The earthquake was centred almost exactly halfway between Meulaboh on the southern coast of Sumatra and Lhoksemawe on the north coast.
The Thai government Seismology Department noted that the tremors could also be felt in high buoildings in Bangkok.
San Janatarwong, chief of the department of Disaster Prevention and Mitigation said that the quake caused no known damage in Phuket. He added that no aftershocks are expected.
AFP later quoted a doctor in Indonesia's Aceh province as saying that about 50 people were injured when their houses collapsed.
“We have received around 50 people with injuries suffered when the walls of their houses collapsed," said Ema Suryani, a doctor at a health clinic in Lampahan city, Bener Meriah district.
"The injuries vary from open wounds to broken bones."