The indigenous Aynu people regarded this volcanic island as the sacred Home of the Thunder God
. While this island is not large enough for permanent settlements, the seafaring Aynu tribes from the larger islands of this volcanic archipelago made a treacherous pilgrimage to this island every summer. It is speculated that this pilgrimage was meant as a way to appease the God who was likely associated with thunder not only because of the similar noise that volcanoes make during explosive eruptions, but also because of the ground shaking and rumbling noises made by the numerous, strong earthquakes that occur frequently throughout the archipelago. What's more, the strongest of these earthquakes often trigger volcanic eruptions which, in turn, would reinforce a positive correlation between these events.
There are four (4) lava domes located within this caldera; the two in the foreground are relatively brand new, having formed within the past 250 years. The whitish area along the caldera shoreline (center left) is a cluster of strong fumaroles (volcanic gas vents) and hot springs; the steam and gasses associated with this activity can be seen rising upwards. The caldera bay floor, which is only 30-40 m deep, has numerous locations of underwater volcanic activity (as witnessed by divers), and one can often see areas of gas bubbles on the water's surface.
More info about this volcano can be found here (from the Global Volcanism Program website): Usasyr
This photo is one of a series that I took during an expedition to a large chain of volcanic islands that separate the Sea of Okhotsk from the northwestern Pacific Ocean. Please see the corresponding Gallery
for detailed information on the archipelago and to see the other photos from the series.