"We're getting reports that on the islands it may worse than December in terms of loss of life and infrastructure," Barrand said in a telephone interview from the Sumatran town of Padang. She said SurfAid, which was organized by surfers in 2000, was preparing a barge to take relief supplies to Nias and other nearby islands.
In Banda Aceh, the capital of Aceh province on Sumatra, people reported tremors that lasted several minutes and said power was lost for about 10 minutes. At least 106,000 people were killed in Aceh in the December tsunami.
Sri Lankans gather in Colombo, the capital, after fleeing their homes along the coast following a tsunami alert. Advisories or evacuation orders were issued in several countries in the Indian Ocean region, including India and Thailand. Many areas are still recovering from December's devastating tsunami.
(Anuruddha Lokuhapuarachchi -- Reuters)
Post's Nakashima reports from Jakarta, Indonesia, on reaction to the powerful earthquake.
Residents said they had been instructed in recent community briefings to seek higher ground if they felt a large earthquake. "If things happen, we have to leave," said Iwan, a security guard at a house in downtown Aceh who was reached by cell phone.
Refugees who still live in tents and temporary housing streamed along darkened Banda Aceh streets clogged with cars and motorbikes and fled to higher ground. Some cried and clutched children in their arms. Others sought shelter in mosques, which proved resistant in December when the ocean surged ashore.
"Where can I go? You can't outrun a tsunami," called out one man rushing into a mosque, the Associated Press reported.
The Monday quake "was the biggest I've ever felt," said Helene Barnes, regional manager for Asia and Pacific for Fauna & Flora International, an environmental group. But she said that no houses appeared to have collapsed in her area and that her colleagues in Calang on the western coast of Sumatra had reported no damage.
"Here in Banda Aceh, there have been a lot of people panicking. A lot of people running and walking and driving from the sea. It's not an organized evacuation, but lots of people were moving. I can hear lots more vehicles than normal," she said.
At 1:45 a.m., Indonesian Metro TV broadcast footage of a man with a megaphone shouting in Indonesian on the streets of Banda Aceh. "The situation has returned to normal," he announced. "The water is not rising. So you can all go back to your homes."
Governments in other countries issued warnings based on the possibility of a tsunami because of the quake's intensity.
Indian officials activated a disaster program early Tuesday and issued an advisory for eight coastal states, citing the "possibility of this earthquake triggering a tsunami." Dhirendra Singh, a Home Ministry official, said precautions were needed for six to eight hours after the quake. The advisories were dropped Tuesday morning when no tsunami developed.
While officials in Indian Ocean nations have discussed a satellite-based tsunami warning network, it has not yet been implemented. "Our biggest preparation is that there are no people on the coast," said Shivraj Patil, India's home minister. "We are asking people not to panic, but at the same time to be vigilant. Every earthquake does not convert into a tsunami."
Public address systems in the southern state of Tamil Nadu issued alerts and warned some coastal residents to move inland as a precaution. At Port Blair, in India's Andaman and Nicobar archipelago off the coasts of Thailand and Burma, officials said sea levels had not changed. Portions of the islands were devastated in the December tsunami.
Sri Lankan officials also held emergency meetings and broadcast warnings. Indian television reported incidents of panic along the Sri Lankan coast, with people fleeing their houses. Two people were reportedly killed in Sri Lanka during a panicky evacuation from the coast in a Tamil rebel-held area, the Associated Press reported.
In Thailand, officials issued advisories for southern regions where an estimated 5,300 people died in the December tsunami. "Please evacuate to higher places now," said Samith Dhammasaroj, a senior Thai official, in a radio broadcast.
Six Thai provinces were given evacuation orders, including Phuket island, a tourist location that had been luring visitors back with bargains.
Special correspondent Rama Lakshmi in New Delhi and Yayu Yuniar in Medan contributed to this report.