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DDC:
550 - Earth sciences
Abstract:
The present geological setting west of Svalbard closely parallels the situation off mid-Norway after the last glaciation, when crustal unloading by melting of ice induced very large earthquakes. The modern Svalbard margin is characterized by an active fluid flow system in continental margin sediments consisting of inter-layered contourite deposits and glacigenic debris flows. Both unloading earthquakes and overpressures have been identified as key factors causing several mega-landslides off Norway during early Holocene deglaciation. The most prominent event was the Storegga Slide 8200 years BP which caused a tsunami up to 23 m high on the Faroe and Shetland islands. Numerical tsunami modeling indicates a smaller (100 m high and 130 km wide) submarine landslide west of Svalbard, which is consistent with the geological information available for the area, would cause a tsunami capable of reaching northwest Europe and threatening coastal areas. Although newly collected seismic data do not show clear precursors to incipient slope failure it may be sensible to install a tsunami warning system based on tilt-meters, which would give a warning time of one to four hours.
