Gas Hydrates at Storegga Slide

Abstract

The Storegga Slide (Bugge 1983, Bugge et al. 1987) is the worid’s largest known sediment slide (Fig. 1).The cause of this three-phase slide event at 8,200 ka (Haflidason et al. 2001) with a maximum run-out distance of approx. 800 km (Fig. 1) is not well known. The cause has been inferred to be related to earthquakes and/or gas and gas hydrates because a well-defined Bottom Simulating Reflector (BSR) occurs on seismic profiles from the NE flanks of the current slide scar (Bugge 1983; Mienert et al. 1998) (Fig. 2). The presence of gas hydrate-bearing sediments is generally inferred from the presence of such a characteristic BSR (Stoll and Bryan 1979). Open image in new window Fig. 1. Location of the three phases of Storegga Slide on the Norwegian continental margin. The black arrow indicates the location of the seismic line shown in Fig. 2, while the white arrows indicate the direction of the mass flows during the Storegga Slide events. The white numbers refer to the run-out distances Open image in new window Fig.2. Multichannel (P-wave) seismic line NH 9651-202 aeross the northern side wall of the Storegga Slide. The presence of gas hydrate-bearing sediments is inferred from the presence of a characteristic BSR indicated by arrows. The location of the multi-component ocean bottom cable line is marked by a framed area shown in Fig. 3