Introduction - Tsunami - page 9

1.5 Distribution and Fatalities

Table 1.1 Percentage distribution of tsunami in the world's oceans

and seas
Location Percentage

Accounts of tsunami extend back almost 4000 years in
China and the Mediterranean—where the first tsunami was
described in 2000 BC in Syria—and about 1300 years in
Japan (Bryant 2005 ; Gusiakov 2008 ). However, many
important tsunamigenic regions, such as the west Pacific
Ocean, have much shorter documentation concomitant with
European colonization (Lockridge 1985 ; Lander and
Lockridge 1989 ). For example the Chile-Peru coastline,
which is an important source of Pacific-wide tsunami, has
records going back only 400 years to 1562, while those
from Alaska have only been documented since 1788. Tsu-
nami records in Hawaii, which is a sentinel for events in the
Pacific Ocean, exist only from 1813 onwards. Few records
exist along the west coast of Canada and the contiguous
United States. The southwest Pacific Ocean records are
sporadic and almost anecdotal in reliability. Only in the last
30 years have records been compiled from Australia and
New Zealand, with historical documentation extending back
no further than 150 years (de Lange and Healy 1986 ;
Australian Bureau of Meteorology 2013 ). Tsunami have
killed over 700,000 people throughout history, ranking them
fifth after earthquakes, floods, tropical cyclones and volca-
nic eruptions (Gusiakov 2008 ). Up to 8 % of all reported
historical tsunami have no identified source. Even in the
20th century, 51 events have no known source. Most of the
latter were minor events; however, six of these events had
run-ups of more than 5 m.
The regional distribution of major tsunami is tabulated in
Table 1.1 (Bryant 2005 ). Only the South Atlantic appears to
be immune from tsunami. The North Atlantic coastline also is
virtually devoid of tsunami. However, the Lisbon earthquake
of November 1, 1755, which is possibly the largest earth-
quake known, generated a 15 m high tsunami that destroyed
the port at Lisbon (Reid 1914 ). It also sent a wall of water
across the Atlantic Ocean that raised tide levels a meter above
normal in Barbados and Antigua in the West Indies. Tsunami
also ran up and down the west coast of Europe, and along the
Atlantic coast of Morocco. The Spanish port of Cádiz and
Madeira in the Azores were also hit, while a 2-3 m high wave
sunk ships along the English Channel. The continental slope
off Newfoundland, Canada, is seismically active and has
produced tsunami that have swept onto that coastline. The
Burin Peninsula Tsunami described earlier reached Boston,
where it registered a height of 0.4 m (Whelan 1994 ). By far
the most susceptible ocean to tsunami is the Pacific Ocean
region, accounting for 52.9 % of all events.
Løvholt et al. ( 2012 ) used historical records and envi-
ronmental setting to assess the vulnerability of the world's
coastline to earthquake-induced tsunami with a 10 % ex-
ceedence probability in 50 years. By including population

Atlantic East Coast 1.6

Mediterranean 10.1

Bay of Bengal 0.8

East Indies 20.3

Pacific Ocean 25.4

Japan-Russia 18.6

Pacific East Coast 8.9

Caribbean 13.8

Atlantic West Coast 0.4

Source From Bryant ( 2005 )

exposure, they were able to quantify the global tsunami
mortality risk. They found that tsunami affect 76 countries
and territories with 19 million people living in vulnerable
areas as of 2007. Indonesia and Japan account for more than
50 % of this population. However, in percentage terms, the
islands of Macao (China), New Caledonia, and Fiji have the
greatest risk with 15, 9, and 7 % of their populations
respectively being threatened. In economic terms, $186
billion dollars of revenue lies in tsunami-prone regions.
This does not include infrastructure. Japan has by far the
highest economical exposure accounting for 76.3 % of
threatened revenue. This is followed by the United States
and Canada with $12.7 billion and $3.9 billion respectively.
The greatest threat to national economies occurs in New
Caledonia, Macao (China) and the Maldives where 10.7, 9.0
and 4.3 % of GDP is at risk. The following sections
describe some of the more noted oceans or seas that have
experienced tsunami.

1.5.1 Mediterranean Sea

The Mediterranean Sea has one of the longest records of
tsunami (Kuran and Yalçiner 1993 ; Tinti and Maramai
1999 ). Over 300 events have been recorded since 1300 BC.
Large tsunami originate in the eastern Mediterranean, the
Straits of Messina of southern Italy, or southwest of Por-
tugal. About 7 % of known earthquakes in this region have
produced damaging or disastrous tsunami. Major earth-
quakes occurred in the Eastern Mediterranean in 365, 1222,
1303, 1481, 1494, 1822 and 1948. Around Greece, 30 % of
all earthquakes produce a measurable seismic wave, and 70
major tsunami have been recorded. Around Italy, there have
been 67 reliably reported tsunami over the past 2000 years.
The majority of these have occurred in the last 500 years, as
records have become more complete. Of these, 46 were
caused by earthquakes and 12 by volcanoes. By far the most