indian ocean tsunami case study

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Indian Ocean Tsunami: A Case Study by Wenqi Lu

Wenqi Lu presents the facts of the 2004 Indian Ocean Tsunami in this case study.  In the morning of Dec 26th, 2004, a 9.1 magnitude earthquake shook the Indian Ocean, causing an 800 miles rupture in the ocean.  Within 20 minutes Indonesia was the first country to be impacted, and eventually, the resulting damages spanned 14 countries. The total death count reached 227,898 people, with 1,740,000 people displaced, costing countries $15 billion to rebuild and recover.

From an epidemiological aspect, 3 countries (Indonesia, Sri Lanka, and India) suffered the greatest losses in lives.  Females had a significantly higher documented mortality rate than males, with twenty-year-old males having the lowest rates.  The association between distance from the coast, gender, and mortality rates was described by Wenqi Lu.  The data used in this case study was aggregated by the Synthesis Report, and documented by the survey “Mortality, The Family and the Indian Ocean Tsunami”.

The global response to this disaster was unprecedented; in just a few hours food supplies, financial aid, and resources were rapidly deployed as well as long-term assistance to rebuild and reconstruct the affected areas.  While almost half of the health clinics were damaged, the global community was able to set up mobile field hospitals and provided the necessary relief services.

From the event, lessons learned included the gaps in the warning systems and other mitigation plans, which have been adopted during the 2012 Japan earthquake and tsunami.

Read Wenqi Lu’s case study here

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The Indian Ocean Tsunami, ​December 26th 2004 ​Case Study

How it was caused.

• The Indo-Australian Plate slid below the Eurasian Plate.
• According to the US Geological Survey it measured 9.1 on the Richter Scale. 

Effects of the Tsunami

• Estimates suggested more than 220,000 people died, 650,000 were seriously injured and up to 2 million made homeless.
• Public buildings including schools and hospitals were wiped out in some areas.
• Many people posted photos in affected areas in vain hope that a loved one had survived.
• Emergency teams and rescue services were swamped by the scale of the disaster.
• Injured people were left untreated for days as wounds turned gangrenous and conditions worsened.
• Bodies littered the streets before being buried in mass graves.
• Wide stretch of eastern and southern coastline devastated by massive waves.
• Districts of Mutur and Trincomalee inundated by waves as high as 6m.
• Port of the capital, Colombo shut by flash floods.
• High waves and floods inundate islands.
• Two-third of low-lying capital, Male, under water. 
• Province of Aceh on northern tip of Sumatra island badly hit, including provincial capital Banda Aceh, where 1,500 settlements were believed to have been wiped out.
• Dozens of buildings destroyed in the initial earthquake before flood waters washed over the region.
• People reported to have been swept away from beaches near the northern city of Penang.
• Western coast of southern Thailand badly affected included Phuket and Phi Phi island.
• Large areas of eastern coast swamped by waves.
• Deaths reported in Andaman and Nicobar Islands and Kerala State.

Immediate Responses

• Fresh water, water purification tablets, food, sheeting and tents poured in aid.
• Medical teams and forensic scientists arrived.
• The UK government promised £75 million and public donations of £100 million followed.

Long-Term Responses

• A year later £372 million had been donated by the British public, but only £128 million had been spent by the Disasters Emergency Committee (DEC) - there were organisational issues following the collection of such a large sum of money.
• Rebuilding is progressing, and the DEC has spent more than £40 million on projects in Sri Lanka and Indonesia, and plans were made to spend a further £190 million the following year building 20,000 houses.
• The Indian Ocean Tsunami Warning System was set up in June 2006, as before there had been no early-warning system.
• Ensuring people know how to respond, and that local authorities have plans in place are essential to its success.  

Global environmental hazards Case study

Understanding why natural hazards occur can help countries to manage or prevent their consequences. Case studies illustrate the impact of natural hazards in the short and long term.

Indian Ocean Tsunami 2004

A very common case study for earthquakes is the South-East Asian tsunami of 2004. Other case studies include Mexico 1985, San Francisco 1989, Kobe 1995 and Pakistan 2005.

