The earthquake struck the Flores Sea but there has been no tsunami warning issued.
The quake was located 153 km northeast of Raba at a depth of 564.7 km, the US Geological Survey said.
There are about 3000 people living within 100 kilometres.
Deep earthquakes generally cause less damage.
Indonesia is prone to earthquakes because of its location on the “Ring of Fire,” an arc of volcanoes and fault lines in the Pacific Basin.