3D interpolation of grain
size distributions in the upper 5 m of the channel bed of three lower Rhine
distributaries
S.H.L.L. Gruijters, D. Maljers, J.G. Veldkamp
Netherlands Institute of Applied Geosciences, TNO Geology Division, PO
Box 80015, 3508 TA Utrecht, The Netherlands
Abstract
This article compares two methods to interpolate grain size
distributions to a 3D model (grid-size 25 × 25 × 0.2 m) of the upper 5 m of the
riverbed of three lower Rhine distributaries in The Netherlands. These models
have been used as input for morphological predictions of the effects of
maintenance and restructuring plans of the riverbed. Both methods use field
data from seismic surveys and vibrocore borings to construct
a 2.5 D layer model. Full grain size distributions within grid cells of 25 × 25
× 0.2 m have been obtained by interpolation within layers, using 3D Kriging,
thereby analyzing spatial variability over different scales. In the first
method measured grain size distributions have been interpolated. The second
method uses measured grain size distributions and synthetic grain size
distributions from estimated soil sample parameters (silt content, gravel
content, sand median). The combination of synthetic and measured GSD strongly
enhances the spatial variation in the interpolation result and prevents a
misrepresentation of lithologies in the model.
Keywords: Grain size
distribution modelling; Riverbed active layer;
Bifurcation; High resolution seismics; 3D Kriging
In: Physics
and Chemistry of the Earth, Parts A/B/C, Volume 30(4-5), 303-316, 2005 (DOI: http://dx.doi.org/10.1016/j.pce.2005.01.001)