In 2021, Alaska’s Veniaminof volcano surprised scientists with an explosive eruption that launched ash 15 kilometers into the atmosphere. Disturbingly, the eruption went undetected for three days after it began, a phenomenon not uncommon among certain types of volcanoes.
A recent study published in Frontiers in Earth Science provides insight into why some eruptions occur without the typical indicators many rely on for early warnings, such as ground deformation or seismic activity.
Dr. Yuyu Li, a volcanologist from the University of Illinois and the study’s lead author, emphasizes the potential hazards of these stealthy eruptions. “Some of these volcanoes are located near major air routes or close to communities,” he pointed out, citing examples like Mexico’s Popocatépetl and Colima, Indonesia’s Merapi, Colombia’s Galeras, and Italy’s Stromboli.
The researchers focused specifically on Veniaminof’s ambiguous 2018 eruption despite constant monitoring, which yielded no clear warning signals. By analyzing three years of pre-eruption data, they developed a model demonstrating how magma dynamics underground translate into detectable changes at the surface or lack thereof.
Their findings reveal that how magma enters a volcano’s underground chamber is crucial in determining whether an eruption will produce warning signs. A rapid influx of magma generally leads to ground swelling or shaking, providing clear indicators of an impending eruption. Yet, if magma enters a small chamber slowly, the scenario changes significantly.
In cases where a small quantity of magma flows into a small chamber, a stealthy eruption becomes much more probable. This situation aligns closely with the characteristics scientists have observed at Veniaminof, which possesses a small magma chamber and experiences slow magma flow.
The eruption warning signals are also influenced by the shape and size of the magma chamber. Larger, flatter chambers may produce only minor earthquakes while smaller, more elongated chambers tend not to induce noticeable ground swell. According to the study, stealthy eruptions are most likely when multiple conditions combine: slow magma flow, small magma chamber size, and specific chamber shapes and depths.
Another critical factor outlined in the research is temperature. If the surrounding rock remains warm because of the consistent presence of magma, it is less likely to crack or shift, which would typically alert scientists to an impending eruption. In these warm environments, the traditional warning signs—such as seismic activity—are less likely to manifest, complicating efforts to predict such eruptions.
To address the risks associated with these stealthy eruptions, the research team advocates for enhanced monitoring techniques. They suggest integrating high-precision instruments like borehole tiltmeters, strainmeters, fiber optic sensing, as well as emerging methods like infrasound monitoring and gas emission analysis.
Li also highlights the potential of machine learning technologies in detecting subtle changes in volcanic behavior, particularly in picking out earthquake signals more effectively.
The implications of this research extend beyond Veniaminof. The findings indicate similar challenges at Colombia’s Galeras and Italy’s Stromboli, where traditional methodologies of monitoring seismic activity often miss the mark, putting millions at risk.
The study’s predictive model combines real-time data and physical models, offering the possibility of forecasting stealthy eruptions hours or even days in advance. Despite certain challenges, like the deployment of expensive sensors in remote locations, the effort promises significant benefits.
Improvement in early warning systems could lead to saving lives and minimizing economic fallout resulting from ash clouds affecting air travel.
“In the future, this approach could improve monitoring of these elusive volcanic systems, leading to more efficient responses that protect nearby communities,” Li concluded.
image source from：https://thedebrief.org/this-stealthy-ancient-volcano-in-alaska-erupts-without-warning-scientists-think-they-now-know-why/
