The earthquake's epicenter was in Sembalun Subdistrict, in East Lombok Regency. It registered at magnitude 6.4 on the moment magnitude scale, at a shallow depth of just 14 kilometers -- close enough to the surface to cause intense localized damage. Local residents said it was the strongest quake they had ever felt on Lombok. The shaking reached Denpasar in Bali, some 120 kilometers to the west, where a temple in Karangasem Regency collapsed and a local court was damaged. Within hours, the BMKG recorded 276 aftershocks between magnitude 5.0 and 5.5, with the largest reaching 5.7. By August 3, more than 500 aftershocks had been logged. What no one yet understood was that this earthquake was merely the opening act -- a foreshock to the magnitude 6.9 event that would devastate the island exactly one week later.

Mount Rinjani rises 3,726 meters above Lombok, its caldera holding the turquoise waters of Lake Segara Anak. It is one of Indonesia's most popular trekking destinations, drawing hikers from around the world to its crater rim and hot springs. On the morning of July 29, the mountain became a trap. Landslides struck the northern slopes, severing the hiking routes. The National Search and Rescue Agency identified two groups of stranded hikers: one near Segara Anak Lake, the other at a basecamp lower on the mountain. Initial reports were contradictory and confused -- 500, 600, 700 hikers, depending on which official was speaking. The problem was that most hikers had not been registered by their tour guides, making an accurate count impossible in the immediate aftermath. Officials eventually determined that more than 1,200 people had been on the mountain, roughly 700 of them foreigners from 26 countries. The largest contingent -- about 300 -- were Thai nationals.

Search and rescue teams prepared two helicopters for the evacuation, but the operation was anything but swift. The rugged terrain, continuing aftershocks, and the sheer number of people on the mountain made extraction slow and dangerous. On July 30, more than 700 hikers remained above the treeline. The government immediately closed Mount Rinjani National Park and banned all hiking activities, citing the risk of further landslides. President Joko Widodo, who had been planning to visit West Nusa Tenggara before the earthquake, ordered Governor Muhammad Zainul Majdi to deploy every available search and rescue resource. The Bali Red Cross dispatched medical experts. Social Minister Idrus Marham confirmed that the government was sending aid to the affected areas. By August 1, three days after the earthquake, all 1,226 hikers had been rescued from the mountain. None had died on Rinjani itself, though 20 people were killed across Lombok, with the toll rising from 10 to 16 to 17 to 20 over the following days as reports filtered in from remote villages.

While the mountain rescue dominated international headlines, the damage below was severe. In Sembalun, a community health center was significantly damaged, leaving medical care in the worst-hit area compromised. Patients at dr. Soedjono regional hospital in Selong had to be evacuated outside. Blackouts swept across Lombok as the national electricity company temporarily cut power to East Lombok Regency for safety inspections. Telecommunications went down. The BNPB's spokesman, Sutopo Purwo Nugroho, estimated that more than 1,000 structures had been damaged or destroyed island-wide. Governor Majdi declared a three-day state of emergency. President Widodo visited survivors on July 30, touring collapsed homes by helicopter and announcing compensation of at least 50 million rupiah -- roughly $3,400 -- for each damaged or destroyed building, with the Indonesian Armed Forces assisting in reconstruction.

The July earthquake killed 20 people and displaced thousands. One week later, on August 5, the magnitude 6.9 mainshock would kill 563. The July 29 event had weakened buildings across Lombok, setting up thousands of structures for failure when the larger quake arrived. The BMKG would later confirm that the July earthquake was indeed a foreshock -- a seismological term that carries a terrible irony, since foreshocks can only be identified after a bigger event follows. On the morning of July 29, with landslides still smoldering on Rinjani's slopes and hikers still waiting for rescue on the mountain, the people of Lombok had every reason to believe the worst was behind them. The Flores Thrust had other plans. Across the strait, Malaysia's Prime Minister Mahathir Mohamad pledged aid, and the Malaysian Global Peace Mission deployed a survey team with initial funding. It was a gesture of solidarity for what everyone assumed was a single disaster. The earth would correct that assumption six days later.