Geoscience Reference
In-Depth Information
Chapter 1
General Information on Tsunami Waves,
Seaquakes and Other Catastrophic
Phenomena in the Ocean
Abstract Fundamental information on the physics and geography of tsunami waves
is presented. Examples are given of known historical events, illustrating the char-
acter of tsunami manifestation on coasts. Quantitative characteristics are introduced
that describe tsunami strength: magnitude and intensity. Physical principles of the
operation of tsunami warning systems are described. Information is provided on
tsunami catalogues and electronic databases. The seaquake phenomenon is defined,
and a synthesized description is given. Information is presented on the main hy-
droacoustic effects, related to underwater earthquakes: the T-phase, low-frequency
elastic oscillations, and cavitation. Basic information on killer waves is given.
Keywords Tsunami
·
seaquake
·
surface gravitational waves
·
long waves
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run-up
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sudden inundation
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impact of waves
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erosion
·
damage
·
fires
·
environment pollu-
tion
·
epidemics
·
human casualties
·
local tsunami
·
regional tsunami
·
teletsunami
·
tsunami catalogue
·
historical tsunami database
·
tsunami magnitude
·
tsunami in-
tensity
·
tsunami warning
·
hydroacoustic signals
·
T-phase
·
cavitation
·
freak waves
Catastrophic oceanic waves, termed 'tsunami' back in the 1960s, were considered
a mysterious and inexplicable phenomenon of the life of the ocean. The sudden
onslaught on the coast by a rabid giant wave would take the lives of tens of thou-
sands of people and leave memories engraved for a long time on the minds of those
who remained alive. Scientists of many countries have united their efforts to under-
stand the secret of this awe-inspiring phenomenon and to bring nearer resolution of
the problem of tsunami waves. At present, scientists have at their disposal the infor-
mation on 1,500 events in oceans and seas that have given rise to tsunami waves.
The Pacific is considered the most tsunami-dangerous region, in which approxi-
mately 1,300 events are known [Soloviev et al. (1974), (1975), (1986)]. About 300
tsunami events are known to have taken place in the Mediterranean Sea. There exists
information on tsunamis in the Atlantic Ocean and the Caribbean sea, in the Black
and Caspian Seas [Nikonov(1997), Dotsenko et al. (2000), Lander et al. (2002)].
Insignificant tsunamis also occurred on lake Baikal [Soloviev, Ferchev (1961)].
Europe was exposed to the action of the catastrophic tsunami of 1755, during