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The causes and effects of the 2004 Asian tsunami

The underlying causes

On 26 December 2004 there was a massive and sudden movement of the Earth’s crust under the Indian Ocean. This earthquake was recorded at magnitude close magnitude The size or severity of something. For example, an earthquake. 9 on the Richter Scale close Richter scale The measure by which the strength of earthquakes is determined. and as it happened under the ocean, caused a devastating sea wave called a tsunami.

The epicentre close epicentre The point on the Earth's surface directly above the focus of an earthquake. of the earthquake occurred 200 kilometres west of the island of Sumatra in the Indian Ocean. The earthquake itself was caused by the subduction close subduction When one crustal plate is forced beneath the other. of the Indo-Australian plate under the Eurasian plate.

As the Indian plate (part of the Indo-Australian plate) moved underneath the Burma plate (part of the Eurasian plate) the crustal rocks stuck as they moved past one another. At 08:00 local time, the pressure build up was too great and the crustal rocks snapped, causing an earthquake.

When this happened the sea floor close sea floor The bottom of the ocean. was pushed upwards displacing a huge volume of water and creating the devastating tsunami waves.

Impact on landscape and population

• Some smaller islands in the Indian Ocean were completely destroyed.
• Coastal buildings were completely destroyed making people homeless.
• Fishing villages close fishing villages A small settlement where the main activity is catching fish. were completely destroyed.
• Lines of communication close lines of communication This refers to telephone cables and electricity power lines as well as roads and railways. , including phone lines, were cut off.
• Electricity power lines were cut off.
• Roads and railways were destroyed.
• Fires broke out due to severed water pipes.
• Approximately 250,000 people are estimated to have been killed, including many tourists close tourist Someone who travels for recreation or business purposes. on the beaches of Thailand.
• There was an outbreak of diseases such as cholera due to a lack of fresh water supplies.
• There was a lack of food as many fish died and farms were destroyed.
• Thousands of people were made homeless.
• Thousands of people lost their jobs as tourist hotels in Thailand were destroyed and fishing vessels were washed ashore.

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• Original Article
• Published: 08 October 2022

Finite Element Modeling of Tsunami-induced Water Levels and Associated Inundation Extent: A Case Study of the 26 th December 2004 Indian Ocean Tsunami

• P. L. N. Murty 1 ,
• Siva Srinivas Kolukula 1 ,
• E. Pattabhi Ramarao 1 &
• T. Srinivasa Kumar 1  

Journal of the Geological Society of India volume  98 ,  pages 1356–1364 ( 2022 ) Cite this article

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In recorded history, the tsunami due to the Great Sumatra earthquake of 26 th December 2004 has been the most devastating, causing the loss of over 230,000 lives besides extensive damage to most of the coastal provinces bordering the Indian Ocean. Realtime prediction of tsunami wave heights and resultant inundation of inland coastal areas are essential to safeguard the life and property of the coastal community. In the present work, a finite-element-based ADvanced CIRCulation (ADCIRC) model (widely used for storm surge simulations) is used to compute tsunami wave height and associated coastal inundation due to the 2004 event. The prime focus is on the Cuddalore coast along the east coast of India, which was heavily affected due to the tsunami. A grid resolution of around 50 m was used in the Cuddalore region to simulate the inundation in the area. Computed results are validated against the available observations. It is noticed that the model computations are in good agreement with the observations. Simulation results depict that because of its computational efficiency and accuracy, the ADCIRC can be used for near realtime prediction across the tsunami warning centers.

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Acknowledgments

The authors would like to thank the development team of the ADCIRC model. The authors also like to thank their colleagues, Mr. Patanjali Kumar, Mr. R.S. Mahendra, and Mr. Ajay Kumar, for providing the necessary data. The present article is INCOIS contribution 470.

