In September, a 6.7 magnitude earthquake struck Japan’s northernmost main island, Hokkaido. Only days before, Typhoon Jebi had soaked the area, including the town of Atsuma where the soil contains a loosely structured layer of volcanic ash. It was a deadly combination.
The intense precipitation increased the water pressure within the soil, which can lead to landslides, according to Kyoji Sassa, a Kyoto University expert in soil mechanics.
Another trigger? The shear stress caused by earthquakes. Atsuma experienced both, causing hillsides to collapse throughout the region in a matter of hours. The devastation, visible throughout this image, stretched for several square miles. According to Japan’s Fire and Disaster Management Agency, 41 people died; 36 were in Atsuma.