The Møre-Trøndelag Fault Complex - an integrated study

The goal of the present study is to integrate geological and geophysical methods in order to improve our knowledge on the geometry and the mechanics of the Møre-Trøndelag Fault Complex (MTFC). The MTFC is a crustal-scale fault zone whose core has been exh umed during geological times. As such it represents a natural laboratory for understanding deep physical processes that lead to major earthquakes along similar fault zones that are active present-day. The MTFC represents also one of the key structures for the formation of the Mid-Norwegian continental margin, and knowledge of its structure will assist to any assessment of the future hydrocarbon potential of the area. Finally, although the MTFC is one of the most prominent fault zones of Norway its seismic potential remains poorly known. We will combine detailed structural fieldwork, gravity magnetic and resistivity surveys and high-resolution reflection seismic profiles where previous field studies have shown repeated reactivation since Caledonian time. A combination of high-resolution magnetic and gravity surveying and seismic methods will constitute our prime tools in order to elucidate the deep structure of the fault zone. Bedrock sampling and analysis of rock properties (seismic velocities, density, m agnetic susceptibility) will constrain the geophysical integrated modelling and the subsequent building of a 3D geometrical model for the fault zone. The resistivity surveys will be used to link the structures mapped a the surface with those imaged by mea ns of seismic reflections. The 3D model will be used to achieve a rheological model, itself constrained by detailed mapping of fault rocks observed in the field. The 3D fault model will shed new lights on the present and past mechanical behaviour of the f ault zone and its control on uplift/subsidence patterns through time.