Papua New Guinea sits at one of the most active tectonic junctions on Earth. Here, the Australian Plate grinds northeast against the Pacific Plate, and between them a clutter of microplates - the South Bismarck, the Solomon Sea, the Woodlark - twists and slips in ways that generate more than 100 earthquakes of magnitude five or greater every year. The September 2022 quake was slightly unusual. It happened at intermediate depth, 61 kilometers down, within a subducted slab of ocean crust rather than at the plate boundary itself. Deep-focus events tend to cause less surface destruction than shallow ones of equivalent size, but they shake over wider areas. That is why the quake was felt in Merauke, Jayapura, and Wamena across the border in Indonesia, and in places where it should have been too far to feel.

Eleven of the dead were in Morobe Province, closest to the epicenter. Five died in Madang Province, five more in the Eastern Highlands. Three miners were killed at Wau, a gold-mining town perched among steep ridges where landslides have always been part of the bargain. In the Nawae District, a rockfall killed four including one man buried under loose stones. Kabwum lost three. Rai Coast District lost one to a landslide in the mountains. Forty-two others were injured. The pattern told a familiar story in Papua New Guinea: earthquakes here do not kill through the shaking itself so much as through the mountainsides they bring down. Most homes in the rural villages - constructed of bush materials, light and flexible - rode out the shaking intact. What killed was the earth above them.

The Ramu hydropower station at Kainantu took damage that knocked out electricity across Madang and Morobe Provinces. The Highlands Highway - the single road that connects the interior to the coast at Lae - cracked at Markham and Ramu. Submarine telecommunications cables running from Port Moresby to Madang and from Port Moresby to Sydney both suffered damage simultaneously, cutting internet services to the Highlands, the Islands Region, and the Momase. At the University of Goroka, a seven-story dormitory split with cracks so severe that students were barred from re-entering. Window awnings dropped. Ten students were hurt. More than 150 were displaced, resettled temporarily in the villages of Okiyufa, Asariufa, and North Goroka - or in classrooms when nothing else was available. The country's modern infrastructure, much of it built over the last forty years on foundations that assumed less severe shaking than what the geology here actually delivers, had been caught off-guard.

In July 2022 - two months before the earthquake - a research article published in The Conversation carried the blunt title "Not if, but when: unless Papua New Guinea prepares now, the next big earthquake could wreak havoc in Lae." The authors were right about the timing and almost right about the place. Their warning drew on a decade of tectonic studies showing that Lae and the surrounding Morobe region were overdue for a significant event. PNG's seismic hazard maps, first developed in 1982, had underestimated real risk for years. Most buildings across the country - including in Lae, Madang, and Port Moresby - are constructed of masonry without proper seismic detailing. The modern building code was based on outdated assumptions. When the September quake arrived, it delivered its message against old knowledge the country had not yet updated its buildings to match.

Mission Aviation Fellowship - a small-plane flying service that has served PNG's remote communities for decades - flew aerial surveys above Morobe Province in the days after the quake, mapping landslides and trying to determine which villages were cut off. Many communities in the rural mountains waited days to be reached. The Morobe Provincial Disaster Director, Charley Masange, coordinated what assistance could be assembled. In Kabwum, local authorities admitted they could not help much because the 2022 Papua New Guinean election had ended in violence that had destroyed the government buildings they would have used. A total of 1,076 houses were damaged or destroyed. Across Madang city, 389 homes were flattened. Ten million kina was allocated for relief. Private pilots and volunteers brought food to survivors the roads could not reach. The country, shaken and grieving, did what Papua New Guinea so often has to do after these events: looked after its own, over distances the rest of the world would not consider survivable, and carried on.