At least 75 people are known to have died, and thousands more are missing after a powerful earthquake in Indonesia. It was rated at 7,6, and struck off the coast of Sumatra. Communications with the area were cut and few pictures have emerged. But phone reports from the scene say many people are buried in the rubble of a ruined hospital in the port of Padang, others say the airport buildings, schools and hotels have collapsed.Indonesia lies on a belt of intense seismic activity, known as the Pacific Ring of Fire. Sumatra Island is also home to huge oil and gas reserves. The first pictures showed damage from the countryside. Fewer people live here so the number of dead is not expected to be so high. Padang itself has nearly a million residents. The tremor was felt across the region. 400 kms away in Singapore, high-rise buildings swayed and office workers were evacuated. Offices in the Malaysian capital Kuala Lumpur also shook. A tsunami alert was issued after the quake, but was later lifted.