The Sakurajima volcano in Japan last erupted in 1914 killing 58 people and caused widespread flooding in the nearby city of Kagoshima.
The volcano, however, could erupt again in the next few decades as the pool of liquid magma that swells beneath it grows each year, indicating a looming large eruption.
A team of researchers developed a new method for imaging the underground plumbing system of Sakurajima, one of the most active volcanoes in Japan.
Using GPS deformation measurements and 3D computer models, the researchers assessed the buildup beneath Sakurajima volcano and found that the reservoir of magma grows at a significant rate. They found that 14 million cubic meters (494 million cubic feet) of magma accumulate every year, which is enough to fill the Wembley Stadium three-and-a-half times over.
Based on their findings, the researchers said that it would take 130 years from the volcano's last major eruption for the next one to happen. This means that the region is due for a major eruption about 2044, which is about 25 years from now.
Although the Sakurajima volcano remained constantly active over the last several decades, the small regular volcanic eruptions were not able to get rid of all the magma and the Aira caldera — deep crater that was formed from a collapsed magma chamber. It now serves as a shallow reservoir for Sakurajima's magma and is being filled faster than the rate magma is released through small eruptions. This means that pressure is building up.
"Using the example of continued inflation at Aira caldera, Japan, we demonstrate that magma is accumulating faster than it can be erupted, and the current uplift is approaching the level inferred prior to the violent 1914 Plinian eruption," the researchers reported in their study, which was published in the journal Scientific Reports on Sept. 13.
"[T]he inferred magma supply rate indicates a ~130-year timeframe to amass enough magma to feed a future 1914-sized eruption."
Although it is not possible to accurately predict when a volcano would erupt, the researchers said that the result of their study should help authorities plan for future disasters not just in Japan but also in other places worldwide.
"The numerical constraints we were able to put on the magma supply conditions can also be used to assist with probabilistic and quantitative eruption forecasting," said study researcher James Hickey, from the School of Earth Sciences at the University of Bristol in the UK.
