Quake-hit Sumatra lifts tsunami alert
The tsunami warning in Western Indonesia, triggered by the 7.8 magnitude undersea earthquake that struck Sumatra, was lifted after Indonesia's quake monitoring agency BMKG stated that the main tsunami waves had passed the island. Tsunami warnings for the West Australian coastline, Coco Island and Christmas Island were called off as well. However, people have been advised to stay away from beaches and harbours.
Indonesia straddles the world's most seismically active region, the Pacific Ring of Fire. Different plates on the earth's crust meet in this zone, creating a large number of earthquakes and volcanoes. Earthquakes of magnitude 5 ( Richter scale) happen almost daily in Indonesia. Every year, 2-3 earthquakes of magnitude greater than 7 hit the country, causing casualties and damage to infrastructure and the environment.
The Pacific Ring of Fire runs up along the western coast of South and North America, crosses over Aleutian Islands in Alaska, runs down the eastern coast of Asia past New Zealand and into Antarctica's northern coast. About 80% of the world's largest earthquakes occur in this zone.
A 9.15-magnitude quake opened a fault line deep beneath the ocean on 26 Dec 2004, triggering a tsunami as high as 17.4 metres that crashed ashore in Aceh, on the northwest tip of Sumatra. The tsunami caused a major humanitarian crisis in Indonesia with the death toll crossing 167,000 along with massive damage to infrastructure. Another tsunami hit Java in 2006, causing 600 deaths.
Large earthquakes having epicenters or fault lines near or on the ocean floor can generate tsunamis. Generally, earthquakes having magnitudes above 7.0 trigger tsunamis.
A powerful and shallow 7.8 magnitude earthquake struck off the Western Indonesian coast at 19:49 local time, sparking fears of triggering a calamity similar to the devastating 2004 Indian Ocean earthquake and tsunami. A tsunami warning was issued and people were evacuated to higher ground. No deaths or major damages to buildings were reported and daily life resumed as normal the next day.
The US Geological centre said the epicentre of the earthquake was 808 km south-west of Padang city in Indonesia.
