12
using recent bottom topography, the Storegga tsunami reached the central North Sea
6 hours after crossing the shelf edge. The possible recurrence of a slope failure at the
Norwegian continental shelf break on the order of the Storegga slide is discussed
controversially (see section 10.1).
i5*iv 1 0’W 5‘W O’ 5"E 10‘E
• Storegga tsunami deposits Q Run-up of tsunami deposits
Fig. 3.3.2: Storegga slide; height of deposits above recent sea level (Bondevik et al. 2005)
The volumes of coastal slides are smaller. Theoretical slides off the Norwegian coast were
modelled by Rubino et al. in 1998. The expected height of tsunami caused by such slides
was found to be 1-2 m, their wavelengths 10 km, and their period about 10 minutes.
A submarine slide near Newfoundland caused by an earthquake was recorded on
18 November 1929, at 20:32 UTC (Ruffmann 2005). Typical periods of the waves generated
by the slide were between 12 and 25 minutes. The resulting tsunami had amplitudes of 3-8 m
at Newfoundland and was recorded as far as Portugal. Unfortunately, all European coastal
gauge station records from those days have disappeared (Fine et al., 2005). In model
simulations, the tsunami reached the German North Sea coast after about 16 hours (Fine et
al. 2005). However, no evidence of the tsunami has been found in the original, analogue
records of the Cuxhaven gauge station (Fig. 3.3.3).