Ice-capped volcanoes slower to erupt, study finds —


The Westdahl Peak volcano in Alaska final erupted in 1992, and continued growth hints at one other eruption quickly. Specialists beforehand forecasted the subsequent blast to happen by 2010, however the volcano — positioned beneath about 1 kilometer of glacial ice — has but to erupt once more. Utilizing the Westdahl Peak volcano as inspiration, a brand new volcanic modeling research examined how glaciers have an effect on the soundness and short-term eruption cycles of high-latitude volcanic programs — a few of which exist alongside main air transportation routes.

The research, led by College of Illinois Urbana-Champaign undergraduate researcher Lilian Lucas, with graduate scholar Jack Albright, former graduate scholar Yan Zhan and geology professor Patricia Gregg, used finite factor numerical modeling to review the soundness of the rock that surrounds volcanic programs — however with a brand new twist. The staff accounted for the extra strain from glacial ice volcanoes when forecasting the timing of eruptions.

“Volcanic forecasting entails a whole lot of variables, together with the depth and measurement of a volcano’s magma chamber, the speed at which magma fills that chamber and the energy of the rocks that comprise the chamber, to call a couple of,” Lucas stated. “Accounting for overlying strain from polar ice caps is one other vital, but poorly understood, variable.”

The Westdahl Peak volcano, positioned alongside the Aleutian Island chain in western Alaska, serves as an ideal mannequin for research as a result of it’s effectively instrumented and constantly monitored by the Alaska Volcano Observatory, the researchers stated.

“The Aleutian Islands are pretty distant, however they lie alongside a serious air transportation and commerce route connecting North America and East Asia,” Albright stated. “Volcanic ash within the environment is hazardous to plane engines and may trigger main disruptions in air visitors, so extra correct forecasting — even on the dimensions of months — can present vital security data for air visitors and close by inhabitants.”

To find out how overlying strain from polar ice can have an effect on the timing of eruptions, the staff ran laptop simulations of magma reservoirs of various shapes and sizes, the research reported. Researchers diverse the flux, or quantity of magma that enters the system from under, to find out when the corresponding strain exceeds the energy of the encompassing rock, which can trigger rock failure resulting in an eruption.

“We then insert parameters for various thickness of ice into every mannequin situation and evaluate how lengthy it takes to succeed in that time of failure with and with out ice,” Albright stated.

The research reported that relative to the time it ought to take for Westdahl Peak to erupt with out glacial ice, the presence of ice will enhance the soundness of the magma system and delay the eruption date by roughly seven years.

“Extra particularly, the fashions with out the presence of the confining strain of the ice cap calculated a time to eruption of about 93 years,” Lucas stated. “Including a 1-kilometer-thick ice cap to the mannequin then will increase the eruption date to roughly 100 years. Fashions are usually not an ideal instrument to make use of in forecasting future eruptions, nevertheless, we’re primarily within the enhance on this time on account of the elevated ice load.”

On the whole, the research outcomes indicated that ice thicknesses of 1 to three kilometers can delay ice-covered volcano eruptions for years to a long time.

“These will increase in time could appear insignificant on a geologic scale, however it’s vital on the human time scale,” Gregg stated. “Going ahead, it is going to be necessary to account for glacial ice cowl in future forecasting efforts.”

The staff acknowledged that earlier research thought of how seasonal modifications akin to annual snow cowl would possibly have an effect on the eruption interval of volcanoes. Nonetheless, in comparison with the entire overlying load that the magma chamber should overcome to erupt, small seasonal differences are unlikely to play a serious function for many programs.

“Seasonal ice loss might impression eruption timing for programs near failure,” Zhan stated. “Moreover, it is going to be necessary to think about how local weather change and glacial ice soften would possibly impression Westdahl Peak and different high-latitude volcanoes sooner or later.”

The outcomes of the research are printed within the journal Frontiers in Earth Science. The Nationwide Science Basis, NASA and the College of Illinois Division of Geology Summer season Undergraduate Analysis Alternative Program supported this research.