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INCOIS: ESSO- Indian National Centre for Ocean Information Services, Hyderabad, 500 090, India

P. L. N. Murty, Siva Srinivas Kolukula, E. Pattabhi Ramarao & T. Srinivasa Kumar

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Murty, P.L.N., Kolukula, S.S., Ramarao, E.P. et al. Finite Element Modeling of Tsunami-induced Water Levels and Associated Inundation Extent: A Case Study of the 26 th December 2004 Indian Ocean Tsunami. J Geol Soc India 98 , 1356–1364 (2022). https://doi.org/10.1007/s12594-022-2183-y

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Received : 04 February 2022

Accepted : 20 April 2022

Published : 08 October 2022

Issue Date : October 2022

DOI : https://doi.org/10.1007/s12594-022-2183-y

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Case Study: Sumatra and Thailand and the 2004 Tsunami

The Importance of Tsunami Warning Systems and the challenges of warning communication.

Think back to the video you watched in Module 7 – which included scenes of the 2004 tsunami event in Indonesia. The beginning of the video focused on the Banda Aceh area of Sumatra, where fishing communities and small coastal cities were completely destroyed, and the end of the video featured the Phuket area, where more tourist beaches were affected.

Through your reading and watching the videos, you hopefully gained an idea of what it is like to be caught in a tsunami with no advanced warning, and how frantic the attempts to get out of the way must be. Imagine what it would be like to try to move small children, sick or elderly people out of the way of a tsunami with before the wave strikes and with no time to spare!

In Module 7, the events in Phuket, Thailand, are described, with tourists enjoying their vacation on the beach at Christmas 2004. Many are oblivious to the dangers of the approaching tsunami. What could have been done differently? If this were to happen again, would these communities be better informed and prepared?

In Module 7 we also mentioned that early warning systems are very tricky because of the challenges of getting the message out soon enough after the earthquake and before the tsunami waves arrive at a particular shoreline. For example, the towns on the west coast of Sumatra are so close to the Andaman fault that they had almost no time to react, so a warning may not have worked, regardless of how well it was transmitted. Banda Aceh, on the northern tip of Sumatra, was devastated in 2004 because people did not have time to react, while there is evidence that some small nearby island communities fared better where traditional knowledge of the natural warning signs such as the sudden receding of the tidal waters was employed, and residents were able to flee to higher ground. Meanwhile, the tourist destinations of Phuket and Phi Phi, and nearby locations in Thailand had 2 hours, but the warnings were lacking. Visitors lacked necessary knowledge of nature’s warning signs and how to react, and may not have felt the earthquake, so many lives were lost.

In response to the enormous loss of life in the 2004 Indian Ocean tsunami, the Global Tsunami Warning and Mitigation System was put in place. The Indian Ocean tsunami warning system now integrates the signals from seismographs and DART Buoys and transmits data to 26 national centers. Warnings at the local level are generated in the form of SMS messages, mosque loudspeakers, sirens, and other methods to warn citizens. How well the warnings translate into lives saved due to rapid response and appropriate behaviors by the citizens depends on each step working properly. The failure of one of the steps can lead to disaster. If the citizens do not have the knowledge needed to take effective action, then the process will not work, and lives will be lost.

In 2012 another earthquake occurred near Banda Aceh in the Indian Ocean, so the newly implemented warning systems were put to the test. In this case, no tsunami was generated by the earthquake, but unfortunately, the weaknesses in the system were revealed. Despite the efforts expended to increase levels of tsunami preparedness since 2004, including new tsunami evacuation shelters and education programs, chaos ensued. Hearing the tsunami warning, people panicked and tried to flee by car, resulting in gridlock on the roads. It was clear that better guidance from the local government was needed, including clear evacuation route signage and regular drills. For more detail on this topic, read the National Geographic article Will Indonesia Be Ready for the Next Tsunami? Clearly, more work is still needed and ongoing to address these weaknesses.

Learning Check Point

We will spend a few minutes also revisiting the accounts of historic tsunami events – in particular, the 1960 event and its effects in Chile and Hilo, Hawaii, and the important messages about how to survive a tsunami. Please re-read some of the accounts of survival during tsunami events in Heed Natural Warnings .