Sigh of relief after Tsunami warning put coastal region on alert ends

Massive earthquake off the western coast in northern Sumatra triggered widespread panic in countries on the rim of the Indian Ocean yesterday. Indonesia, Malaysia, Thailand, India, Sri Lanka and even countries as far away as Kenya issued tsunami warning.

Sri Lankan Meteorological Department initially issued a Tsunami warning at 1415 hours on Wednesday the April 11, 2012 renewed it once again at 1630 hrs following an aftershock earthquake of 8.6 magnitude. As result people living in the coastal areas were evacuated to safer places But Sri Lanka withdrew Tsunami warning at 1815 hrs in the evening requesting the people to return to their homes.

In several parts of the country including the capital Colombo, tremors were reported after 2.00 pm by residents as well as office workers in Colombo

Regional authorities gave the all-clear in most countries last night, including in Indonesia where memories of the 2004 earthquake and tsunami that killed 170,000 in Aceh remain vivid. In Sri Lanka over 38,000 people were killed due to the Tidal wave in 2004.

Report from Indonesia says that the undersea quake of magnitude-8.6 took place shortly after 3:30pm (4.30pm Singapore time) some 434km south-west of Banda Aceh. It sparked hasty evacuations in the city that only recently recovered from the devastating tsunami that followed the 9.1-magnitude quake on Dec 26, 2004.

Scientist described the yesterday's earthquake as a strike-slip quake, it causes a horizontal tearing movement. While that causes vibrations in the sea, it does not displace the seabed, unlike the one in 2004 known as a mega-thrust quake that heaves vertically, displacing large volumes of water.

Foreign media reported a second quake measuring 8.2 struck 618km south-west of Banda Aceh more than two hours later. The resulting tsunami detected in Meulaboh was only 0.8m high, a far cry from the waves of up to 30m that struck in 2004.

Sumatra's west coast has been particularly volatile in recent years. A magnitude-8.6 quake off the island of Nias in March 2005 killed some 1,300 people.

A magnitude-7.6 quake near Padang in September 2009 killed more than 1,100, many of them trapped in the rubble of collapsed buildings.

Police Spokesman SP Ajith Rohana said that the tsunami early warning system went well, and the community readily responded by evacuating to safer places while Police deployed static guards, foot patrol in the areas from where the people were evacuated