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Tsunami generation from submarine gravity mass flows is investigated using linear two-dimensional analytical models, a simplified slide geometry, and a prescribed sub-critical slide velocity. Slide characteristics as maximum slide velocity, initial acceleration, slide length, and thickness, are all found to determine the characteristics of the tsunami. Effects of dispersion usually turn out to be of minor practical importance. Tsunamis due to retrogressive slides are generally smaller than for a similar fixed shaped slide with the same characteristics due to an increased duration of slide mass mobilisation. However, above the rear of the slide, the surface elevation can also be increased for small time lags.

Deposits from the Storegga tsunami have been found in coastal areas around the Norwegian Sea and North Sea, from the northeast coast of England to beyond the Arctic Circle in northern Norway. The tsunami deposits reach onshore elevations of 10–12 m above sea level of their time in western Norway, 3–6 m in northeast Scotland and above 20 m on the Shetland Islands. These elevations are compared with surface (wave) elevations derived from a numerical simulation of the Storegga slide. A good agreement is obtained for a retrogressive slide that descends at 25–30 m/s, and that has short time lags of 15–20 s between each individual slide-block.

Tsunami generation by submarine slides have been a major concern in the risk assessment for the Ormen Lange gas field off Western Norway. Tsunamis are analysed with a numerical model supplemented by an analytical one. Both models show how slide extensions and slide dynamics influence the tsunamigenic potential for a large region. Several combinations of slide parameters were tested, and the product of initial acceleration and the volume of the slide gave the best correlation with the maximum surface elevation for the near coastal domain.