NEW DELHI, Dec. 27 (UPI) -- A strong aftershock, registering 6.3, struck the Indian Ocean Monday near the site of Sunday's giant earthquake off the Indonesian island of Sumatra.
Scientists at the U.S. National Earthquake Data Center near Denver said so far 10 significant aftershocks -- all registering at least 5.9 on the Richter scale -- have occurred since the initial temblor.
The death toll mounted past 23,500 in Indonesia, India, Sri Lanka and Thailand after massive tidal waves devastated their coastlines, Sky News reported.
The quake, the epicenter of which was located about 1,000 miles northwest of the Indonesian capital of Jakarta, occurred off Sumatra's northwestern tip in an active geological region and ruptured an estimated 600-mile-long stretch of the Earth beneath the Indian Ocean.
The movement of Earth's crust during the quake apparently was so severe, and the energy released so strong, that it created giant tsunamis -- tidal waves that travel hundreds of miles an hour -- sweeping across the Indian Ocean and devastating communities in eight countries.
Hundreds of thousands were injured and many thousands remained missing, CNN reported.
Rescuers began reaching areas that were cut off, and reported scenes of total devastation, with bodies stuck on trees as the waters receded, Sky News said.
At sunrise, 20,000 Sri Lankan soldiers and naval personnel launched relief and rescue efforts, and India deployed six warships carrying supplies, along with helicopters.
More than 10,000 people have been reported dead in Sri Lanka, more than 4,000 in Indonesia, while the Press Trust of India said at least 6,000 Indians were killed, and more bodies were being recovered.
