SINABANG, Indonesia (Reuters) - A major earthquake of 7.7 magnitude struck off the coast of Aceh in north-western Indonesia on Wednesday, triggering panic and power blackouts, but no deaths were reported and a tsunami alert was later lifted.
Neighboring Thailand and Malaysia also canceled tsunami warnings.
A Reuters photographer in Sinabang on Simeulue island, south of Aceh and close to the epicenter, said electricity was cut in the area and some people were injured, including a child with a head wound who had been hit by fallen masonry.
A local official said 17 people were hurt on the island, including four with serious injuries.
President Susilo Bambang Yudhoyono expressed relief the island of Sumatra appeared to have escaped major devastation.
"Thanks be to God the quake did not cause a tsunami or any significant damage," Yudhoyono told a briefing at Halim airport in the Indonesian capital Jakarta, about 1,200 km (750 miles) southeast of the quake's epicenter.
A Reuters correspondent who flew over Simeulue in a Hercules military transport plane saw a few houses with minor damage, and said fishermen had returned to the sea.
The resource-rich island of Sumatra, where Aceh is located, is an important supplier of commodities such as rubber, palm oil and liquefied natural gas (LNG), but there were no immediate reports of delays in shipments because of the quake.
In December 2004, a magnitude 9.15 quake off Aceh triggered an Indian Ocean tsunami that killed about 226,000 people in Indonesia, Sri Lanka, India, Thailand and nine other countries.
Wednesday's quake, which struck around 5:15 a.m. (2215 GMT), was centered 200 km (125 miles) west-northwest of the coastal town of Sibolga and was at a depth of 31 km, the U.S. Geological Survey said. The epicenter was around 215 km from Medan, the largest city on Sumatra, where blackouts also occurred.
There were a series of smaller aftershocks after the initial major quake.
The Hawaii-based Pacific Tsunami Warning Center initially warned the quake could generate a local tsunami, but later canceled its tsunami watch.
Indonesian officials said that a tsunami of 40 cm (15.75 inches) had been detected in a few areas including Banyak island, where some homes were flooded.
The quake struck while Muslims were attending dawn prayers and some mosques were reported damaged in Aceh.
Sumatra lies along the Pacific "Ring of Fire", one of the world's most active seismic faultlines, and is frequently hit by earthquakes.
A 7.6 magnitude quake struck last September off the city of Padang, southeast of Wednesday's epicenter, killing more than 1,000 people.
Additional reporting by Ed Davies and Olivia Rondonuwu in Jakarta, Telly Nathlia in Medan and Reza Munawir in Banda Aceh; Editing by Jerry Norton