Initially, the Earth Sciences Ministry and the National Disaster Management Authority issued a tsuanmi warning for Andaman and Nicobar Island and an alert to coastal areas of Andhra Pradesh and Tamil Nadu.
Later, in subsequent bulletions, the two organisations virtually ruled out tsunami in Andaman and Nicobar Islands and elsewhere in the country. "There is no specific threat. It was a watch and alert. There is no likelihood of any tsunami in the Indian Ocean region," NDMA Vice President Sashidhar Reddy told PTI.
He said the earthquake that struck the Sumatra islands was not the kind of tremors that usually triggers tsunami tidal waves. "It is the kind of strike and slip earth quake which does not trigger tsunami. There was no vertical displacement of water under the sea," he said.
"Tsunami possibility is virtually ruled out," he said, adding that the Andaman and Nicobar Islands administration and the Army stationed there had informed the NDMA that so far no waves have been noticed in the island.
The initial projections issued by the Indian Tsunami Early Warning Centre (ITEWC) showed the tidal waves triggered by the quake hitting parts of Nicobar, Komatra and Katchal minutes after it struck the region at 14:08 IST.
The ITEWC also issued an alert for coastal Tamil Nadu, Andhra Pradesh and the Andaman islands forecasting the arrival time of the first wave.
Strong tremors were felt in Chennai and some other nearby areas. People in multi-storeyed apartments and those working in high rise buildings rushed out to open areas. Kolkata and its neighbourhood were rocked by tremors which were also felt in North 24 Parganas adjoining Kolkata and in the north Bengal town of Siliguri.
A large number of people rushed out of offices in Park street and downtown BBD Bagh area here as windows and doors rattled. According to reports, some buildings on Park street developed cracks. Metro Rail services in the metropolis were suspended from 2:42 pm and passengers were asked to vacate stations.
The Pacific Tsunami Warning Center in Hawaii said a tsunami watch was in effect for Indonesia, India, Sri Lanka, Australia, Myanmar, Thailand, the Maldives and other Indian Ocean islands, Malaysia, Pakistan, Somalia, Oman, Iran, Bangladesh, Kenya, South Africa and Singapore.
A tsunami watch means there is the potential for a tsunami, not that one is imminent. The US Geological Survey said the powerful quake was centered 33 kilometers beneath the ocean floor
A giant 9.1-magnitude quake off the country on Dec. 26, 2004, triggered a tsunami in the Indian Ocean that killed 2,30,000 people, nearly three quarter of them in Aceh.