ◽  
K. V. Slipchenko ◽  
A. M. Satanin
Keyword(s):  
Percolation Threshold ◽  
Anisotropic Media ◽  
Third Harmonic ◽  
The Third

scholarly journals Radiation pattern analyses for seismic multi-parameter inversion of HTI anisotropic media

2019 ◽  
Author(s):  
Fengxia Gao ◽  
Yanghua Wang
Keyword(s):  
Waveform Inversion ◽  
Anisotropic Media ◽  
The Third ◽  
Seismic Waveform ◽  
Parameter Inversion ◽  
Stage Scheme ◽  
Hti Media ◽  
Transverse Isotropic ◽  
Anisotropy Parameters ◽  
Elastic Coefficients

Abstract In seismic waveform inversion, selecting an optimal multi-parameter group is a key step to derive an accurate subsurface model for characterising hydrocarbon reservoirs. There are three parameterizations for the horizontal transverse isotropic (HTI) media, and each parameterization consists of five parameters. The first parameterization (P-I) consists of two velocities and three anisotropy parameters, the second (P-II) consists of five elastic coefficients and the third (P-III) consists of five velocity parameters. The radiation patterns of these three parameterizations indicate a strong interference among five parameters. An effective inversion strategy is a two-stage scheme that first inverts for the velocities or velocity-related parameters and then inverts for all five parameters simultaneously. The inversion results clearly demonstrate that P-I is the best parameterization for seismic waveform inversion in HTI anisotropic media.

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