[Solved] On December 2004, tsumani brought havoc on 14 countries including India. Discuss the factors responsible for occurrence of Tsunami and its effects on life and economy. In the light of guidelines of NDMA (2010) describe the mechanisms for preparedness to reduce the risk during such events ( UPSC GS-3 Mains 2017)
A tsunami is a series of large waves generated by an abrupt movement on the ocean floor that can result from an earthquake, an underwater landslide, a volcanic eruption or – very rarely – a large meteorite strike. The factors responsible for tsunami are:
• Earthquakes: Most tsunami are caused by large earthquakes on the sea floor when slabs of rock move past each other suddenly, causing the overlying water to move. The resulting waves move away from the source of the earthquake event. The 2004 tsunami occurred along a thrust fault in the subduction zone where the Indian tectonic plate is going below the overriding Burmese plate. As a result, the ocean floor broke and there was a vertical displacement of about 15 to 20 meters along the fault causing large scale displacement of water and thus, generating tsunami waves. This kind of large vertical displacement happened because the magnitude of the earthquake was greater than 9 and it occurred at a shallow depth of less than 30km below the ocean.
• Landslides: Underwater landslides can cause tsunami as can terrestrial land which slumps into the ocean.
• Volcanic eruptions: These occur in several ways: a) destructive collapse of coastal, island and underwater volcanoes which result in massive landslides b) pyroclastic flows, which are dense mixtures of hot blocks, pumice, ash and gas, plunging down volcanic slopes into the ocean and pushing water outwards c) a caldera volcano collapsing after an eruption causing overlying water to drop suddenly.
Effect on human beings
• One of the biggest and worst effects of a tsunami is the cost to human life because unfortunately escaping a tsunami is nearly impossible. Hundreds and thousands of people are killed by tsunamis.
• People living in coastal regions, towns and villages have no time to escape. The violent force of the tsunami results in instant death, most commonly by drowning. Buildings collapsing, electrocution, and explosions from gas, damaged tanks and floating debris are another cause of death. The tsunami of December 2004 that struck South East Asia and East Africa killed over 31, 000 people in Sri Lanka only, leaving 23, 000 injured.
• Tsunami waves and the receding water are very destructive to structures in the run-up zone. The areas close to the coast are flooded with sea water, damaging the infrastructure such as sewage and fresh water supplies for drinking.
• Flooding and contamination of drinking water can cause disease to spread in the tsunami hit areas.
Illnesses such as malaria arise when water is stagnant and contaminated. Under these conditions it is difficult for people to stay healthy and for diseases to be treated, so infections and illnesses can spread very quickly, causing more death.
• Tsunamis not only destroy human life, but have a devastating effect on insects, animals, plants, and natural resources.
Damage to economy
• Daily life for individuals in a nation affected by tsunami is altered by the damage the disaster can cause to the economy. Locations that were previously popular destinations for tourists suffer depression as a result of lost tourism, with visitors staying away out of fear and during reconstruction.
• Rebuilding after a tsunami puts a significant financial strain on governments as well, resulting in an economic downturn that can affect entire regions of the world.
• Also after a tsunami, work buildings are destroyed, this means that everyone loses their job or has to wait months, years for their work to build up again. If the city decides not to build the work space up again, thousands of people have to find new jobs. If people can’t find new jobs, they won’t have any money for a house food or water. This would mean that the society rate would decrees. Because people will be suffering from starvation or from dehydration.
The 2004 tsunami also prompted NDMA to formulate Tsunami Risk Management Guidelines to outline inter-agency roles and responsibilities, tsunami risk preparedness, mitigation and response.
• The Guidelines recommends practical and effective ways for awareness generation, capacity building, education, training and research & development for better tsunami risk management.
• The Guidelines explore options for effective dissemination of tsunami alert and warning messages generated by INCOIS to the concerned agencies and coastal vulnerable communities exposed to tsunamis in a coordinated manner.
• Structural Mitigation measures, as envisaged in the Guidelines, gives a brief guidance on design and construction of new structures as well as strategies for protecting lifeline and priority structures from Tsunamis along the seafront.
• The Guidelines urge BIS to roll out the pending construction standards entitled ‘Criteria for TsunamiResistant Design of Structures’. It further recommends a robust techno-legal regime through efficient land use practices, bio shields, shelter belt plantation and mangrove regeneration with community involvement.
Factors responsible for Tsunami are:
- 1.Earth quake under oceans
- 2.Oceanic volcanic erruption
- 3.Under water nuclear tests
- Once the tsunami occur entire costal areas will become like a deluge. All communication networks including electricity supply also effected . People lost their shelter, food grains are coplerle submerged under water, no cloaths , all developmental projects , industries, various strategic installments get damaged. Economic activities in that area will be stalled , we need to spend lot of amount on reconstruction activities. Mean while health related problems also aggravate the severity of the problem.transportation network also damaged which is life line of economy. Loss of life , mental trauma , social order get disturbed.
- Under the NMDA guidelines prepared ness include
- Early warning system : By arranging the radars in coastal areas , so that it can detect the shock wave few minutes prior the tides reached the coastal area.
- Develop a faster comminication system(to decippate the information pertaining to regular alerts) 3. Preparedness of NDRF and other related forces
- Preparedness of health,food,roads etc (PWD) departments 5. Amature comminication system , which works without power and support of regular communication system, is to be developed 6. Early preparation of the community through mock drills 7. Arrange mental trauma care centres
- 8. Avoid construction of houses in occupied ,low level water body areas.
- Tsunamis are massive waves which are caused by either volcanic or seismic activity in deep ocean which displaces water. The waves on reaching shallow waters gain a height of several metres and cause maximum damage to life and property. Factors which cause Tsunami are as follows: Seismic activity under ocean: Earthquakes under the ocean primarily in subduction zone caused an oceanic plate to be forced down into the mantle by tectonic forces. This leads to abrupt and huge deformation of the ocean floor. This huge energy further gets transferred to water which surges and causes huge damage.
- Landslides: Submarine landslides releases a gigantic amount of energy at a rate which is not absorbed by the water completely. This causes the tsunami.
- Volcanic eruptions: Sudden displacement of water caused by a volcano, slope failure of a volcano or even a phreatomagmatic explosion and collapse causes huge waves resulting in a tsunami.
- Deep depressions: These are caused by low atmospheric pressures and winds which gain potential to lift water and make it move with the cyclone.
- Many other factors like nuclear tests, glacial convulsions etc. also have the potential to cause a tsunami.
- Tsunamis cause tremendous loss of life, property, vegetation, trees, environment etc. The tsunamis cause heavy economic damage to seaside towns and beaches which heavily rely on tourism. Governments come under an obvious financial strain which can also result in a full-swing economic downturn. People have to rebuild their lives and livelihoods around the altered region.
- NDMA has proposed many Guidelines (2010), for preparedness to reduce the risk of Tsunamis by recognition of major gaps in the same.
Preparation of Tsunami Vulnerability Assessment and increasing public awareness in coastal areas on the subject is critical to reducing risk. Moreover, enforcement and complete compliance with town-planning by-laws is another crucial factor in mitigating the risk. Along with these a number of tsunami early warning systems like a Network of Land-based Seismic Stations, setting up of National Early Warning Centre etc. has been taken up in addition to capacity-building, training and education of all stakeholders.
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