Dr. Darcy Cordell delivered a public lecture on volcanoes at Athabasca University on Thursday, Oct. 29, according to TownAndCountryToday.com. The talk was his second Science Outreach – Athabasca presentation this year, and it covered both why volcanoes deserve scientific attention and how geophysical tools are used to map what lies beneath them.
Cordell opened by acknowledging the obvious appeal of his subject, telling the audience that volcanoes are worth studying partly because they are fascinating, the outlet reported. He used a Hawaiian volcano as an illustration.
Why it matters
The practical case for the research is harder to dismiss. According to TownAndCountryToday.com, Cordell said volcanoes kill roughly 500 people around the world each year on average. Large eruptions also ripple outward in ways that reach far beyond the slopes of the mountain itself.
He cited the 2010 eruption of Eyjafjallajökull, which grounded more than 100,000 flights across Western Europe, the outlet reported. The disruption showed how an event in one region can stall air travel across a continent.
Cordell also explained that scientists assess what kind of eruption to expect by looking at the lava itself. Runny, fluid lava tends to flow and presents a comparatively lower risk, while thicker lava can produce violent blasts of the kind seen at Mount St. Helens in 1980, according to the report.
He noted that certain volcanoes are capable of far larger events still, with consequences for the planet's climate and its ability to support life.
Tambora, Yellowstone and the reach of ash
The lecture drew on historical examples to show how far volcanic effects can travel. Cordell described Mount Tambora in Indonesia, whose 1815 eruption is the biggest recorded in human history, TownAndCountryToday.com reported. The blast carved a crater seven kilometres wide on the island, and the sulfur dioxide and ash it threw into the atmosphere pushed global temperatures down, producing what became known as "The Year Without Summer" in 1816.
He then turned to super volcanoes such as Yellowstone. About 640,000 years ago, the Yellowstone Caldera ejected an estimated 1,000 cubic kilometres of material, according to the outlet. A researcher-produced simulation of ash depth indicated that the event would have laid down 100 millimetres of ash as far away as Athabasca — enough, Cordell said, to bring down a roof.
That detail tied the global subject back to the local audience, framing a distant caldera as something with a measurable connection to northern Alberta.
Tracking magma at Laguna del Maule
The second half of the talk shifted to Cordell's own doctoral work at Laguna del Maule, a volcano in central Chile. Reaching the site required horses, helicopters, trucks and a boat, and the team used those means to measure the earth's magnetic and electrical fields, then calculated from those readings where magma sat underground, according to TownAndCountryToday.com.
Laguna del Maule stands out because it has shown signs of unrest since 2007. The ground there has been swelling upward, a change that can precede an eruption. Cordell described the scale of the movement to the audience, saying the surface at the location has risen by about two metres, which he called remarkable.
Applying a geophysical technique known as magnetotellurics, Cordell and his colleagues found that the volcano's magma body is both large and deep, and that it sits offset from the volcano itself — a result the team had not anticipated, the outlet reported.
Cordell's assessment is that the system has generated a substantial volume of supercritical fluid, a substance held above its critical temperature that behaves as neither gas nor liquid. In his view, that would likely make any future eruption more explosive than gently effusive.
He closed with a word on the nature of the work itself, describing fieldwork as demanding and difficult but also a genuine adventure, according to TownAndCountryToday.com.
The lecture formed part of the Science Outreach – Athabasca series, which brings researchers to the university to present their work to the public. Cordell's appearance was his second with the program this year.
What to watch next: whether Laguna del Maule's ongoing ground deformation continues at its current pace, and how magnetotelluric surveys are applied to other restless volcanoes where the subsurface structure is still poorly understood.
