The December 26, 2004 Indian Ocean tsunami, triggered by a massive earthquake off the coast of Sumatra, is the deadliest natural disaster ever of this kind. Aside from a massive number of casualties, this tsunami caused heavy economic damage and severe destruction to the natural environment of stricken countries. Given the significant destruction and suffering, it resulted in massive international support through financial and humanitarian aid. The purpose of this paper is to provide an analysis and a better understanding of the causes, the impacts and actions that could have been taken to limit the damage.
The December 26 2004 Indian Ocean Tsunami ranks among the ten deadliest natural disasters ever recorded thus far with a death toll over 225 000 and thousands of individuals missing. The large tsunami waves were generated by a massive earthquake off the northwest coast of Sumatra Island in Indonesia (Rossetto 2007). Tsunami waves spread across the Indian Ocean, damaging the shores of countries near and far from the epicenter (Rossetto 2007). It produced considerable damage and its impact went beyond the toll of human casualties. It had widespread economical, environmental and psychological impacts. Among the worst hit regions were the countries in and around the eastern Indian Ocean. Such natural disaster causes tremendous human suffering and immediately solicited responses worldwide with significant financial support and humanitarian aid.
Sequences of Events (Earthquake & Tsunami)
The 9.0 magnitude earthquake of 26 December 2004 that occurred off the northwest coast of Sumatra in Indonesia was the third largest earthquake ever recorded. With an epicenter located near the Indonesian island of Sumatra, the quake was generated as a result of the sliding of a portion of the India plate beneath the Burma plate (Risk Management Solution, 2006). The result was a fault rupture, displacing the seafloor (Figure 1) and a large volume of the ocean, triggering devastating waves that hit the coastline of 11 Indian Ocean countries (Bilham 2005). The tsunami waves travelled across the Indian Ocean with an average velocity of 640 km/h (Rossetto 2007).
However, tsunami waves tend to behave differently in deep water than in shallow water (Rossetto 2007). Once the tsunami reaches shallow water along the coastline, the wave velocity decreases while its amplitude increases significantly from the mass amount of energy built by the wave, causing even more destructive waves and substantial inland inundation (Rossetto 2007). In Aceh, north of the island of Sumatra, wave height reached 24 meters once it hit the shores and rose up to 30 meters inland, with a maximum wave height recorded to be 60 meters (Paris 2007).
Being the landmass closest to the epicenter of the earthquake, Aceh province was the hardest hit area from the eastward-moving tsunami followed by Sri Lanka because of non-existing landmass between it and the epicenter of the quake to protect the coastlines (Athykorala 2005). The fault rupture of the earthquake was in a north-south orientation, which meant that the strength of the tsunami was greatest in east-west direction (Athykorala 2005). Hence, despite being located near the epicenter, some regions escaped the worst from the tsunami given their position relative to the fault rupture.
With this said, Somalia was hit harder than Bangladesh despite being farther away from the epicenter (Athykorala 2005). Depending on the distances involved, the tsunami could propagate up to hours before reaching some coastlines. Aceh, Nicobar and Andaman were among the first regions to feel the effect of the tsunami, eventually hitting coastal regions of Thailand, Myanmar, India, Sri Lanka, Maldives, Somalia, Kenya and Tanzania (Figure 2). At last, its effects were also detected along the west coast of North and South America, which includes Vancouver and British Columbia.
A tsunami is produced by a sudden vertical shift of the seafloor causing a displacement of a massive volume of water, usually an ocean. Depending on the size of the sea floor displacement, it will have a different impact on wave formation from the surface water. These displacements can be a result of underwater disturbances such as earthquake, volcanic eruption, meteorite impact and landslide (National Geographic). As for the 2004 Indian Ocean tsunami, a 9.0 magnitude earthquake triggered it and caused an estimated 1600 km of fault line slipped about 15 meters along the zone where the Indian plate subducts beneath the Burma plate (Rossetto 2007). As the northern rupture continued, it transformed from a subduction (Figure 3) to a strike-slip fault; two plates slide pass one another in opposite direction. With this said, displacement caused by this earthquake generated a tsunami that ranks among the deadliest natural disasters ever occurred.
Beyond the heavy toll of human lives, the Indian Ocean Tsunami has caused severe economical, environmental and psychological consequences, which will affect the regions for upcoming years. With 174 500 casualties, 51 000 missing and roughly 1.5 million displaced, the toll of human casualties from this tsunami has no modern historical equal (Risk Management Solution 2006). Among the countries hit by the tsunami, Indonesia, Sri Lanka, Thailand and India were left with the most serious damage and death tolls. The aftermath of the tsunami was even worse than anticipated with deaths recorded as far as 8000 km away from the epicenter, along the east coast of Africa.
