A magnitude 7.7 earthquake struck off the coast of eastern Indonesia early on Saturday 15 August, killing at least 38 people, collapsing buildings and sending residents of Flores island running for higher ground.

The US Geological Survey placed the epicentre about 60 to 68 kilometres north-northwest of the city of Ende, in East Nusa Tenggara province, at a depth of roughly 10 kilometres. The quake hit at 5:58am local time. Strong aftershocks followed, including tremors of magnitude 6.1 and 5.9 north of Ende.

The toll has risen steadily through the morning as rescuers reached more areas, and officials expect it to climb further.

What is known so far

The heaviest confirmed damage is around Maumere, the main town of Sikka regency on Flores. Rescuers there found twenty dead, six injured and two people trapped under rubble, the head of the city’s rescue agency, Fathur Rahman, told Reuters early on. Yohanna Embu, a Sikka resident, described widespread damage and said the waiting room at the port terminal in Maumere had collapsed.

Damage has also been reported in Ruteng and East Manggarai, in Bima in neighbouring West Nusa Tenggara province, and in parts of southern Sulawesi. Local television showed hospital patients being evacuated from buildings as a precaution, with staff moving beds, IV stands and oxygen cylinders outdoors and setting up temporary treatment areas.

East Nusa Tenggara police chief Rudi Darmoko said power cuts across cities and villages were hampering the flow of information and complicating the search. Teams had not yet reached Nagekeo, the area closest to the epicentre, where communications were down; roads in were blocked by landslides, and one team was attempting to reach it by ferry.

The tsunami warning

Indonesia’s Meteorology, Climatology and Geophysics Agency issued a tsunami warning for parts of East Nusa Tenggara, West Nusa Tenggara, South Sulawesi and Southeast Sulawesi, urging people away from beaches and riverbanks. Waves of less than one metre were recorded in several areas.

The warning was later lifted after monitoring showed no sea-level changes posing a threat to coastal communities. We explain how those warnings are issued and withdrawn in a separate piece — the short version is that a warning being cancelled is the system working, not a false alarm.

Why Flores

Indonesia sits on the Pacific Ring of Fire, the arc of fault lines and volcanoes around the Pacific basin, and is among the most seismically active countries on earth. Its 17,000-odd islands are home to more than 270 million people, many in structures that do not perform well in strong shaking.

Flores has a particular history. In 1992 an earthquake there generated a tsunami that killed around 2,500 people. That memory is part of why people ran for high ground on Saturday morning before any official instruction reached them — and, in a shallow quake close to shore, that instinct is the thing most likely to save lives.

What to expect next

Early casualty figures in island disasters are almost always incomplete, and the pattern is predictable: the number rises as communications are restored and as teams reach places currently cut off. Nagekeo is the obvious gap. Power outages, landslide-blocked roads and severed phone links mean the areas closest to the epicentre are the last to be counted, not the least affected.

Aftershocks of this size also make damaged buildings dangerous to enter, which slows rescue work at exactly the point when speed matters most.

Sources

US Geological Survey; Indonesia’s National Search and Rescue Agency (BASARNAS) and Meteorology, Climatology and Geophysics Agency; reporting by the Associated Press, Reuters, AFP, NPR, NBC News, Al Jazeera and Rappler.