Thursday's seismic event follows a 6.9 magnitude quake Sunday that flattened homes and stranded thousands on Lombok's northern coast and the nearby Gili Islands.
Accidents, disasters and safety
Resorts and spas
Travel and tourism
Continents and regions
Environment and natural resources
Islands and reefs
Landforms and ecosystems
North Lombok, more residential and less developed than the island's resort-filled south, was devastated by Sunday's quake. Some villages in the region were completely destroyed, witnesses told CNN.
Aid has been slow to trickle in, due to damage to roads leading to the affected areas and the relatively remote location of the island. Rescue workers have been searching debris for days in the hopes of finding people alive amid the rubble.
Hundreds who survived Sunday's quake are huddled in evacuation centers, where they sleep on plastic mats. Food is scarce, and some of the children are eating crackers dipped in chili sauce.
Many remain traumatized from the Sunday quake, aid workers told CNN, afraid to return indoors in case of powerful aftershocks.
"More damage, more trauma, more loss -- people are scared," said Endri Susanto, who runs a nongovernmental organization assisting with relief efforts in Lombok. "People are very scared to go to their houses and very scared to stay in their houses."
Susanto told CNN by phone that people started screaming when Thursday's quake hit. Soon after, ambulances began whizzing by, sounding their sirens. He said friends in central Lombok had told him that houses there had started to crack.
The earthquake felt strong in Mataram, a city on Lombok's west coast, Susanto said. It could also be felt on Bali, another popular resort island in Indonesia to Lombok's west.
A third quake
Indonesia is no stranger to earthquakes. The archipelago is part of the Pacific Ring of Fire, a 40,000-kilometer (25,000-mile) area of intense seismic and volcanic activity where most of the world's earthquakes occur.
Lombok has been hit with three major quakes in less than two weeks. A shallow 6.4 magnitude earthquake struck July 29, killing more than a dozen people and stranding hundreds on top of Mount Rinjani, a popular hiking area.
But it was the second one that was the most devastating. It was so destructive that Susanto told CNN he thought Thursday's quake would not cause much damage in the north after most buildings had already collapsed.
It's unclear how many people were killed in the earthquake Sunday. Indonesia's state-run Antara news agency reported 347 had died in the quake's aftermath, citing numbers from the North Lombok Regency of the Regional Disaster Management Agency. But Sutopo Purwo Nugroho, spokesman for the country's National Disaster Management Agency, said in a statement that 259 were killed. He cautioned the number is expected to rise.
About 1,000 were hospitalized and more than 165,000 people have been displaced due to Sunday's quake, Sutopo said.
The temblor also stranded tourists on Lombok and the popular Giili Islands to its west, famous for its white sand beaches and clear waters. Photos from Indonesian rescue authorities showed thousands of people crowded on a beach awaiting rescue.