Case Study On Tsunami In Thailand
A timeline of destruction
20 minutes before the water arrives Banda Aceh feels the force of the earthquake and buildings collapse. Across in the Pacific, at the Hawaii Pacific Tsunami Warning Centre pick up the seismic signals just one minute after the quake. Any earthquake above magnitude six results in a pager being sent to the scientists of the centre. The scientists used data from numerous sensors (including water level gauges), but they are only in the Pacific Ocean and have been used to help people for the past 50 years. A system such as this did not exist in the Indian Ocean. The scientists warned of a tsunami and issued a tsunami bulletin.
10 minutes after the earthquake in Sumatra (Aceh province) the wave is approaching at 600miles an hour, in the open ocean boats were hardly affected. As the wave neared land the wave grew by a process of amplification. The front of the wave slows down as it approaches the shore, but the back of the wave is still going its original speed, so the wave builds in size. Before it hits land, the approaching wave sucks water in from its leading edge exposing the sea bed at the coast for up to a mile; this led many people to their deaths in the disaster.
Tsunamis rush in as a surge rather than as a classic curved wave, and they have incredible wave lengths of hundreds of kilometres meaning that they keep coming in for 5 minutes or more. The mass caused huge damage –one cubic meter of water has a mass of one ton, every 1.5m of coastline was exposed to 1000tons of water. The water was also not clean; it had rocks, cars, and other debris which caused damage.
15minutes after the quake Northern Sumatra becomes the first place to be hit. It caused utter devastation. Banda Aceh was completely destroyed, with barely any buildings left standing. The height of the wave here was colossal, higher than the coconut trees. Ships were thrown up onto the land, and the cement works were destroyed. ¾ of the tsunamis victims died in Sumatra.
30 minutes after the quake, 7000 people are killed in the Nicobar Islands
45 minutes after the earthquake the scientists in Hawaii are still unaware of the tsunami. They issue an upgraded tsunami warning.
1 hour after the earthquake in Thailand, people still do not know that people have died in Indonesia. People climbed upon the tops of hotels to survive. The Geomorphology (shape and orientation) of the coastline determined death tolls along the coast of Thailand, and this was shown along the West coast of the Island of Phuket. The exposed bays which faced the wave bore the brunt of the wave, whereas bays which faced away got of relatively lightly. Surin Bay and Beach had a steep beach and protecting headland, and was relatively untouched. The water was only 30cm deep there, but in Kamala beach the bay faced the wave, had a very shallow gradient allowing the wave to build up and had low land behind the bay. Kamala was devastated. Buildings and decking were ripped up. Phuket was hit by a second wave 15 minutes later, which was even bigger than the first wave. Multiple waves in Tsunamis are normal. The second wave rolled around the whole of Kamala bay. As the water retreats back out to sea it pulled cars, debris, fishing boats and people back out with it.
2 hours after the earthquake, the wave reaches Sri Lanka. A train was running along the coast from Colombo to Galle. The train was hit by the wave of water, and split the train up. The second wave arrived soon after, killing most of the people who had survived the first wave on the train. 1500 people died on the train, 45,000 people died in India and Sri Lanka.
3 ½ hours after the earthquake the Hawaii Tsunami centre are shocked by the devastation, and upgraded their estimate of the size of the quake to 8.9. There were no contacts that the team could call, so they tried everyone they could who were ahead of the wave.
3 ¾ hours after the quake, the Maldives are only slightly effected.
7 hours after the quake, East Africa is next affected. News is finally getting to communities and in Kenya there was only one fatality as people were warned. The wave dissipates throughout the whole ocean across the globe.
Tsunamis are not new to Asia, Krakatau’s explosion in 1883 generated massive tsunamis. NASA showed that the tsunami called the Earth to wobble by 2 ½ cm and slightly shortened the day. The area affected has concerned scientists for years, and a network of deep ocean sensors could have saved thousands of people. There were no water level sensors, no warning systems and no disaster plans. This all contributed to the high death toll.