NASA Satellite Image Shows 'Parasitic' Volcano Cones In Hokkaido

In northeastern Hokkaido, there is a volcano that has a parasitic cone, which also has a parasitic cone of its own. NASA's Landsat 8 satellite captured the interesting volcanic features using the Operational Land Imager.

Typically, volcanoes have a central vent that is connected to an underground magma chamber. This central vent is usually where most of the magma will pass but, sometimes, the central vent is plugged and pressure builds up, forcing the magma and gas to find other ways of reaching the surface. This could result in smaller, secondary volcanoes called parasitic cones that can sometimes also become large volcanoes.

Such is the case in northeastern Hokkaido where the Kussharo caldera has the parasitic cone Mashū caldera, which also has its own parasitic cone, Mount Kamui. In the natural-color image taken by Landsat 8 last Sept. 27, 2019, the parasitic cones and calderas can clearly be seen within the Akan-Mashū National Park, one of the oldest national parks in Japan.

"The image also highlights calderas, the bowl-shaped volcanic basins that form when volcanoes erupt explosively or when the top of a volcano slumps into an empty or partly empty magma chamber," NASA notes. "Since they are often enclosed by steep cliffs and lack outlets for water to run off, calderas often fill up with lakes."

Of the volcanic features, Kussharo is the oldest, having formed between 340,000 and 30,000 years ago. The Mashū caldera then formed about 7,000 years ago after a major eruption then, Mount Kamui formed after an eruption that happened about 1,000 years ago.

Kussharo has the largest caldera in Japan but it only has a few fish because of its acidic waters. Lake Mashū, on the other hand, is one of the clearest lakes in Japan because it has no inlets or outlets.

Other examples of volcanoes with parasitic cones are Mt. Etna in Sicily, which has over 200 parasitic cones, Jeju Island in South Korea, which has multiple parasitic cones around Mount Halla and, Piton de la Fournaise on Réunion Island in the Indian Ocean, which is one of the most active volcanoes in the world.