1887

Abstract

The properties of sand are important for its suitability for the use in construction works. For dredgers, this information needs to be available in advance of dredging activities. Shear wave velocities are linked to the strength of the sediment. In underwater environments, shear wave velocities can be extracted from seismic data using the dispersive properties of Scholte waves. We used forward modelling to investigate whether we can regard Scholte waves as their equivalent on land, Rayleigh waves. The difference between Rayleigh and Scholte waves is related to the relative water depth and the Poisson ratio distribution. For a halfspace of unconsolidated muddy sediments (high Poisson ratio) on deep water layer, the Scholte wave velocity is nearly 15% lower than the Rayleigh wave velocity. For sandstone (low Poisson ratio), there is no difference. When the water is shallow, the Scholte wave velocity deviates from Rayleigh wave velocity by less than 5%. Shear wave velocities were extracted from Scholte waves observed in data sets from the intertidal Wadden Sea (The Netherlands) and the river Danube near the village of Kulcs (Hungary). Based on the results from the forward modelling, we treated the Scholte waves as Rayleigh waves. The shear wave velocities in the top layer of the Wadden Sea sediments were approximately 150 m/s, which fall in the expected range for poorly consolidated material. The shear wave velocities of the Kulcs sediment were higher (400 to 600 m/s). The transition from clay to sand as apparent from a borehole log was successfully recovered in the subsurface shear wave velocity model.

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/content/papers/10.3997/2214-4609-pdb.150.A05
2010-01-20
2020-09-25
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http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.150.A05
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