The Westdahl Peak volcano in Alaska last erupted in 1992, and continued expansion hints at another eruption soon. The volcano, located under about 1 kilometer of ice, has yet to erupt again despite experts' predictions. A new volcanic modeling study looked at how glaciers affect the stability and short-term eruption cycles of high-latitude volcanic systems.
The study, led by University of Illinois geology-Champaign undergraduate researcher Lilian Lucas, used finite element numerical modeling to study the stability of the rock that surrounds volcanic systems, but with a new twist. The team accounted for the extra pressure from glaciers when forecasting eruptions.
Lucas said that volcanic forecasting involves a lot of variables, including the depth and size of a volcano's magma chamber, the rate at which magma fills that chamber and the strength of the rocks that contain the chamber.
The Westdahl Peak volcano, located along the Aleutian Island chain in western Alaska, is a great model for study because it is well instrumented and continuously monitored by the Alaska Volcano Observatory.
The Aleutian Islands lie along a major air transportation and trade route connecting North America and East Asia.
The team ran computer simulations of different sizes and shapes of magma in order to figure out how the pressure from polar ice affects the timing of eruptions. Researchers varied the amount of magma that enters the system from below to determine when the pressure exceeds the strength of the surrounding rock, which may cause rock failure and lead to an eruption.
Albright said that they put parameters for different thickness of ice into each model scenario and compare how long it takes to reach that point of failure with and without ice.
According to the study, the presence of ice will increase the stability of the magma system and delay the eruption by seven years.
Lucas said that the models without the ice cap calculated a time to eruption of 93 years. We are interested in the increase in this time as a result of the increased ice load because models are not a perfect tool to use in forecasting future eruptions.
The study showed that ice thicknesses of 1 to 3 kilometers can delay volcanic eruptions for a long time.
It is significant on the human time scale that these increases in time seem insignificant on a geologic scale.
The team acknowledged that previous studies had looked at how snow cover might affect the eruption interval of volcanoes. Small seasonal variations are unlikely to play a major role for most systems when compared with the total overlying load that the magma chamber must overcome to erupt.
Zhan said that seasonal ice loss may impact eruption timing for systems close to failure.
The results of the study can be found in the journal.
More information: Lilian C. Lucas et al, The Impact of Ice Caps on the Mechanical Stability of Magmatic Systems: Implications for Forecasting on Human Timescales, Frontiers in Earth Science (2022). DOI: 10.3389/feart.2022.868569. www.frontiersin.org/articles/1 … art.2022.868569/full Citation: Ice-capped volcanoes slower to erupt, study finds (2022, May 10) retrieved 10 May 2022 from https://phys.org/news/2022-05-ice-capped-volcanoes-slower-erupt.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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