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What the elephants knew


Date: 2015-10-07; view: 387.


The Tsunami

Deep under the Indian Ocean, at the epicentre of the quake, the 20m (65ft) upward thrust of the seafloor set in motion a series of geological events that were to devastate the lives of millions. Billions of tons of seawater, forced upward by the movement of the seabed now flowed away from the fault in a series of giant waves.

The only people in the world to have any idea what had happened were thousands of kilometres away on the island of Hawaii. But, relying on seismic data alone, the scientists at the Pacific Tsunami Warning Center had no idea the earthquake had unleashed an ocean-wide tsunami. It was a full 50 minutes after they first picked up the tremors that they issued a warning of a possible local tsunami.

Thirty minutes after the shaking had subsided, the first wave, travelling eastwards, crashed into Sumatra. On the shores directly facing the epicentre, the waves reached heights of 20m (65ft), stripping vegetation from mountainsides 800m (0.5 mile) inland, capsizing freighters and throwing boats into the trees.

The city of Banda Aceh, just a few kilometres further round the coast was almost completely destroyed, killing tens of thousands of people in just 15 minutes.

 

 

Leaving a devastated Sumatra behind, the series of waves continued across the Andaman Sea towards Thailand.

A herd of elephants in the mountains seemed to know it was coming. They began behaving strangely, stamping the ground and tugging at their chains, eventually breaking away to run to the hills. Elephants have special bones in their feet that enable them to sense seismic vibrations long before we can.

Animals taking to the hills was not the only sign that something was about to happen. Due to the complex way in which the seafloor ruptured, some waves set off travelling with the crest first, others traveling trough first. The trough, reaching the shores of Thailand, caused the sea to disappear off the beaches. It is one of the classic warning signs of an approaching tsunami.

Tragically, many tourists went down to the beach to look, some to rescue fish left flapping on the sand. A few minutes later, the first wave hit Thailand. A thousand tons of water crashed down on each metre of beach. At Khao Lak, the wave reached 10m (30ft) and caused billions of pounds of damage. The human cost was far greater - nearly 5,000 confirmed dead and 3,000 still missing.

At the same time, the westbound series of waves were heading for Sri Lanka. In the deeper waters of the Indian Ocean, barely noticeable at just a 30cm (1ft) above the surface, they were travelling at some 800 km/h (500 miles per hour).

 


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