Stress transfer in the Storegga area, offshore mid-Norway

The recently discovered large gas-field 'Ormen Lange' within the Storegga submarine slide area, offshore mid-Norway, poses important questions as to the origin of these large submarine slides and their possible implications in terms of the safety of the development and the production. In this respect, the present study was initiated with the main objective of investigating the possibility of stress transfer as triggering mechanism for multiple earthquake occurrence and hence for the Storegga submarine slide ca. 8200 years before present (BP). Stress changes following different scenario earthquakes along the selected faults in the area are modeled and computed for a number of cases. Using the Coulomb failure criterion we demonstrate the possibility of large earthquakes triggering multiple ruptures along neighbouring fault segments. The combined effect of the co-seismic slip and strong ground shaking due to a large earthquake (M similar to 7) accompanied by the stress transfer on the optimally oriented normal fault-planes which are analogous to the slide-scar, may have played an important role for the triggering of the Storegga submarine slide. (c) 2005 Elsevier Ltd. All rights reserved.