A magnitude 7.7 quake devastated parts of Flores before another strong earthquake struck North Sumatra hours later.
SIKKA, INDONESIA — At least 51 people were killed and thousands were forced from their homes after a powerful magnitude 7.7 earthquake struck eastern Indonesia, triggering landslides, damaging buildings and cutting roads before another strong earthquake hit the country hours later.
The deadliest damage was reported in East Nusa Tenggara province after the first quake struck early Saturday, Aug. 15. Officials said Sunday that 36 people were seriously injured and 77 suffered minor injuries. About 5,000 people had been evacuated as authorities continued rescue operations across affected communities on Flores Island. The later earthquake, a magnitude 6.9 event in North Sumatra, was much deeper and was not reported to have caused major damage or casualties.
The first earthquake struck offshore near Flores and was followed by hundreds of aftershocks. Indonesian authorities recorded about 341 aftershocks by Sunday. The shaking triggered landslides that blocked roads and initially prevented rescuers from reaching some communities. Communications and electricity were also disrupted, making it difficult for officials to determine the full extent of the damage.
More than 3,300 people in the Sikka region either evacuated on their own or took shelter in a sports arena, according to Indonesia’s National Disaster Mitigation Agency, known as BNPB. Some residents spent the night outdoors because they feared damaged buildings and further tremors. Temporary medical treatment was also provided outside a hospital in the port town of Maumere because of earthquake damage and continuing safety concerns.
Authorities said rescuers eventually reached areas around Maumere that had been isolated by landslides. More than 1,300 homes were reported damaged across the affected region. Officials had not provided a firm count of missing people by Sunday, although authorities said people were believed to remain trapped beneath rubble in some locations.
More than 3,500 military and police personnel were deployed to support search, rescue and relief operations. Power outages also disrupted fuel supplies, with state energy company Pertamina reporting that 20 petrol stations were not operating. The provincial government was considering declaring an emergency, a move that would allow additional funding and resources to be directed to the disaster response.
The initial quake also prompted authorities to issue a tsunami warning and order people in coastal communities to move to higher ground. The warning was later lifted. Monitoring recorded smaller tsunami waves in several areas, including coastal communities on and around Flores. The earthquake also damaged schools, health facilities, places of worship, government offices and other public infrastructure.
Hours after the eastern Indonesia disaster, a magnitude 6.9 earthquake struck North Sumatra in western Indonesia. The U.S. Geological Survey placed that earthquake about 172.5 kilometers, or 107 miles, below the surface. Indonesian authorities said its depth reduced the likelihood of severe surface damage, and no deaths from the second quake were immediately reported. The two events occurred in separate parts of the vast Indonesian archipelago.
Indonesia regularly experiences earthquakes because it sits along the seismically active Pacific Ring of Fire, where several tectonic plates meet. Flores has suffered major earthquakes before, including a magnitude 7.5 event in 1992 that caused widespread destruction. The latest magnitude 7.7 quake was Indonesia’s deadliest since an earthquake in West Java killed hundreds of people in 2022.
Search and relief operations continued Sunday as crews worked to reopen blocked roads, reach isolated communities and determine whether more people were missing. Authorities warned that aftershocks remained a concern while officials assessed damage and considered an emergency declaration for East Nusa Tenggara.
Author note: Last updated August 16, 2026.