Analysis of Severely Aliased Surface Waves from a 2D Seismic Reflection Line

ONNIS, L.,; OSELLA, A.,

Malmo

Congreso; Near Surface Geophysics; 2017

We perform an analysis of the surface waves present inshallow seismic reflection data. The survey is part of anenvironmental study of the Llancanelo Lake region(southern Mendoza Province, Argentina). (Osella et al.,2015; Violante et al., 2012)During the seismic reflection processing, surface waveswere entirely muted before stacking, due to their severespatial aliasing which precluded their removal bytraditional multichannel filters (Figure 1). The objective ofthe surface wave analysis was to derive complementaryinformation about the shallow subsurface (< 50 m),which is not properly resolved in the stacked section(Figure 2).The methodology comprises the determination of localRayleigh modal dispersion curves for different pointsalong the surveyed profile and their inversion using a 1Dalgorithm to obtain local shallow V profiles at each point. SBecause the effect of spatial aliasing is clearlyrecognized on f-k domain, we chose to image and pickthe dispersion curves on f-k amplitude spectra ratherthan on alternative domains.