Detailed aerial images of Mt. Iou fumaroles captured by drone

Volcanic smoke rises vigorously from Atosanupuri (Mt. Iou) in the town of Teshikaga in eastern Hokkaido. On September 16, with the help of a local guide, we climbed the mountain – the focal point of Akan-Mashu National Park and what is said to be the source of the Kawayu Onsen hot springs – to photograph the volcanic crater using a drone. The beautiful lemon-yellow fumarole was visible from the drone.

Atsanupuri has been off limits for many years but, as of autumn 2019, it is now possible to enter the mountain only on a determined route with an authorized guide. On this day, we were guided by Mr. Fujiwara of the e Teshikaga EcoMachi Promotion Conference.

The air is filled with the smell of sulfur, and the route is dotted with small fumaroles. “Be careful not to step into them,” warns Mr. Fujiwara. The explosion crater, commonly known as ‘bear drop’ located at an altitude of approximately 350 meters, is said to have been created by an eruption hundreds of years ago. The cliffs that rise vertically for more than 200 meters to the summit speaks of the intensity of the eruption. Steam spouts violently from the fumarole known as ‘F1’ that can be seen from the foot of the mountain.

To climb the mountain, it is necessary to reserve a Lake Mashu Tourism Association guide.

Steam spouts violently from the F1 fumarole, which was filmed using a drone
The explosion crater that speaks of the intensity of the eruption (commonly known as ‘bear drop’)


Atosanupuri (Mt. Iou)