The earthquake, which hit 234 km (145 miles) south of Lombok, at a depth of 29 km (18 miles), also briefly startled tourists on the Indonesian resort island of Bali.
The quake was strong, with tremors lasting for three to four seconds, but did not trigger a tsunami alert, said Sutopo Purwo Nugroho, a spokesman of Indonesia's Disaster Mitigation Agency (BNPB).
"The quake went on for quite a while," said a witness in Lombok. "People ran out from houses in panic."