Hein Raat

TNO  - Geological Survey of the Netherlands (GSN) develops several subsurface models. Most of the published models are 'layer-based' models with national coverage, consisting of stratigraphical or hydrogeological layers with uniform properties. One of the models (GeoTOP) describes the upper 30m of the subsurface in millions of voxels (100 x 100 x 0.5m) each containing information on stratigraphy, lithology and the probability of occurrence for the different lithological classes. The GeoTOP modelling program was initiated in 2007 starting in the southwestern part of the Netherlands and has a regional approach, covering 13 areas. More than 90% of the available borehole data in DINO (a relational database containing ~525.000 bore holes maintained by GSN) is used and focus has been on the Holocene sequence, which has less detail in all other published models. Seven regions have been released covering around 55% of the country by the end of May 2016.