Analogue modelling is a well-established technique to investigate the evolution of tectonic structures in the Earth's crust and lithosphere. Scaled analogue models offer the opportunity to determine the relation between imposed boundary conditions and the resulting structures. The strength of such models lies in stimulating the conception of testable hypotheses about the development of tectonic structures in nature.
The Tectonic Laboratory at the University of Bern (TecLab Bern) offers innovative and state-of-the-art facilities to model and analyse in detail a large variety of tectonic settings. Analogue models can be analysed by X-ray computed tomography (XRCT) using a 64-slice Siemens Somaton Definition AS medical scanner. XRCT is a technique which permits visualisation of the interior of a model without destroyig it, hence allowing an in-depth analysis of the 3-D geometry of model structures. Full 3D imaging of analogue models using XRCT allows the reconstruction of any desired section, be it horizontal, vertical or oblique and can provide constraints for seismic analysis of compex tectonic zones where seismic data are often fragmentary and difficult to interpret.
XRCT analysis of analogue models at regular time intervals makes it possible to understand the 3D evolution of structures in time (4D). 4D XRCT data sets obtained from analogue models provide the opportunity to re-run the experiment on the computer screen and thus represents a valuable database not only for seismic interpreters but also for teaching and outreach purposes.
Digital volume correlation (DVC) techniques on XRCT volumetric data can be used to quantify the 3D spatial and temporal strain patterns inside analogue models at high resolution. Such strain quantification of analogue experiments is of great importance when comparing analogue models with numerical models tudies. We have successfully applied DVC to models consisting of both brittle and viscous analogue model materials.
The TecLab Bern has several deformation devices, including an innovate experimental apparatus (whose size is adapted for XRCT analysis) with computer-controlled stepper motors that permits the combined displacement of baseplates and sidewalls allowing oblique deformational movements (oblique extension, oblique shortening). Another device allows the simulation of extensional rotational movements about a pivoting axis, and its size also permits analysis by medical XRCT scanning.
Please find further informations, photos and animations here: http://www.geo.unibe.ch/research/tectonics/laboratories/tectonic_modelling_lab/index_eng.html
