Geoscience Reference
In-Depth Information
2. A change in the sea surface temperature (the formation of an SST anomaly), to
which the atmosphere should react, i.e. weather anomalies can also be expected.
Since, as a rule, the temperature of the water decreases, as the depth increases,
the formation of precisely cold SST anomalies is to be expected, in most cases.
3. Transfer of biogenes up to the surface layer, usually impoverished of these sub-
stances, and, as a consequence—similar to what happens in upwelling zones,
a short-lived, but noticeable enhancement in the concentration of phytoplank-
ton (certain species are capable of reproducing at a rate of 2-3 multiplications
per day). Taking into account that the phytoplankton, being the primary link in
the trophic chain, determines the bioproductivity of water, the migration of fish
and sea animals is possible.
4. Evolution of the zone of violated and, therefore, unstable stratification should
create a powerful system of internal waves with amplitudes many times greater
than the amplitude of internal tsunami waves that is comparable to the residual
bottom displacement.
The fourth consequence can hardly be reflected in testimonies by witnesses—its
registration requires special instrumentation; therefore, in dealing with the first three
of the above consequences, and having become acquainted with the descriptions of
events, we consider it appropriate to single out the four following groups of features
that point to possible intensification of vertical exchange in the ocean, resulting from
an underwater earthquake:
1. Unusual agitation, rough behaviour of the sea, 'boiling' water and so on
2. The appearance of fish (dead, deep-water, unusual) or of sea 'monsters', a de-
crease (increase) in the fish catch, etc.
3. Weather phenomena (change of wind, fog, rain, hail etc.)
4. Change in colour of the sea, the water becomes turbid
We shall present some excerpts from the descriptions of those events, that are char-
acterized by at least one of the indicated features.
The Mediterranean sea
1.
79, August 24(23), 7 h. Tyrrhenian Sea, Bay of Naples.
40
.
48
◦
N, 14
◦
27
E.
The next day after the powerful eruption of the volcano Vesuvius a strong earth-
quake occurred with its source, possibly, in the Bay of Naples. In a letter to the his-
torian Tacitus, the writer Pliny the Elder, an eyewitness of the events, mentioned
that 'the sea was violent and hostile'.
2.
551, spring or July 7. Aegean Sea. Eastern Greece, Strait of Euboea (between
the Island of Euboea and the continent).
38
.
4
◦
N, 22
.
3
◦
E.
A destructive earthquake that embraced both coasts of the Gulf of Corinth.
A tsunami. After the water went away, fish, including rare species, were left
stranded.
3.
1202 (possibly, 1222) May 22, morning (at sunrise). Levantian Sea, Middle
East.
A destructive earthquake in Palestine with its source, possibly, near Nablus,
where no single wall remained intact. Near the coast of Syria, after the earthquake,
the water in the sea opened up slightly in various places and was divided into hill-
like masses
...
a great number of fish were thrown out onto the shore.
