The dating and morphometry of the Storegga Slide

Abstract

The Storegga Slide has affected an area of approximately 95 000 km 2, and a sediment volume in the range of approximately 2400–3200 km 3 has been displaced. Around 250 km 3 of the volume has been deposited as turbidite sediments in the Norway Basin. This volume places the Storegga Slide event as one of the world's largest exposed submarine slides. Based on a comprehensive database, detailed morphological investigations and a dating programme have been performed to reveal the slide process and the timing of the slide. To date the slide event, detailed analyses of 89 cores within the Storegga Slide region have been undertaken. The investigations conclude: (a) The main Storegga Slide event represents one retrogressive event dated to be 7250±250 14C yrs BP or approximately 8100±250 cal. yrs BP. This age also corresponds with the age of a tsunami found along the western coast of Norway. (b) A few minor slide/slump events have been identified along the northern Storegga Slide escarpment, dated to be c. 5000 14C yrs BP and 2500–3000 14C yrs BP or approximately 5700 and 2200–2800 cal. yrs BP. The total volume of these events is interpreted to be less than 1 km 3 or c. 0.1% of the total volume calculated for the main Storegga Slide event. (c) The statistical analyses carried out on the lobes morphometrical parameters show a fairly good correlation ( R 2=0.8–0.9) between the smallest and the medium/large size debris lobes within the Ormen Lange Field area. This means that the rheological properties for this area can be described as fairly uniform for the slide masses and scaling of the morphometrical parameters should be possible with a great confidence.