A powerful, 8.6-magnitude earthquake and an 8.2-magnitude aftershock off the west coast of Northern Sumatra today led authorities to warn that potentially devastating tsunamis might roar across the Indian Ocean.
But to the relief of millions who were immediately reminded of the devastating tsunami that rolled across that ocean in 2004, the waves generated by today's temblors were minor and the tsunami "watch" was canceled just before 9 a.m. ET.
The other welcome news: Initial reports indicated that damage from the quakes themselves may not have been extensive.
We began this post at 7 a.m. ET and added some updates soon after. Scroll down to see how the story developed.
Our original post and earlier updates:
The first reports from Indonesia and places nearby about the aftereffects of today's large, 8.6-magnitude earthquake are encouraging:
-- Reuters reports that the first tsunami generated by the temblor is headed for Indonesia's Aceh province, but at this point measures just under 7 inches in height. "It doesn't look like a major tsunami," Victor Sardina, a geophysicist at the Pacific Tsunami Warning Center, tells Reuters. "But we are still monitoring as tsunamis come in waves."
-- Indonesian President Susilo Bambang Yudhoyono told reporters earlier that "thanks God, from what I heard there is neither casualties reported nor major damage in Banda Aceh or other places."
The need for watchfulness has been underscored by word of an 8.2-magnitude "aftershock" in the same area.
According to the U.S. Geological Survey, the first earthquake happened at 4:38 a.m. ET this morning, or 2:38 p.m. Thursday local time, and was centered about 14 miles deep off the west coast of Northern Sumatra — 270 miles southwest of Banda Aceh.
It led the Pacific Tsunami Warning Center to issue an "Indian Ocean-wide tsunami watch" covering a vast area that includes coastlines of Indonesia, Australia, India, Thailand, Singapore, South Africa and regions in between.
The quake and tsunami warning immediately brought to mind, of course, the devastating 9.1-magnitude temblor and tsunami that struck the area on Dec. 26, 2004. The massive wave generated by that earthquake killed an estimated 230,000 people.
According to the BBC, today's earthquake was " felt as far away as Singapore, Thailand, Sri Lanka and India. 'There was a tremor felt by all of us working in the building,' a man called Vincent in Calcutta, India, told the BBC. 'All just ran out of the building and people were asked not to use the elevator. There was a minute of chaos where all started ringing up to their family and asking about their well-being.' "
NPR's Anthony Kuhn, reporting from Jakarta, tells our Newscast Desk that "residents poured out of their houses and headed for high ground" in the areas nearest the quake.
We will keep an eye on the news and update this post.
Update at 8:58 a.m. ET. Tsunami Watch Canceled:
The Pacific Tsunami Warning Center just said it has canceled the tsunami watch for countries along the Indian Ocean.
Update at 8:34 a.m. ET. Tsunami Watch Area "Now Reduced":
The Pacific Tsunami Warning Center says the "watch area" has been reduced to include Indonesia, India, Sri Lanka and the Maldives.
Update at 7:20 a.m. ET. Aftershock Prompts Another Tsunami Alert:
Reuters says the powerful aftershock has led Indonesia's Geophysics Agency to again warn of the "potential" for a tsunami.