Mount Ontake in Japan rises 3,067 meters above sea level — a windswept giant standing head and shoulders above densely forested hills. This ancient volcano is a popular trekking site. A trail traverses its ash- and boulder-strewn ridges. There are several huts and a shrine. On September 27, 2014, hikers took advantage of a blue sky and gentle wind. At 11:52 a.m., over a hundred of them stood on the summit, eating snacks and taking photos. Disaster struck with little warning.
The windows and doors of a nearby hut rattled, vibrated by a low-frequency shock wave inaudible to humans.