Neotectonics in Norway, Final Report

Abstract

Geodynamic modelling of the present crustal uplift indicates that the uplift of western Norway and northern Norway is partly due to other mechanisms that the glacioisostatic rebound. We have also deduced a new model based on the 'seismic pumping' mechanism to explain the observed correlation between land uplift and groundwater yield in Norway. Rock avalanches and landslides represent the most hazardous effects of earthquakes in Norway with its mountainous terrain, deep fjords and relatively large areas with unstable quick-clay. New seismic mini-arrays in the Ranafjorden area and the northern North Sea have sharply defined zones of increased seismicity. A total of 350 earthquakes have been detected in the outer Ranafjord area during the project period (2 1\/2 years) with magnitudes up to 2.8. This is very high onshore Baltic Shield areas. The return perios of magnitude 6 and 5 earthquakes have been estimated to 1500 and 130 years respectively. The M6 earthquake in 1819 in Mo i Rana triggered several rockfalls and a landslide.