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Indian Ocean Tsunami

LOST LIVELIHOODS
ENVIROMENTAL DAMAGE
ASSESSING IMPACT AND VULNERABILITY
EARLY WARING
CHALLENGES FOR THE FUTURE

On 26 December 2004, an undersea earthquake measuring 9.0 on the Richter scale took place in the Indian Ocean, off the west coast of northern Sumatra, Indonesia.

Table1: Largest earthquakes in the world since 1900
Date
Location
Magnitude
1960
Chile
9.5
1964
Prince William Sound, Alaska
9.2
1957
Andreanof Islands, Alaska
9.1
1952
Kamchatka, Russia
9.0
2004
Indian Ocean, off the west coast of northern Sumatra
9.0
1906
Pacific Ocean off the coast of Ecuador
8.8
1965
Rat Islands, Alaska
8.7
1950
Assam, India, and Tibet, China
8.6
1923
Kamchatka, Russia
8.5
1938
Banda Sea, Indonesia
8.5
1963
Kuril Islands
8.5
Source: USGS 2005

It caused one of the deadliest disasters in recent times, as resulting tsunami waves crashed into the coastlines of twelve countries bordering the Indian Ocean, causing massive losses in human life and infrastructure, and damage to marine and terrestrial ecosystems.

This was the fourth largest earthquake in magnitude in the last hundred years (Table 1), resulting in one of the deadliest tsunamis in recent times (Table 2). Over 220 000 people in Asia were killed by the tsunami, mostly in Indonesia, Sri Lanka, India, and Thailand, with smaller numbers in East Africa (BBC 2005). As the waves moved through the Indian Ocean at over 500 km/h (UNOCHA 2005a) (Figure 1), countries as far away as those in East Africa were affected, including Small Island Developing States (SIDS) like Seychelles and Mauritius, and mainland countries like Somalia, Kenya and Tanzania. Casualties were particularly high among children and women - for instance, in India, 40 per cent of the dead were estimated to be children (UNOCHA 2004a).

More than 5 million people were displaced as houses and villages were flattened by giant waves. The province of Aceh in northern Sumatra experienced the greatest impact from waves exceeding 15 metres in height (NASA 2005). The city of Banda Aceh was severely damaged. Bridges were destroyed and ships were overturned as the waves advanced towards the surrounding foothills. In the Maldives, where 53 islands suffered severe damage and 10 per cent of the 1 200 islands and atolls were totally destroyed, approximately 12 200 people were registered as homeless, of whom 8 500 had to be evacuated to other islands (UNOCHA 2005b).

In the short term, millions of people, particularly children, face the risk of disease due to polluted water, damaged sanitation systems and crowded living conditions in camps and the remaining housing (WHO 2005). However, the impact of this disaster will be felt for decades to come. Drinking water sources such as wells and groundwater have been contaminated by saline water, and will take years to recover. Infrastructure has been severely damaged and livelihoods are critically impacted, particularly those related to fisheries, agriculture and tourism.

 

Figure 1: Simulations of the Indian Ocean tsunami, using the Method of Splitting Tsunami (MOST) model

Source: NOAA 2004a


Table 2: Major tsunamis worldwide

Date
Origin*
Effects
Death Toll
1692 Puerto Rico, Caribbean Port Royal, Jamaica permanently submerged
200
1755 Atlantic Ocean

Lisbon destroyed

60 000
1835
Peru -Chile Trench
Concepción, Chile destroyed
not available
1868
Peru -Chile Trench
Town of Arrica destroyed
10 000-15 000
1883
Krakatoa (volcanic eruption)
Devastation in East Indies
36 000
1896
Japan Trench
Swept the east coast of Japan with waves of 30.5m at Yoshihimama
27 122
1908
Sicily

East of Sicily, including Messina and toe of Italy badlydamaged

58 000 (including earthquake victims)
1933
Japan Trench
9 000 houses and 8 000 ships destroyed, Sanriku district, Honshu
3 000
1946
Aleutian Trench
Damage to Alaska and Hawaii
159
1960
South-Central Chile
Coinciding with a week of earthquakes. Damage to Chile and Hawaii
1 500
1964
Anchorage, Alaska
Severe damage to south coast of Alaska
115
1976
Celebes Sea
Devastation in Alicia, Pagadian, Cotabato and Davao, Philippines
8 000
1998
Papua New Guinea, Bismarck Sea
Devastation in Arop, Warapu, Sissano and Malol, Papua New Guinea
2 200
2004
Papua New Guinea, Bismarck Sea
11 countries affected across 2 continents
220 000

* Earthquake, unless otherwise specified
Source: NOAA 2004b

 


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