Active normal fault control on landscape and rock-slope failure in Northern Norway

Structural, geomorphic, and interferometric synthetic aperture radar (InSAR) surface displacement data show that uplift of the northernmost onshore Scandinavian passive margin is associated with active normal faulting and anomalous clusters of landslides. Regional-scale normal faults separate alpine footwall ranges with impressive range-front scarps from more gentle hanging-wall topography. In the Lyngen region, rockslides, sackung features (i.e., deep-seated slope gravitational deformation), and active faults cluster inside an approximately 1000 km (super 2) area of hanging-wall subsidence parallel to an approximately 30-km-long, faceted range-front scarp. From postglacial to recent time, rockslides have been released along the main range front and other propagating scarps, both in the footwall range and in structurally controlled, glacially oversteepened valleys of the hanging wall. The active rockslides, moving at rates of >10 mm/yr, show a variety of relationships to the controlling structures, reflecting tectonic as well as gravitational faulting. Recent and present-day landscape evolution and large-volume rockslide distribution in Scandinavia should be viewed from the perspective of tectonic processes involving active normal faults.