Geoscience Reference
In-Depth Information
The following possible mechanisms for killer-wave formation have been pro-
posed: linear, or with account of non-linear corrections, focusing of wave groups
resulting from the influence of dispersion; variable conditions of wave propagation
(variable bathymetry, variation of direction and the capture by currents); the action
of variable atmospheric conditions; non-linear modulatory instability and interac-
tion of solitonlike wave groups.
Killer waves have been repeatedly observed at the eastern coasts of Africa, where
the combination of hydrophysical peculiarities of the narrow shelf zone and a strong
wind influence provide favourable conditions for the rise of such waves. Recently,
such waves have been registered quite often at the coasts of the Atlantic, of the North
Sea and in the deep part of large water basins. The 'Newyear wave', registered on an
oil rig in the North Sea on January 1, 1995, has become a popular object of research.
We here present a description of the killer wave that originated in the Black
Sea on November 22, 2001. A 'Directional Waverider Buoy', made by the Dutch
company DATAWELL, was established in 1996 in the vicinity of the town of
Gelenjik. The Buoy was intended for direct measurement of parameters of the wind
waves (including the direction of propagation), for initial data processing and trans-
mission of the accumulated material to the coastal receiving device. The coordi-
nates of the point where the buoy was established were: 44
◦
30
40 N, 37
◦
58
70 E,
and the depth of the site was 85 m.
During the entire period of instrumental measurements of the wind waves, caused
by wind in the north-eastern part of the Black Sea (1996-2003), three records were
revealed with anomalously large waves. The record of displacements of the surface
with time, registered by the buoy on November 22, 2001, including a wave of
anomalous height, 10.3 m and a significant height of waves amounting to 2.6 m over
the set, is presented in Fig. 1.8.
Fig. 1.8 Anomalous wave, registered in the Black Sea on November 22, 2001
