Geoscience Reference
In-Depth Information
6.5 m in Japan and the USSR and 3.5 m in the USA. About 1,000 persons lost their
lives in Chile, 60 on the Hawaiian islands and 200 in Japan. It took approximately
15 h for the waves to cover 10,000 km and to reach the Hawaiian islands and
nearly a day and night to reach Japan and the Far-East coast of the USSR. Natu-
rally, the earthquake was felt neither on the Hawaiian islands, nor in Japan, nor in
the USSR, so the wave turned out to be unexpected.
The 1994 tsunami caused by an earthquake of magnitude
M
= 8.3 near the
Island Shikotan, resulted in the destruction of numerous coastal structures. Part
of the island sank by 60 cm, which was recorded by the mareograph in the vil-
lage of Malokurilsk. In the city of Yuzhno-Kurilsk, located at a distance of 120 km
from Shikotan, the tsunami wave tore down a single-storeyed block of flats from its
foundation and carried it 300 m inland. The wave's maximum run-up amounted to
10.4 m.
The 1998 tsunami that occurred in the region of Papua New Guinea gave rise to
particular interest among specialists. A relatively small earthquake of magnitude
M
w
= 7
.
1 resulted in an unexpectedly large wave of height amounting to 15 m. The
tsunami attacked the coast with three waves about 18 min after the earthquake. The
area influenced was limited to part of the coastline 30 km long, where several fish-
ing villages were destroyed and about 3,000 people lost their lives. The formation
of such a gigantic wave was mainly due to the underwater slide caused by the earth-
quake, rather than to the earthquake itself.
The catastrophic tsunami of December 26, 2004 that occurred in the Indian
Ocean was caused by an exceptionally strong earthquake of magnitude
M
w
= 9
.
3,
the epicentre of which was near the northern extremity of Island Sumatra. Compa-
rable magnitudes were exhibited during the past 100 years only by several seismic
events [Aleutian Islands, 1946; Kamchatka, 1952; Aleutian Islands, 1957; Chile,
1960; Alaska, 1964]. The manifestation of the tsunami was of a global charac-
ter. Besides the castastrophic consequences in the vicinity of the source (the coast
of Sumatra), where the run-up amounted to 35 m, waves were registered all over
the World Ocean. Tsuami waves of significant amplitudes were registered in remote
parts both of the Pacific coast (Manzanillo, Mexico—0.5 m, New Zealand—0.5 m,
Chile—0.5 m, Severo-Kurilsk, Russia—0.3 m, British Columbia, Canada—0.2 m,
San Diego, California—0.2 m) and of the Atlantic coast (Halifax—0.4 m, Atlantic
City—0.2 m, the Bermuda islands—0.1 m, San Juan, Puerto Rico—0.05 m). The
worst hit were countries of the basin of the Indian Ocean: Indonesia, Thailand, India,
Sri Lanka, Kenya, Somalia, South Africa and the Maldive Islands. The total number
of victims exceeded 250,000 people, the damage was enormous and it still has to be
estimated. The number of casualties makes this catastrophe the largest of all known
catastrophes in the history of tsunamis.
Central Kuril Islands Tsunamis. An extremely strong earthquake of magnitude
M
w
= 8
.
3 took place on November 15, 2006, in the Central-Kuril segment of
the Kuril-Kamchatka seismofocal zone. The epicentre of the earthquake was located
in the Pacific Ocean at about 85 km from the northern extremity of Simushur Island.
Before this event, the Central-Kuril segment was considered a 'seismic gap' zone,
an earthquake of such strength was registered here for the first time in the history
of seismic observations. Nearly 2 months later, on January 13, 2007, another
