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Content. Introduction The 3D geological model of the Mont Terri anticline Outlook. Definition of 3D Geology * “3D geology is the interaction of 3D modelling, 3D visualization, data handling and analysis” * by the Swiss Geological Survey. Introduction - Background.
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Content • Introduction • The 3D geological model of the Mont Terri anticline • Outlook Definition of 3D Geology * “3D geology is the interaction of 3D modelling, 3D visualization, data handling and analysis” * by the Swiss Geological Survey
Introduction - Background Why working in the domain of 3D geology? • Geology is 3D • Key technology • Great importance Supply models for further applications First step • 3D model of the Mont Terri anticline
Introduction – The Mont Terri model • Aims • To develop a 3D model of the Mont Terri anticline • To describe the necessary steps in a “cook-book” • To present the 3D model as movie & VRML-scene • Side-effect • To check the consistency of 2D profiles • Methodology • Using maps, measurements etc. as input data • Deriving a “simplified model” of the tectonic setting • Iterative refinement of the model
Introduction – The Mont Terri model Team Modelling • ISSKA, La-Chaux-de-Fonds • Geotechnisches Institut, St. Ursanne Project owner & reviewing • swisstopo, Swiss Geological Survey
Introduction – Tectonic interpretation of the Mont Terri region Based on the Geologic Atlas of Switzerland 1:25’000; sheet ”St.Ursanne”; Laubscher (1963); modified by C. Nussbaum
Introduction – 3D simplified block diagrams of the Mont Terri anticline Position of Mont Terri rock laboratory Nussbaum & Bossart (2008), in Bossart and Thury, swisstopo report
3D model – Basic data aquisition Geological data • Geologic Atlas of Switzerland 1:25‘000, sheet „St. Ursanne“ • Azimuth & dip measurements • Geological cross-sections and reports supplied by science (Uni Basel), industry and SBB • Geological maps along Mont Terri galleries Other data • DEM 25 • Aerial photos • Construction data of the Mont Terri rock laboratory • Layouts of highway and railway tunnels as well as abandoned limestone quarry of St. Ursanne
1b 1a Data preparation Create structural model Transfer to modelling software 2 Inter-/extrapolation modelling process Check geological consistency 4a 4b Modify structural model 3 Create new data no no OK? yes 5 Complete final model 3D model – Applied methodology Basic data aquisition
3D model – Challenges Difficulties appeared during model construction due to: • Data density • heterogenous spatial distribution • Data resolution • tunnel cross-sections vs. geological profiles • Ages of samples • e.g. 1873-1875 tunnel cross-sections provided by the SBB • Diverging conceptual models of the geological structure • publishing ages of basic data
3D model – Results • 3D model • Software: Cinema 4D • 3D scene • VRML-format • Movie presenting the model • .avi-format (see movie at swisstopo booth) • Project report
3D model – Conclusions • 3D geology can help to assure quality standards of 2D data • Identification of contradictions of 2D cross-sections • Verification of „plain strain hypothesis“ • 3D geology is time consuming • 500-800h modelling work • 3D geology does not provide one stop results, it is an iterative approach • Construction of detailed models by passing through several loops • 3D geology is always interpretation (like conventional geological cross-sections and maps • Results represent only an approximation to the real settings
Outlook – Mont Terri • Combination of the existing Borehole Information System and 3D model • Finite element modelling (hydrodynamic, stress field etc.)
Outlook – General Short-term • Development of a conceptual background for the setup and application of the 3D geology • Implementation of geological 3D modelling software • Development of 3D models of selected regions Mid-term • Integration of 3D data into swisstopo Data Management Systems • Establishing of partnerships and networks • Definition of interfaces to other domains Long-term • Development of nationwide 3D geological models
The end - Questions & answers Thank you for your attention. 3D model available at: http://www.isska.ch/SwissTopo3D/index.html Contact: roland.baumberger@swisstopo.ch