MSGID: 1:317/3 6279ead9   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Ice-capped volcanoes slower to erupt, study finds    
      
     Date:   
         May 9, 2022   
     Source:   
         University of Illinois at Urbana-Champaign, News Bureau   
     Summary:   
         The Westdahl Peak volcano in Alaska last erupted in 1992, and   
         continued expansion hints at another eruption soon. Experts   
         previously forecasted the next blast to occur by 2010, but the   
         volcano -- located under about 1 kilometer of glacial ice --   
         has yet to erupt again. Using the Westdahl Peak volcano as   
         inspiration, a new volcanic modeling study examined how glaciers   
         affect the stability and short-term eruption cycles of high-   
         latitude volcanic systems -- some of which exist along major air   
         transportation routes.   
      
      
      
   FULL STORY   
   ==========================================================================   
   The Westdahl Peak volcano in Alaska last erupted in 1992, and continued   
   expansion hints at another eruption soon. Experts previously forecasted   
   the next blast to occur by 2010, but the volcano -- located under about   
   1 kilometer of glacial ice -- has yet to erupt again. Using the Westdahl   
   Peak volcano as inspiration, a new volcanic modeling study examined   
   how glaciers affect the stability and short-term eruption cycles of   
   high-latitude volcanic systems - - some of which exist along major air   
   transportation routes.   
      
      
   ==========================================================================   
   The study, led by University of Illinois Urbana-Champaign undergraduate   
   researcher Lilian Lucas, with graduate student Jack Albright, former   
   graduate student Yan Zhan and geology professor Patricia Gregg, 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 additional pressure from glacial ice volcanoes when forecasting   
   the timing of eruptions.   
      
   "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,   
   to name a few," Lucas said.   
      
   "Accounting for overlying pressure from polar ice caps is another   
   critical, yet poorly understood, variable."  The Westdahl Peak volcano,   
   located along the Aleutian Island chain in western Alaska, serves as a   
   great model for study because it is well instrumented and continuously   
   monitored by the Alaska Volcano Observatory, the researchers said.   
      
   "The Aleutian Islands are fairly remote, but they lie along a major air   
   transportation and trade route connecting North America and East Asia,"   
   Albright said. "Volcanic ash in the atmosphere is hazardous to aircraft   
   engines and can cause major disruptions in air traffic, so more accurate   
   forecasting - - even on the scale of months -- can provide critical safety   
   information for air traffic and nearby inhabitants."  To determine how   
   overlying pressure from polar ice can affect the timing of eruptions,   
   the team ran computer simulations of magma reservoirs of different   
   sizes and shapes, the study reported. Researchers varied the flux, or   
   amount of magma that enters the system from below, to determine when   
   the corresponding pressure exceeds the strength of the surrounding rock,   
   which may cause rock failure leading to an eruption.   
      
      
      
   ==========================================================================   
   "We then insert 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," Albright said.   
      
   The study reported that relative to the time it should take for Westdahl   
   Peak to erupt without glacial ice, the presence of ice will increase the   
   stability of the magma system and delay the eruption date by approximately   
   seven years.   
      
   "More specifically, the models without the presence of the confining   
   pressure of the ice cap calculated a time to eruption of about 93 years,"   
   Lucas said.   
      
   "Adding a 1-kilometer-thick ice cap to the model then increases the   
   eruption date to approximately 100 years. Models are not a perfect tool   
   to use in forecasting future eruptions, however, we are mainly interested   
   in the increase in this time as a result of the increased ice load."   
   In general, the study results indicated that ice thicknesses of 1 to 3   
   kilometers can delay ice-covered volcano eruptions for years to decades.   
      
   "These increases in time may seem insignificant on a geologic scale, but   
   it is significant on the human time scale," Gregg said. "Going forward, it   
   will be important to account for glacial ice cover in future forecasting   
   efforts."  The team acknowledged that previous studies considered how   
   seasonal changes such as annual snow cover might affect the eruption   
   interval of volcanoes.   
      
   However, when compared with the total overlying load that the magma   
   chamber must overcome to erupt, small seasonal variations are unlikely   
   to play a major role for most systems.   
      
   "Seasonal ice loss may impact eruption timing for systems close to   
   failure," Zhan said. "Furthermore, it will be important to consider how   
   climate change and glacial ice melt might impact Westdahl Peak and other   
   high-latitude volcanoes in the future."  The results of the study are   
   published in the journal Frontiers in Earth Science. The National Science   
   Foundation, NASA and the University of Illinois Department of Geology   
   Summer Undergraduate Research Opportunity Program supported this study.   
      
      
   ==========================================================================   
   Story Source: Materials provided by   
   University_of_Illinois_at_Urbana-Champaign,_News_Bureau.   
      
   Original written by Lois Yoksoulian. Note: Content may be edited for   
   style and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Lilian C. Lucas, John A. Albright, Patricia M. Gregg, Yan Zhan. The   
         Impact of Ice Caps on the Mechanical Stability of Magmatic Systems:   
         Implications for Forecasting on Human Timescales. Frontiers in   
         Earth Science, 2022; 10 DOI: 10.3389/feart.2022.868569   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2022/05/220509162452.htm   
      
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