Print Email Facebook Twitter Source depopulation potential and surface-wave tomography using a crosscorrelation method in a scattering medium Title Source depopulation potential and surface-wave tomography using a crosscorrelation method in a scattering medium Author Gouedard, P. Roux, P. Campillo, M. Verdel, A.R. Yao, H. Van der Hilst, R.D. Faculty Civil Engineering and Geosciences Department Geoscience & Engineering Date 2011-03-23 Abstract We use seismic prospecting data on a 40 × 40 regular grid of sources and receivers deployed on a 1 km × 1 km area to assess the feasibility and advantages of velocity analysis of the shallow subsurface by means of surface-wave tomography with Green's functions estimated from crosscorrelation. In a first application we measure Rayleigh-wave dispersion curves in a 1D equivalent medium. The assumption that the medium is laterally homogeneous allows using a simple projection scheme and averaging of crosscorrelation functions over the whole network. Because averaging suppresses noise, this method yields better signal-to-noise ratio than traditional active-source approaches, and the improvement can be estimated a priori from acquisition parameters. We find that high-quality dispersion curves can be obtained even when we reduce the number of active sources used as input for the correlations. Such source depopulation can achieve significant reduction in the cost of active source acquisition. In a second application we compare Rayleigh-wave group velocity tomography from raw and reconstructed data. We can demonstrate that the crosscorrelation approach yields group velocity maps that are similar to active source maps. Scattering has an importance here as it may enhance the crosscorrelation performance. We quantify the scattering properties of the medium using mean free path measurements from coherent and incoherent parts of the signal. We conclude that for first-order velocity analysis of the shallow subsurface, the use of crosscorrelation offers a cost-effective alternative to methods that rely exclusively on active sources. Subject correlation methodsgeophysical prospectinggeophysical signal processingGreen's function methodsRayleigh wavesseismologytomography To reference this document use: http://resolver.tudelft.nl/uuid:dc1eb372-1686-416c-89df-29bd007da4df DOI https://doi.org/10.1190/1.3535443 Publisher Society of Exploration Geophysicists ISSN 0016-8033 Source Geophysics, 76 (2), 2011 Part of collection Institutional Repository Document type journal article Rights (c) 2011 Society of Exploration Geophysicists Files PDF Verdel_2011.pdf 3.74 MB Close viewer /islandora/object/uuid:dc1eb372-1686-416c-89df-29bd007da4df/datastream/OBJ/view