Thousands of individuals were carried away by the waves into the open sea and the ones who survived were left with no food or clean water and open wounds (National Geographic 2005). Given a high risk of famine and epidemic diseases, the level of death increased significantly (National Geographic 2005). With this said, given the extent of the disaster, it instantly spurred international support and assistance through financial and humanitarian aid for the people affected by the tsunami (National Geographic 2005) A humanitarian campaign was quickly put in place to provide temporary sanitation facilities, nutrition and fresh water to contain the spread of diseases (National Geographic 2005).
The main economic impacts of the Indian Ocean Tsunami were the damage inflicted to the fishing and tourism industry. As a result of the tsunami, marine fishery and aquaculture harvests of affected nations were severely depressed (UKabc 2006). This was in part due to lack of fishing stocks, but also damage to necessary equipment such as fishing boats and gear (UKabc 2006). As a major economic activity and a provider of foreign exchange income, fishing also provided employment to a large span of individuals. This disaster lead to high income loss for coastal fishing communities that relied heavily on fishing seasons as their primary source of income.
In addition, water surges and flooding (Figure 4) destroyed many important buildings and properties along the coasted cities that were affected, including touristic resorts (Risk Management Solution 2006). Although, most tourist infrastructures remained intact following the tsunami, tourism industry faced numerous cancellations (Rossetto 2007). Thus, the loss suffered by the fishing and tourism sector will have long-lasting economic consequences for these coastal regions.
The tsunami impacts on the environment were both widespread and destructive (Figure 5). The main effect on the natural environment includes critical damage inflicted on the ecosystems from the salt-contamination of freshwater supplies and soil (Athykorala 2005). Seawater contaminated wells and invaded porous rocks on which stricken communities depended for water (Rossetto 2007). Hence, unless seawater can easily be pumped out, these communities were likely to depend on outside aid for water and food for upcoming months. In addition, an increased salt concentration in the soil will have a damaging effect on plants causing them to wilt and die (Athykorala 2005). As a result, some plantation sites were completely destroyed and would take several years before full recovery.
This tsunami can have an immediate devastating impact on the psychological and social well being of individuals exposed to it. Such disaster results in tremendous destruction, but also creates concern for mental health of the survivors. There was great concern over the youngsters because children and adolescents are considered to be more vulnerable than adults to such traumatic events (Bhushan 2007). Within the first 6 months following it, 23-30% of children were diagnosed with full and persistent symptoms of post-traumatic stress disorders (Bhushan 2007). This can impede with their psychological functioning, which is critical for their future development.
Although the tsunami could not be prevented, its impact could have been mitigated. Unlike earthquakes, tsunamis can be detected in advance from a Tsunami Warning System that uses a network of ocean-floor and surface sensors (Sausmarez 2005). However, such warning system did not exist in the Indian Ocean back in 2004, which left individuals of affected nations completely surprised by the tsunami (Sausmarez 2005). No effective communication infrastructure was available to warn population on the coastlines.
Following this natural disaster, an important issue arises about the population’s education of warning signs and precautions that can be taken to reduce the likelihood of death during a tsunami. For instance, if individuals had a better understanding of tsunamis, it could have saved thousands of lives. For example, they should be able to recognize that a receding sea is an indication of impending danger (Athykorala 2005). With this said, improving public awareness could be beneficial in that it prepares them to react accordingly to protect their lives and lives of others.
At a United Nations conference in 2005, an agreement was made upon establishing a Tsunami Warning System in the Indian Ocean (Sausmarez 2005). This system of warnings has been active since 2006 (Unescopress 2006).
The 26th December 2004 Indian Ocean Tsunami ranks as the most devastating tsunami ever with over 225 000 deaths. Concerns resulting from this tsunami include damage inflicted on the natural environment, vegetation, buildings and other man-made structures, but more importantly on life. Although this event caused large economic and social consequences, it led to inevitable improvement and development of measures to reduce risk of life and economic losses.
For instance, in order to reduce the vulnerability of individuals and properties on exposed coastlines, a warning system has been implemented in the Indian Ocean and will lead to improved communication in such situation. In addition, a lack of knowledge, preparedness and mitigation strategies also justifies the significant death tolls. Thus, program of mitigation and preparedness should be put into place in order to educate individuals to better cope when facing such a disaster. Finally, given that this tsunami has a return period of longer than 500 years; it is unlikely that a natural disaster of this magnitude will occur in the near future. Nevertheless, if it were to happen, these nations have the necessary protective measures to cope.
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