Geoscience Reference
In-Depth Information
earthquake of practically the same strength,
M
w
= 8
.
1, occurred in the same region.
Both seismic events were accompanied by tsunami waves, noted over the entire
area of the Pacific Ocean: Shikotan Isl., Malokurilsk—1.55(0.72) m, Kunashir
Isl., Yuzhno-Kurilsk—0.55(0.11) m, Alaska, Shemya—0.93(0.69) m, Crescent
City, California—1.77(0.51) m, Hawaii, Kahului—1.61(0.24) m, Peru, Callao—
0.73(0.3) m, Chile, Talcahuano—0.96(0.23) m (the wave heights indicated in
brackets correspond to the event of January 13, 2007). However, owing to the ab-
sence of mareographic stations and inhabitants on the Central Kuril Islands, no in-
formation on the wave heights in the immediate vicinity of the sources was available.
During the period from July 1 to August 14, 2007, two seafaring expeditions were
organized with one of their main tasks consisting in the investigation of the coasts
of the islands so as to determine the tsunami run-up heights [Levin et al. (2008)].
The participants of the expedition were the first people to visit the islands after
the tsunamis and to estimate the scale of the natural disaster. The time for the ex-
pedition depended on the complicated weather conditions in the area. Landing
on the coasts of the islands earlier (before April-May) was practically impossi-
ble to realize. The highest tsunami run-ups (up to 20 m) were revealed on Matua
Island. The tsunami strongly altered the morphology of the coast in the Ainu Bay
(south-west of Matua Island) by washing away a section of the sea terrace 20-30 m
wide. The maximum run-up height in Dushnaya Bay (north-east part of Simushir
Island) amounted to 19 m; here the tsunami left numerous scours. Besides erosion
on the coasts investigated, accumulation was also observed everywhere. Tsunami
deposits consisted of marine sand, pebbles, boulders and floating debris shifted
toward the land. The vegetation on steep slopes was partly destroyed, and the soil
washed away. If waves of such strength were to hit a densely populated coast, casu-
alties could certainly not be avoided. The only reason the tsunamis of November 15,
2006, and of January 13, 2007, did not become an awful tragedy was the total ab-
sence of population on the Central Kuril Islands. These two events can rightfully be
considered the strongest tsunamis that were not accompanied by human casualties.
Table 1.1 presents several examples of recent catastrophic tsunamis.
Table 1.1 Recent catastrophic tsunamis
No
M
a
h
b
max
Date
Number of
Location of event
(m)
casualties
1,000
c
1
12/12/1992
7.5
26
Flores Is., Indonesia
330
c
2
12/07/1993
7.7
31
Okushiri Is., Japan
3
02/06/1994
7.8
14
223
Java, Indonesia
11
c
4
04/10/1994
8.1
10
Shikotan Is., Russia
5
09/10/1995
8.0
11
1
Manzanillo, Mexico
6
17/02/1996
8.1
7.7
110
Irian Jaya, Indonesia
7
17/07/1998
7.1
15
2,200
Papua New Guinea
8
23/06/2001
8.1
10
26
Peru
250,000
c
9
26/12/2004
9.3
36
Indian Ocean, Sumatra
10
15/11/2006
8.3
20
0
Central Kuril Is., Russia
a
Earthquake magnitude
b
Maximum wave height
