Simultaneous pre‐normal moveout and post‐normal moveout deconvolution

Geophysics ◽  
1986 ◽  
Vol 51 (7) ◽  
pp. 1341-1354 ◽  
Author(s):  
Jon F. Claerbout
Keyword(s):  
Field Data ◽  
Sequential Estimation ◽  
Wave Theory ◽  
Downward Continuation ◽  
Simultaneous Estimation ◽  
Test Cases ◽  
Linearized Theory ◽  
Spherical Divergence

Wave theory justifies both pre‐ and post‐NMO deconvolution, but the filters should be estimated simultaneously, not sequentially. A linearized theory enables simultaneous estimation of the two filters. The theory incorporates spherical divergence independently from statistical weighting. Field data test cases show the expected interaction between NMO and deconvolution. The tests were not able to establish that simultaneous estimation is superior to sequential estimation. The difficulty is ascribed to the inadequacy of NMO as a downward continuation process.

A stable iterative downward continuation of potential field data

2013 ◽  
Vol 98 ◽  
pp. 205-211 ◽  
Author(s):  
Guoqing Ma ◽  
Cai Liu ◽  
Danian Huang ◽  
Lili Li
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Downward Continuation ◽  
Potential Field Data

scholarly journals Review of Historical Dam-Break Events and Laboratory Tests on Real Topography for the Validation of Numerical Models

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1968
Author(s):  
Francesca Aureli ◽  
Andrea Maranzoni ◽  
Gabriella Petaccia
Keyword(s):  
Field Test ◽  
Field Data ◽  
Flood Hazard ◽  
Numerical Models ◽  
Data Access ◽  
Dam Break ◽  
Physical Models ◽  
Real Field ◽  
Test Cases ◽  
Validation Data

Dam break inundation mapping is essential for risk management and mitigation, emergency action planning, and potential consequences assessment. To quantify flood hazard associated with dam failures, flooding variables must be predicted by efficient and robust numerical models capable to effectively cope with the computational difficulties posed by complex flows on real topographies. Validation against real-field data of historical dam-breaks is extremely useful to verify models’ capabilities and accuracy. However, such catastrophic events are rather infrequent, and available data on the breaching mechanism and downstream flooding are usually inaccurate and incomplete. Nevertheless, in some cases, real-field data collected after the event (mainly breach size, maximum water depths and flood wave arrival times at selected locations, water marks, and extent of flooded areas) are adequate to set up valuable and significant test cases, provided that all other data required to perform numerical simulations are available (mainly topographic data of the floodable area and input parameters defining the dam-break scenario). This paper provides a review of the historical dam-break events for which real-field datasets useful for validation purposes can be retrieved in the literature. The resulting real-field test cases are divided into well-documented test cases, for which extensive and complete data are already available, and cases with partial or inaccurate datasets. Type and quality of the available data are specified for each case. Finally, validation data provided by dam-break studies on physical models reproducing real topographies are presented and discussed. This review aims at helping dam-break modelers: (a) to select the most suitable real-field test cases for validating their numerical models, (b) to facilitate data access by indicating relevant bibliographic references, and (c) to identify test cases of potential interest worthy of further research.

An improved regularized downward continuation of potential field data

2014 ◽  
Vol 106 ◽  
pp. 114-118 ◽  
Author(s):  
Xiaoniu Zeng ◽  
Daizhi Liu ◽  
Xihai Li ◽  
Dingxin Chen ◽  
Chao Niu
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Downward Continuation ◽  
Potential Field Data

scholarly journals Initial value problems in water wave theory

1963 ◽  
Vol 3 (3) ◽  
pp. 340-350 ◽  
Author(s):  
A. G. Mackie
Keyword(s):  
Initial Value Problems ◽  
Complete Solution ◽  
Wave Theory ◽  
Minor Role ◽  
Axially Symmetric ◽  
Initial Value ◽  
Hydrodynamic Impact ◽  
Linearized Theory ◽  
A Minor ◽  
Thin Wedge

The work described in this paper grew out of an attempt to generalize some results obtained in an earlier paper [4] on the water entry problem of a thin wedge or cone into an incompressible fluid. The object of the generalization was to include the effect of gravity terms. In most papers on hydrodynamic impact it is considered permissible to neglect this effect since gravity terms might be expected to play a minor role in the initial stages of the motion. However, it seems desirable to investigate the effect of including gravity terms in order both to examine the later stages of the motion and to estimate to what extent their neglect is justified in the early stages. It will be seen that it is possible to develop a fairly complete solution for the normal entry of a thin symmetric body, both for two-dimensional and axially symmetric cases, on the basis of a linearized theory. The restriction to a linearized theory means that the whole field of analysis associated with the theory of surface waves of small amplitude becomes available. Most of the problems considered in this paper are initial value problems in which the whole fluid is at rest at t = 0.

Downward continuation of refracted arrivals to determine shallow structure

Geophysics ◽  
1987 ◽  
Vol 52 (9) ◽  
pp. 1188-1198 ◽  
Author(s):  
N. Ross Hill
Keyword(s):  
Wave Field ◽  
Field Data ◽  
Complex Structure ◽  
Synthetic Data ◽  
Downward Continuation ◽  
Near Surface ◽  
Angle Method ◽  
Seismic Images ◽  
Shallow Structure ◽  
Interpretation Method

Information contained in refracted arrivals often can determine shallow, complex structure within the earth. An established way of interpreting refraction arrivals employs graphical construction of wavefronts. Here I extend this graphical method by using numerical downward continuation techniques. For examples of synthetic data and field data, seismic images of irregular interfaces are formed by downward continuing refracted arrivals. For a field‐data example, the image formed from the refraction arrivals is used to correct time‐delay anomalies caused by irregular near‐surface structure. Incorporation of downward continuation into refraction interpretation has several advantages. The method reduces complications due to raypath effects, diffractions, and shadow zones in the refracted arrivals. In addition, this interpretation method reduces the labor and ambiguities associated with identifying first breaks. p‐tau decomposition of the wave field provides a wide‐angle method for downward continuation of refracted arrivals. This method of downward continuation is well suited for refracted arrivals for several reasons. The method allows convenient evaluation of the wave field beneath an irregular recording datum, and it helps overcome spatial aliasing. Also, the calculations can easily be limited to the region of p‐tau space that contains the refracted arrival.

scholarly journals Improved Downward Continuation of Potential Field Data

2003 ◽  
Vol 34 (4) ◽  
pp. 249-256 ◽  
Author(s):  
Herve Trompat ◽  
Fabio Boschetti ◽  
Peter Hornby
Keyword(s):  
Potential Field ◽  
Field Data ◽  
Downward Continuation ◽  
Potential Field Data
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