Mt. Bagana: Young and energetic

Bougainville Island in Papua New Guinea is home to three impressively large volcanoes, of which Mount Bagana, pictured here, is very active.

Since scientists discovered this volcano in 1840, its activity has continued uninterrupted, as evidenced by steady lava flows down the slopes of the volcano. Over the past 300 to 500 years, these factors have caused Mount Pagana to grow to a staggering 1,850 meters in height – making it one of the smallest and yet the most active volcanoes in the South Pacific.

NASA’s satellite image of the volcano on May 28, 2022 shows a strong eruption phase in the past 20 years: recent lava flows appear sepia in the image and partially extend into the surrounding dark green forest. It is possible that the vegetation cover in the light brown areas was destroyed by the volatile rocks and toxic gases. In contrast, lava flows have already been recovered long ago by the Papua New Guinean flora and are shown in light green.

Mount Bagana not only emits large amounts of lava, but also thousands of tons of sulfur dioxide daily – more than any other volcano without a lava lake in the world. Pagana owes its constant volcanic activity to its geological location on the boundary of a particularly active plate, because in the southwest Pacific two continental plates move towards each other at a speed of about eleven centimeters per year.

This slow collision causes one plate to slide under the other. The associated forces created a deep-sea trench on the lower plate of the Earth, while ascending magma at this interface of the Earth formed volcanoes on the upper plate. The Pacific and Australian plates have been in a so-called subduction process for millions of years, resulting in the igneous rocks of Bougainville Island and later the formation of the Bagana volcano.

© wissenschaft.de – Josephine Frank