Geochemistry, climate change and... French Revolution: understanding volcanoes with Sarah Aufrère

By Laurence Gagnon

Sarah Aufrère on a field trip to MoUnt Meager

Originally from Nice, France, Sarah developed a passion and an aptitude for science in high school. She began studying geology "for fun" and soon became fascinated by volcanoes.

"Of all the sciences, volcanology was the one that really drew me in. But could I make a career out of it?" To explore this question, Sarah travelled to Guadeloupe in the Caribbean for a one-month internship. "Being in the observatory, seeing this volcano that could pose a threat to the community, taking samples, speaking to the media…overall it was just incredible." This experience helped Sarah gain clarity about her career path and led to another opportunity. The following year, she secured a placement at SFU, where she worked with Professor Glyn Williams-Jones, the Earth Sciences Department Chair and Co-director of the Centre for Natural Hazards Research. Together, with one of his students, they studied the Tseax volcano. "This volcano erupted 250 years ago, and stories about it are still being passed down among the indigenous people (...). For me, it was a really different approach to volcanology. I loved the intersection between science and indigenous culture."

After finishing her master’s degree in England, she reached out to Professor Williams-Jones, who agreed to be her thesis supervisor. "I had a great experience in British Columbia and Glyn is really amazing. We share a great connection, which is really important when pursuing a PhD."

Sarah is currently in her fourth year at SFU's Faculty of Science. She has worked on three geochemistry projects in the Garibaldi Volcanic Belt, specifically around Mount Meager. Her primary interest lies in identifying early warning signs that could indicate a potential eruption.

When Sarah began her doctorate, the pandemic prevented her from taking samples directly from Mount Meager. However, she was able to analyze samples taken by a former UBC student. "I take basalt rocks and crush them into small pieces using a machine. Since basalt is very hard to break (...) and I'm looking for crystals that are less than one millimetre in size, I use a hammer to crush it into a powder." After conducting a series of manipulations to extract and regroup olivine crystals, Sarah examines them under a microscope to understand their chemical composition, which reveals the history of the volcano. She then analyzes the data from the various samples to gain a better understanding of Mount Meager’s behaviour. This volcano’s last eruption was 2,400 years ago. "This may seem like a long time, but on the geological time scale it's pretty recent, and this eruption was comparable to that of Mount St. Helens in 1980."

What about the impact of climate change on volcanoes and the risk of eruption? Sarah tells us that volcanoes capped by a glacier could be more vulnerable to climate change. If the glacier melts, "it will remove a significant amount of weight from the volcano, which could cause the magma trapped inside to suddenly rise up, thus triggering an eruption."

Volcanic eruptions could also have a cooling effect on the climate. Sarah provides an example deeply rooted in her French culture: "Before the French Revolution in 1789, there was a massive volcanic eruption (...) that caused a thick cloud of ash to cover almost the entire planet." As a result, the sun's rays were blocked and the Earth’s temperature dropped significantly. "The ground cooled, crops failed and famine spread, which contributed to the outbreak of the Revolution!"

It is unlikely that we will witness a volcanic eruption in the coming decades, but there is still a possibility. "There are eruptions that we can't predict. Canada’s entire west coast is situated in a volcanic zone. The biggest problem is that people are unaware of the presence of volcanoes nearby and the possibility of eruptions." Sarah reassures us, pointing out that "the government is taking steps to establish volcano monitoring systems. So with a bit of luck, if an eruption were to occur, we could anticipate it."

Sarah's interest in popularizing science led her to participate in the Western Final of the “My Thesis in 180 Seconds” on March 28. During the competition, she presented her thesis titled "Olivine time-capsules constrain the pre-eruptive history of Holocene basalts, Mount Meager Volcanic Complex, British Columbia, Canada" and won first place. As a result, she will have the opportunity to represent SFU during the National Final on May 15 at the University of Ottawa. We wish her the best of luck!