2004 Indian Ocean Tsunami

The 2004 Indian Ocean Tsunami began at one minute before 8:00 am on sunny and beautiful morning on December 26. The megathrust earthquake lifted the seabed and moved it sideways along a 1,600 km (1000 mile) crack in the Earth’s surface. The Indian Plate slipped beneath the Burma Plate during the 8.3 to 10 minutes that it took for the rocks to fracture along this length of the seabed.

Sri Lanka damage NOAA

Tsunami damage in Sri Lanka 2000 miles away 
 from the earthquake's epicenter

Megathrust earthquake
Trillions of tons of rock was moved during the event as well as huge quantities of water was displaced as the seabed shifted. The 
2004 Indian Ocean Tsunami waves were created by the energy of the event that swept outward along entire length of the rupture. The maximum slippage was near Banda Aceh where the land slipped about 15 meters during this megathrust earthquake.

How the tsunami waves move
The waves traveling at about the speed of a jet airplane swept across the Indian Ocean to eleven low lying countries where they brought death and destruction. As the waves reached shallow water they slowed up and the water piled up creating waves that were 15 meters (50 feet) high as they swept ashore. The waves swept inland in places over 2 kilometers (1.2 miles) inland.

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Water receded exposing the seabed
2004 Indian Ocean Tsunami waves that came ashore in distant lands were sometimes preceded by the ocean water receding. The receding water exposed the seafloor allowing many people to wander around taking pictures of the exposed land before the wave hit. Many children fascinated with the receding water ran out to look at stranded fish and boats on the sand. Receding water prior to a tsunami coming ashore often gives people 5 minutes to run to for higher ground.

Two people who knew the warning signs
One British student vacationing in Thailand knew the warning signs from a geography lesson. She warned her family and other people in the area where they were able to get to higher land before the waves came ashore. Another India man had watched a National Geographic show on tsunamis saw the water receding. He warned his village of the danger and saved his entire village. 

How tsunamis are generated
2004 Indian Ocean Tsunami waves were generated by lifting or lowering of the seafloor over a large area of the ocean floor. Tsunamis are generally by powerful megathrust earthquakes where one tectonic plate slips beneath another plate.

Landslides that crash into bays can create some of the largest tsunami waves in a local area. A landslide in Lituya Bay, Alaska on July 9, 1958 occurred when an 8.3 earthquake triggered a landslide that crashed into Lituya Bay. The height of the wave was 516 meters (1,720 feet) high. It was the highest megatsunami ever recorded. The largest earthquake-generated tsunami in recorded history was 33 meters (108 ft.) tall.

Moment magnitude scale measurement
Scientists use the moment magnitude scale (Mw) to measure very large earthquakes. They use this scale because it takes in the size as well as the magnitude of the earthquake. Various experts have determined the 
2004 Indian Ocean Tsunami waves were generated by an earthquake that measured between 9.0 and 9.3 on the moment magnitude scale.

The USGS uses the number 9.1 Mw and recent research by a Cal Tech scientist believes it should be 9.2 Mw. It was the third largest earthquake ever recorded. It released more energy that all the bombs in WWII including the two atomic bombs dropped in Japan. 

More information about the oceans

The Oceans on our planet cover approximately 70% of the Earth. The water that covers our planet is essential to life on our planet. From space the Earth looks like a blue ball partly covered with white wispy clouds.

The Great Barrier Reef off the coast of Australia are one of the seven great wonders of the natural world. Find out more about this World Heritage Site.

The Mid Atlantic Ridge is a divergent plate boundary where continental plates are moving apart down the middle of the Atlantic Ocean.

Viperfish are one of the fiercest predators living in the deep ocean. Find out how they attract their prey with a “fishing lure” and impale their prey with fang-like teeth.

Oceanic Zones are specific areas of the ocean. Most ocean life lives in one specific zone. Marine biologists have discovered some animals, whales, can dive to great depths to hunt for food.

The 2004 Indian Ocean Tsunami lifted the seabed and moved it sideways along a 1,600 km (1000 mile) crack in the Earth’s surface. The Indian Plate slipped beneath the Burma Plate during the earthquake.

Rift Valleys are not caused by erosion but are created by tectonic activity. These valleys form when oceanic plates are moving in different directions forming a divergent boundary.

Marine Sponges are sessile animals that look like plants. Some sponges have been found living on the ocean floors that are over 8,800 meters (5.5 miles) deep.

Caribbean Spiny Lobsters are found in tropical and sub-tropical waters. They are also known as Florida spiny lobsters and are famous for their migration each year into deeper waters.

Rogue Waves for centuries were believed to be tall tales sailors told during shore leave. They said waves rose out of the sea as a vertical wall of water that crashed into a ship without warning.

Ghost Crabs live on beaches in tropical and sub-tropical regions. They are found along beaches from Rhode Island south to Brazil. They only need to wet their gills to live on land.

Black Smokers (hydrothermal vents) were discovered by scientists aboard the Alvin in 1977. An entire ecosystem lives around the chimneys with bacteria the base of the food chain.

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