Geoscience Reference
In-Depth Information
Some seismic events (e.g. Sanriku, 1896, the Aleutian earthquake, 1946) caused
tsunamis of intensities higher, than could be expected from the available seismic
data. Kanamori [Kanamori (1972)] termed such earthquakes 'tsunami earthquakes'
and presumed them to occur, when the process at the earthquake source underwent
unusually slow development. This case is characterized by a low emission efficiency
of the high-frequency component of seismic waves, which is not so important for
the process of tsunami generation.
Figure 2.1 presents the relationship between the tsunami intensity (Soloviev-
Imamura scale) and the earthquake magnitude for the Pacific region constructed by
means of the Pacific tsunami database (see Sect. 1.5). The large spread between
the data signifies that the relationship between tsunamis and earthquakes is complex
5
4
3
2
1
0
−
1
−2
−
3
−4
−5
5
6
7
8
9
10
M
W
Fig. 2.1 Dependence of the tsunami intensity, according to the Soloviev-Imamura scale, upon
the earthquake magnitude
M
w
for the Pacific region
