Magnetic and gravity anomalies within the northern Norwegian margin, 67° to 71°N are generally interpreted in terms of a complex series of uplifted and rotated basement blocks. Some of the basement highs were previously not identified on seismic reflection data because they lie below basalt flows. Several shifts in polarity occur along the faults in the continental shelf and the adjacent onshore area. The individual segments of the fault complexes are connected by transfer zones, which occur as either: (1) transverse faults, e.g. the Lenvik transfer zone, or (2) twist zones, e.g. the Vesteralen transfer zone. The Vestfjorden Basin consists of two subbasins or half-grabens: one to the north with a border fault to the east and one to the south with a border fault to the west. Several basement faults on the continental shelf can be traced onto the mainland. A palaeomagnetic study of Vesteralen, Senja and Kvaloya has furnished temporal constraints on the near-shore fault activity.