Tons of rock and mud were dislodged on Mount Rinjani in the 6.4-magnitude quake, which struck early Sunday (July 29) and was followed by scores of aftershocks, blocking the hiking routes that criss-cross the mountain.
Around 560 people were estimated to be trapped on Rinjani overnight, including citizens from the United States, France, the Netherlands, Thailand and Germany, as well as many other countries, search and rescue officials said.
Search and rescue officials said tourists had now started to descend the active volcano but were unlikely to arrive at its base before nightfall.
“At the moment both domestic and international tourists are on their way down,” I Gusti Lanang Wiswananda, a spokesman for West Nusa Tenggara search and rescue, said.
Hikers were able to start descending the mountain after guides discovered an alternate route that was unaffected by the landslides, Wiswananda said, adding the evacuation will most likely stretch into today (July 31).
Hundreds of other hikers managed to get off the mountain on Sunday, according to officials.
At least 16 people were killed in the earthquake across affected areas of Lombok, while hundreds of buildings were destroyed including a health clinic.
The quake created panic on the holiday island and sent locals and tourists running outside their homes and hotels.
Helicopters and search teams were deployed to scour the volcano’s slopes and drop food supplies for those stranded on the mountain.
The search will be halted at sunset, search and rescue officials said.
“For supplies, they can still survive for another one to two days,” Agus Hendra Sanjaya, spokesman for Mataram’s search and rescue agency, said.
Rising some 3,726 metres above sea level, Rinjani is the second-tallest volcano in Indonesia and a favourite among sightseers keen to take in its expansive views.
Hiking trails on the mountain were closed following the quake due to fear of further landslides.
Thailand’s embassy in Jakarta said 239 of its citizens were stuck in the area surrounding the mountain.
Thai national Thanapon Worawutchainan, who was at the summit when the earthquake occurred, posted a video on Facebook showing people stumbling down the slopes in the aftermath.
He said the ground shook violently and people lay down until the tremors stopped.
“It looked like the mountain in front of me was going to collapse,” another stranded Thai, Funknathee Prapasawat, said on Facebook. “Some people were injured by rocks falling off the mountain.”
The epicentre of the earthquake was 50 kilometres northeast of Lombok’s main city Mataram, the United States Geological Survey said, far from the main tourist spots on the south and west of the island.
The initial tremor was followed by two strong secondary quakes and more than 100 aftershocks.
The jolt was felt some 100km away on the bustling resort island of Bali, although there were no reports of damage there.
In the hard hit village of Medas, north of Mataram, the majority of houses were destroyed and the area was deserted yesterday save for a few people searching for possessions in the rubble, a reporter at the scene said.
Some 160 people were injured in Lombok as a result of the quake, said Mohammad Rum, head of West Nusa Tenggara disaster agency.
A Malaysian was among the dead, with another six citizens injured, the foreign ministry in Kuala Lumpur said.
A total of 5,141 people are staying in temporary shelters and in need of clean water, Indonesian disaster mitigation agency spokesman Sutopo Purwo Nugroho told MetroTV.
Rinjawani Pebolaisia, an evacuee at a shelter in East Lombok, said they were lacking basic supplies.
“We hope that aid will arrive quickly – there are only instant noodles here,” Pebolaisia, 30, said.
“We also need milk for the children, diapers, there are also no blankets... Many people are sleeping outside.”
President Joko Widodo visited affected areas esterday and promised financial support for those who have lost their homes.
“We must be aware that our country is in the Ring of Fire, so people need to be prepared to face any disaster,” Widodo said.
Indonesia, one of the most disaster-prone nations on earth, straddles the so-called Pacific ‘Ring of Fire’, where tectonic plates collide and a large portion of the world's volcanic eruptions and earthquakes occur.
In 2004 a tsunami triggered by a magnitude 9.3 undersea earthquake off the coast of Sumatra in western Indonesia killed 220,000 people in countries around the Indian Ocean, including 168,000 in Indonesia.