The U.S. Geological Survey said Wednesday the quake was centered 20 miles (33 kilometers) beneath the ocean floor around 308 miles (495 kilometers) from the provincial capital of Banda Aceh.
Said, an official at Indonesia's Meteorology and Geophysics Agency who goes by only one name, said a tsunami warning has been issued.
Indonesia straddles a series of fault lines that makes the vast island nation prone to volcanic and seismic activity.
US seismologists issued an Indian Ocean tsunami watch but till late, it was reported that the tsunami only generated small waves.
The 8.6-magnitude earthquake was followed by an immense aftershock, measuring 8.2, off the Indonesian island, raising a new tsunami threat.
As per the report of a geophysicist with the US Pacific Tsunami Warning Center in Hawaii, this earthquake was “no way near†the ones that struck Asia and Japan in 2004 and 2011 respectively. The current earthquake only generated mediocre waves but the situation was still being monitored as such earthquakes usually generate an enormous and destructive tsunami.
The geophysicist said that the tsunami measured a mere 35 centimeters (14 inches) near Padang, Indonesia, but could enlarge to as high as a meter (3 feet 4 inches) near Sri Lanka.
The Pacific Tsunami Warning Center, in an official statement, following the quake stated that "sea level readings indicate a tsunami was generated. It may already have been destructive along some coasts."
The Pacific Tsunami Warning Center said the areas under tsunami watch following Wednesday's quake and aftershock included: Indonesia, India, Australia, Sri Lanka, Myanmar, Thailand, Maldives, Malaysia, Mauritius, Reunion, Seychelles, Oman, Pakistan, Somalia, Madagascar, Iran, United Arab Emirates, Yemen, Comores, Mozambique, Kenya, Tanzania, Crozet Islands, Bangladesh, Kerguelen Islands, South Africa and Singapore.
The first quake struck at 2:38 pm (0838 GMT) at a depth of 33 kilometers (14.2 miles) with its epicenter some 435 kilometers (270 miles) from Banda Aceh.
The US Geological Survey said the aftershock struck at 10:43 GMT, 615Â kilometers (382 miles) from Banda Aceh.
A giant 9.1-magnitude quake off the country on Dec. 26, 2004, triggered a tsunami in the Indian Ocean that killed 230,000 people, nearly three quarter of them in Aceh. AP
