The Åknes rockslide site in western Norway has gained much attention due to the potentially catastrophic consequences of a rock slope failure which could trigger a tsunami in the fjord below and endanger local villages and visiting tourists. An extensive monitoring and investigation programme was initiated in 2004 and a large amount of data has been gathered. A careful understanding of the complex rock slope geometry, based on these combined datasets, is essential for detailed stability analyses of the Åknes rockslide site and for prediction of the size of the potential slope failure. This paper reports on an integral part of this effort, the geovisualization, geometric modelling and volume estimation of the potentially unstable parts of the site. A custom-written, 3D software application formed the interactive platform used for visually analysing combinations of geophysical, geological and engineering geological data and for estimating the geometric extent of the basal sliding surface(s) on which the slope failure may potentially occur. Three scenarios were developed for different geometries of the sliding surface and the overall volumes of rock involved in each scenario were calculated.