Mount Agung, a volcano in Indonesia, is likely to erupt soon, say geologists. The Indonesian government has ordered the evacuation of 100,000 people in a six-mile radius around the volcano, which has the potential to erupt on a scale similar to the 1980 eruption of Mount St. Helens in Washington. Mount Agung's last eruption in 1963 killed 1,100 people.
University of Michigan experts are available to discuss the phenomenon.
Ben van der Pluijm is the Bruce R. Clark Collegiate Professor of Geology and professor of the environment who studies how geohazards affect society. His research areas are tectonics (dealing with geologic transformations of Earth's crust), and hazards geology and societal resilience (dealing with planet-human interactions).
"Mount Agung's explosive volcanism is directly related to plate tectonics in the Indonesian region, and is located at the Australian-Eurasian plate boundary," van der Pluijm said. "Eruption reflects melting from plate interactions at depth that works its way to the surface as an eruption. When it erupts, there will be rocks and ash barreling out into the sky, and the flow of ash down its slopes will kill everything in its way, like Italy's Mount Vesuvius did to Pompeii.
"Volcanic ash moving high into the stratosphere can also temporarily affect temperature conditions where it blocks some sunlight from reaching the surface. It also limits air travel, as plane engines become damaged from these small particles mixed with air."
Joyce Penner, the Ralph J. Cicerone Distinguished University Professor of Atmospheric Science, studies small volcanic airborne particles known as sulfate aerosols, which can form at high altitude from the sulfur dioxide emitted by volcanoes. Sulfate aerosols can scatter radiation, and thus cool the atmosphere.
"The actual climate impact of the volcanic emissions depends on the altitude of injection," Penner said. "The 1963 Agung eruption was energetic enough to put sulfur dioxide into the stratosphere, where, after forming sulfate particles, caused cooling for several years. If the emissions stay within the troposphere, their impact is much shorter lived and probably not detectable, unless the eruption continues for a time. I saw one report that said the ash plume reached nine kilometers, which might be just at the edge of entering the stratosphere at the latitude of Bali."
Adam Simon is a geologist with a research focus on volcanoes and natural resources that form in volcanic systems and an associate professor of earth and environmental sciences.
"As magma inflates in the chamber beneath the volcano, it is like a bottle of champagne shaken vigorously with the cork still on," Simon said. "Bubbles of carbon dioxide form within the liquid in the bottle, and they exert a force outward on the bottle and the cork. Once sufficient overpressure is generated, the cork will blow off and the champagne erupts. This is analogous to what happens over the days to weeks to months prior to a volcano eruption.
"The ground's shaking leading up to the eruption can also cause mudslides, called lahars, that devastate local communities as the mud rushes down the slopes of the volcanoes faster than humans can escape. After this eruption, Agung will return to a dormant phase and will certainly erupt again. The success at Agung of using ground-level earthquake sensing technology to forecast eruptions in time to evacuate humans speaks to the need for all active volcanoes to have such technology installed around the perimeter of the volcano."
Sue Anne Bell, clinical associate professor of nursing, is an expert on the health effects of disasters and the impact of climate change on human health. She is interested in the long-term impact of disasters on women's health, and has practiced nursing and conducted research in Africa, Asia and the Caribbean.
"The public perception of a volcano eruption is of molten lava and ash decimating communities in its wake," Bell said. "While these ideas are not completely unfounded, in reality, the immediate health threats of the Mount Agung volcano are related to ash from the volcano worsening existing chronic respiratory conditions. Those most likely to be affected are the populations who are already the most vulnerable, such as older adults and those living with disabilities."