Models for seismic wave propagation in periodically layered porous media

Several models are discussed for seismic wave propagation in periodically layered poroelastic media where layers represent mesoscopic-scale heterogeneities that are larger than the pore and grain sizes but smaller than the wavelength. The layers behave according to Biot’s theory. Wave propagation normal to the layering is considered and the...

Upscaling in porous media: Consequences of reducing the phase on the dynamic behavior of a homogenized medium

Effective-medium approaches are widely used to model initially heterogeneous systems: it saves computational time. In poroelasticity (two-phase media), it is advantageous to use one-phase effective medium if possible: it simplifies computations even more. In this paper we discuss situations where phase reduction introduces significant inaccuracy...

Time-stepping stability of continuous and discontinuous finite-element methods for 3-D wave propagation

We analyse the time-stepping stability for the 3-D acoustic wave equation, discretized on tetrahedral meshes. Two types of methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method. Combining the spatial discretization with the leap-frog time-stepping scheme, which is second...

Validation of an electroseismic and seismoelectric modeling code, for layered earth models, by the explicit homogeneous space solutions

We have developed an analytically based, energy fluxnormalized numerical modeling code (ESSEMOD), capable of modeling the wave propagation of all existing ElectroSeismic and SeismoElectric source-receiver combinations in horizontally layered configurations. We compare the results of several of these modeled source-receiver combinations in a...

Performance and scalability of finite-difference and finite-element wave-propagation modeling on Intel's Xeon Phi

With the rapid developments in parallel compute architectures, algorithms for seismic modeling and imaging need to be reconsidered in terms of parallelization. The aim of this paper is to compare scalability of seismic modeling algorithms: finite differences, continuous mass-lumped finite elements and discontinuous Galerkin finite elements. The...

Generalized minimum-phase relations for memory functions associated with wave phenomena

Effective poroelastic model for one-dimensional wave propagation

An effective poroelastic model is proposed that describes seismic attenuation and dispersion in periodically layeredmedia. In this model, the layers represent mesoscopic-scale heterogeneities (larger than the grain and pore sizes but smaller than the wavelength) that can occur both in fluid and solid properties. The proposed effectivemedium is...

Local time stepping with the discontinuous Galerkin method for wave propagation in 3D heterogeneous media

Modeling and imaging techniques for geophysics are extremely demanding in terms of computational resources. Seismic data attempt to resolve smaller scales and deeper targets in increasingly more complex geologic settings. Finite elements enable accurate simulation of time-dependent wave propagation in heterogeneous media. They are more costly...

Data matching for free-surface multiple attenuation by multidimensional deconvolution

A common strategy for surface-related multiple elimination of seismic data is to predict multiples by a convolutional model and subtract these adaptively from the input gathers. Problems can be posed by interfering multiples and primaries. Removing multiples by multidimensional deconvolution (MDD) (inversion) does not suffer from these problems....

Fast multifrequency focal beam analysis for 3D seismic acquisition geometry

A method for the efficient computation of multifrequency focal beams for 3D seismic acquisition geometry analysis has been developed. By computing them for all the frequency components of seismic data, single-frequency focal beams can be extended to multifrequency focal beams. However, this straightforward method involves considerable computer...

Fluid effect on wave propagation in heterogeneous porous media

Acoustic wave propagation through porous media is affected by the properties of the pore fluid and the matrix material. The acoustic velocity is extensively used for imaging of subsurface strata, and to predict petrophysical properties. In contrast, the attenuation (loss of wave energy) is not routinely used. This thesis reports the influence of...

Nonlinear surface waves over topography

As ocean surface waves radiate into shallow coastal areas and onto beaches, their lengths shorten, wave heights increase, and the wave shape transforms from nearsinusoidal to the characteristic saw-tooth shapes at the onset of breaking; in the ensuing breaking process the wave energy is cascaded to small-scale turbulent motions in the surf zone....

Experimental study of blockage of monochromatic waves by counter currents

Blockage of waves by a current can occur if waves are propagating on a spatially varying opposing current in which the velocity is increasing in the wave propagation direction. The ongoing waves become shorter and steeper while they are propagating against the current. Blocking occurs at the location where the opposing current strength is the...

Analysis of the dynamic response of layered, elastic media by means of the Fast Fourier Transform

A straightforward method is presented to calculate the three-dimensional response of layered, elastic half-spaces to a dynamic surface loading. The derivation of the method is performed in the wavenumber-frequency domain. Space-frequency domain results are subsequently obtained through the application of the Fast Fourier Transform. The results...

Golfvoortplanting in slagaderen

Please note that only this summary is in english. The rest of the report is in dutch only. This paper deals with the wave propagation of harmonic travelling waves through an incompressible, Newtonian fluid contained within an elastic tube with homogeneous and isotropic wall material. In particular the next questions are considered: 1) What is...

Propagation of tides and similar waves

Development of mathematical methods (digital and analog) for the computation of tides in seas and estuaries. This work is the basis for the numerical tidal computations, as well as the development of the analog computer DELTAR to predict tides in estuaries.