Geoscience Reference
In-Depth Information
The tsunami reduced the site, where the city of Arica with about 5,000 inhabitants
had been, to a smooth sandy valley without any signs of buildings. Only individual
structures remained here and there on the mountain slopes.
The catastrophic 1908 Messina tsunami was caused by an earthquake of mag-
nitude 7, the source of which was located under the bottom of the Messina Strait
(in between continental Italy and Sicily). The tsunami started nearly immediately
after the shaking stopped with a withdrawal of the sea water. Part of the sea-floor,
adjacent to the coast, happened to be drained, in some places the sea-floor opened
up for nearly 200 m. Then, all of a sudden, waves started to advance, the first three
being the strongest. The tsunami was preceded by a strong noise, similar to the noise
of a tempest or of waves hitting rocks with force. The maximum run-up height on
the coast of Sicily amounted to 11.7 m, on the Calabrian coast to 10.6 m. Noticeable
waves reached the coasts of Libya and Egypt. Of the mareographs that were not
damaged, the one closest to the tsunami source was located on the Malta island. It
recorded a tsunami of amplitude 0.9 m.
The number of tsunami waves observed varied from place to place from 3
to 9, and the period of the waves from 5 to 15 min. The waves washed out the
structures destroyed by the earthquake and destroyed many buildings that had sur-
vived. Of the buildings and structures only the foundations, sliced off at land level,
remained.
Many vessels, having been damaged, either sank or were stranded inland.
The tsunami stirred up sea-floor sediments; bubbles of gas came up from the sea-
floor to the surface of the strait; sea animals and fish, including deep-water
inhabitants, unknown to fishermen, were thrown up onto the beach. Sailors on
vessels moored several miles from the coast felt a strong seaquake, but couldn't
understand why all the lights had gone out in the towns along the coast.
After the tsunami all the strait was full of broken and overturned boats, other
vessels, floating debris, bodies of human beings and animals, washed off the coasts
of Messina and Calabria.
The 1952 tsunami that occurred near the eastern coasts of Kamchatka and of the
Island of Paramushir is considered one of the most destructive tsunamis of the twen-
tieth century. We shall present the description of this event given in the article by
S. Soloviev [Soloviev (1968)]. In the night between November 4 and 5 the inhabi-
tants of Severo-Kurilsk were woken up by an earthquake: stoves were destroyed,
chimneys and household utensils fell down. Forty minutes after the earthquake
stopped a rumble was heard from the ocean, and a water bore moving with a high
velocity fell upon the city. In several minutes the water retreated, carrying away
what it had destroyed, and the ocean bottom opened up for several hundred me-
ters. In 15-20 min a wall of water 10 m high once again advanced upon the city.
It practically washed away everything in its way, at the most leaving only concrete
foundations of various structures. Old pillboxes were wrenched out of the ground
and thrown around, in the harbour the walls of a bucket were turned upside down,
and launches that happened to be there were stranded hundreds of meters inland.
Several minutes later, after this strongest wave, a third relatively weak wave ran
up the devastated coast, leaving much debris after it.
