Непал: 7 минут до катастрофы. Что произошло на самом деле

At first the whole world decided that a magnitude 5.2 earthquake had struck northern Nepal. Seismic stations on the far side of the planet recorded the tremor, the news feeds went out with that wording - and almost everything in it turned out to be wrong. Underground, at that moment, absolutely nothing happened: the plates did not shift, no fault ruptured, there was no focus at all. The signal was generated by the mountain itself. In this investigation we take apart the disaster in the valley of the Lhende river beneath the Langtang Lirung massif using open data: satellite image archives, the catalogue of seismic events, chance drone videos and eyewitness photographs. Three main questions. First: why calling what happened a "glacier collapse" is wrong - the detachment plane runs down into bedrock, which means rock failed, and the ice simply rode on top as a load. Second: where all that water came from if the upper hanging glacier was far too small - the answer lies below, under the impact site, where fifteen years of satellite images show a second glacier buried under debris. Third: what the second seismic signal of magnitude 4.2 was that the instruments recorded three hours after the first, and why almost nobody reported it. We go through the geology of gneisses and leucogranites up to 34 million years old, the mechanics of an ice-rock avalanche, fluidization, the entrainment of material that makes the flow more terrifying the farther it travels, a speed of around 160 km/h and the undercutting of the slope that produced the second collapse. We show why exactly this combination - a hanging glacier, rock shattered by tectonics, a glacier below, a road and villages - occurs hundreds of times across the Himalayas. Distance here is measured not in kilometres but in time. This time there were seven and a half minutes of it.