Strong Indonesian Earthquake Triggers Tsunami Warning Hotli Simanjuntak/European Pressphoto Agency Residents in Aceh fled to higher ground on Wednesday. BANGKOK - A powerful 8.6-magnitude earthquake struck more than 200 miles off the coast of the Indonesian island of Sumatra on Wednesday, spreading panic among residents and reviving memories of the devastating 2004 earthquake and tsunami in the same area. The Indonesian government said there were no reports of casualties or significant damage from the initial earthquake, but several strong aftershocks were reported in the afternoon and early evening. The largest measured 8.2, the United States Geological Survey said. The earthquake was felt in Bangladesh, India, Malaysia, Singapore and Thailand, news agencies reported, with coastal areas of southern Thailand and eastern India declaring tsunami alerts and Indonesia issuing a tsunami warning following the aftershocks. Indonesia's president, Susilo Bambang Yudhoyono, told reporters at a news conference in Jakarta that the earthquake had caused "a little bit of panic." In Banda Aceh, which was devastated by the earthquake and tsunami in 2004, buildings shook for several minutes, and people poured into the streets from their homes, said Rizal, a resident of the city reached by telephone. "The only problem we had was people panicking," said Rizal, who like many Indonesians goes by only one name. The 2004 tsunami, caused by a giant 9.1-magnitude earthquake, killed 230,000 people in more than a dozen countries. Wednesday's earthquake was not as powerful, and seismologists said its horizontal motion made it less likely to trigger a large tsunami. A scientist at the Indian National Tsunami Early Warning System said there was "no major tsunami threat" to the east coast of the country. Tamil Nadu and south Andhra Pradesh, states that sit on the Bay of Bengal, remain under alert for now. "We're monitoring sea level gauges," said the scientist, who declined to give her name. On the Andaman and Nicobar islands, the closest Indian territory to the earthquake's epicenter, officials and hotel managers said they felt the earth move at around 2:15 p.m., but said there was no sign of a tsunami or even big waves nearly two hours later. Commander Bindu Prakash, an officer with the Indian Navy based on the islands, said there had been no noticeable rise in sea levels even past the estimated time that the tsunami was supposed to hit the islands. He said the official tsunami warning was still in effect as a precaution. Deepika Mandal, an employee at the Fortune Resort Bay Island hotel in the capital of Port Blair said the sea was "absolutely calm." Vinnie Kalia, the owner of the Island Vinnie's Tropical Beach Cabana, had his 23 guests evacuate the resort around 3:45 p.m. to a hill next to the resort. "We evacuated about half an hour ago, but the ocean is calm as anything, so we canceled the evacuation," he said by telephone. "The coastal area has been vacated," said Prabhakar Rao, the top official at the District Disaster Control Room at Andaman & Nicobar. In Aceh, which sits on the northern tip of Sumatra, the earthquake knocked out electricity and tied up cellular phone service, according to Edo Iskandar, a 56-year-old driver who said he was drinking coffee at an outdoor restaurant when the earthquake struck in the midafternoon. "People start running out into the street," he said. All the people at the food stall, people from shops, houses, everybody was in the street panicking, running and looking for higher ground. The tsunami siren sounded, he said. The initial quake struck at a depth of 14 miles with an epicenter 269 miles southwest of Banda Aceh, according to the United States Geological Survey. The strongest aftershock was measured at a depth of 10 miles. Bruce Pressgrave, a geophysicist with the survey, said the first earthquake was believed to have come from a "strike-slip fault," which would reduce the likelihood of a destructive tsunami. The wall of such faults moves horizontally with little vertical motion, he told a BBC news program. "Since the motion is horizontal, it is not moving the water column, it is less likely to produce a destructive tsunami," Mr. Pressgrave said. Muktita Suhartono contributed reporting from Bangkok; Nikhila Gill, Sruthi Gottipati, Nida Najar from New Delhi; Kevin Drew from Hong Kong and J. David Goodman from New York.