Searched for:
(1 - 20 of 20)
document
Holicki, M.E. (author), Drijkoningen, G.G. (author), Wapenaar, C.P.A. (author)
We propose a novel directional decomposition operator for wavefield snapshots in heterogeneous-velocity media. The proposed operator demonstrates the link between the amplitude of pressure and particlevelocity plane waves in the wavenumber domain. The proposed operator requires two spatial Fourier transforms (one forward and one backward) per...
conference paper 2017
document
Bharadwaj, Pawan (author), Drijkoningen, G.G. (author), Mulder, W.A. (author), Tscharner, Thomas (author), Jenneskens, Rob (author)
The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier to interpret than compressional waves, as has...
conference paper 2016
document
Holicki, M.E. (author), Wapenaar, C.P.A. (author), Drijkoningen, G.G. (author)
We propose a novel acoustic decomposition operator for time slices, loosely based on conventional surface decomposition operators. The proposed operators hold for constant velocity models and require two 2D Fourier Transforms (one forward, one backward) per decomposed time slice per decomposition direction. We then demonstrate the capabilities...
conference paper 2016
document
Pisupati, P.B. (author), Mulder, W.A. (author), Drijkoningen, G.G. (author)
To overcome the local minima problem in FWI, we propose to use an auxiliary data-domain objective function during inversion. It reduces the data to a simpler form by squaring, followed by blurring to ensure that events that are too far apart can still interact during the inversion. As it effectively replaces seismic arrivals by bumps, we call it...
conference paper 2015
document
Drijkoningen, G.G. (author), Dieulangard, D. (author), Holicki, M.E. (author)
The feasibility of using an air gun near the sea floor as shear-wave source has been investigated. With an air gun near the sea floor, an evanescent P-wave in the water becomes a propagating S-wave in the sea floor, such that it seems that a pure shear-wave source has been used at the sea floor. This type of wave has been called a P*S wave. An...
conference paper 2015
document
Pisupati, P.B. (author), Mulder, W.A. (author), Drijkoningen, G.G. (author), Reijnen, R. (author)
In the near-surface with unconsolidated soils, shear properties can be well imaged, sometimes better than P-wave properties. To facilitate ground prediction ahead of a tunnel boring machine (TBM), active ‘surveys’ with shear-wave vibrators are carried out during boring. In such surveys, only a few shear-wave vibrators can be placed in front of...
conference paper 2015
document
Schaller, A.M. (author), Hunziker, J.W. (author), Streich, R. (author), Drijkoningen, G.G. (author)
We investigate potential benefits of measuring the vertical electric field component in addition to the routinely measured horizontal electric field components in onshore time-lapse controlled-source electromagnetics. Synthetic electromagnetic data based on a model of the Schoonebeek onshore oil field are used. We confirm that the vertical...
conference paper 2014
document
Kudarova, A. (author), Van Dalen, K.N. (author), Drijkoningen, G.G. (author)
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...
conference paper 2014
document
Kudarova, A. (author), van Dalen, K.N. (author), Drijkoningen, G.G. (author)
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...
conference paper 2014
document
Grobbe, N. (author), van der Neut, J.R. (author), Almagro Vidal, C. (author), Drijkoningen, G.G. (author), Wapenaar, C.P.A. (author)
Separation of recorded wavefields into downgoing and upgoing constituents is a technique that is used in many geophysical methods. The conventional, multi-component (MC) wavefield decomposition scheme makes use of different recorded wavefield components. In recent years, land acquisition designs have emerged that make use of shallow horizontal...
conference paper 2014
document
Pisupati, P.B. (author), Mulder, W.A. (author), Drijkoningen, G.G. (author)
With single-parameter full waveform inversion, estimating the inverse of the Hessian matrix will accelerate the convergence, but is computationally expensive. Therefore, an approximate Hessian, which is easier to compute, is often used. Similarly, in the case of multi-parameter full waveform inversion, the computation of the Hessian terms that...
conference paper 2014
document
Noorlandt, R.P. (author), Drijkoningen, G.G. (author), Faber, C.A.M. (author)
In this abstract we show the influence of vibrator drive level on the signal it produces. For that purpose a field survey was carried out using an INOVA's AHV-IV vehicle with a modified 266kN (60.000 lbf) vibrator. A single linear sweep was repeated at 10 different drive levels ranging from 5 to 90% at two locations. Each drive level was...
conference paper 2013
document
Diaferia, G. (author), Kruiver, P.P. (author), Drijkoningen, G.G. (author)
Analogous to the use of Rayleigh waves in MASW on land, Scholte waves can be used to derive shear wave velocity profiles for the subsurface under water. These profiles are useful for dredging operations, offshore wind farms, oil rigs and pipelines. We have determined the optimal acquisition set up for the detection Scholte waves in shallow water...
conference paper 2013
document
El Allouche, N. (author), Van der Neut, J.R. (author), Drijkoningen, G.G. (author)
Elastic wave decomposition, aiming at separating the converted modes from the P waves, is applied to high-resolution OBC data acquired in the River Danube, Hungary. The decomposition relies on accurate knowledge of the water-bottom elastic parameters and on a perfect sensor calibration and coupling. The available decomposition schemes require an...
conference paper 2013
document
Noorlandt, R.P. (author), Drijkoningen, G.G. (author), Schneider, R.M. (author)
In this paper we present a newly developed vertical seismic vibrator driven by linear motors. We explain the different components the vibrator consists of. We show that the harmonic distortion of the linear-motor vibrator signal is very small. We also show that, without applying a feedback loop on the pilot signal, the weighted-sum ground force...
conference paper 2012
document
Drijkoningen, G.G. (author), Allouche, N. (author)
In this paper we show that when an airgun source and a hydrophone streamer are situated in the vicinity of the water bottom, shear-related events are generated via the evanescent part of the P wave in the water. The shear-related events are not only the often-used surface/Scholte waves but also body Swaves which can be reflected/refracted in the...
conference paper 2012
document
Batenburg, P.A.W. (author), Gill, E.K.A. (author), Drijkoningen, G.G. (author), Toxopeus, G.J. (author)
A study was performed to determine the feasibility of reflection seismology for planetary geology taking into account present-day technology advances. An approach based on end-user requirements was applied to assure the scientific usefulness of the results. Thirty applications of a seismic-reflection system for space applications were determined...
conference paper 2010
document
Batenburg, P.A.W. (author), Gill, E.K.A. (author), Drijkoningen, G.G. (author), Foing, B.H. (author), Toxopeus, G. (author)
A feasibility study is conducted to determine whether reflection seismology systems can be used for planetary geology research. The focus is on systems with up to 20,000 seismic detectors, such as used today in Earth geological research and energy companies. The study follows a top-down systems engineering end-user approach starting with the...
conference paper 2009
document
El Allouche, N.E. (author), Drijkoningen, G.G. (author), Versteeg, W. (author), Simons, D.G. (author)
conference paper 2008
document
Vos, J. (author), Cremers, B.B. (author), Drijkoningen, G.G. (author), Fokkema, J.T. (author)
conference paper 1995
Searched for:
(1 - 20 of 20)