UNIVERSITY PARK, Pa. — When Judit Gonzalez-Santana conducts her research, she first looks to space. With each passing of radar satellites in the Earth’s orbit, changes in elevation of the ground at Guatemala’s Pacaya Volcano are recorded, providing data to the Penn State doctoral candidate in geosciences, who is training to become a volcanologist.

From a computer at Penn State, she’s able to piece together deformations on the surface of the volcano, such as those owing to disruptions during large eruptions in 2010 and 2014. 

It’s a sharp contrast to her recent work, where she stood just feet from a volcano on La Palma, which has been erupting for more than a month on one of Spain’s Canary Islands.

Gonzalez-Santana, who is from Gran Canaria, one of eight main Canary Islands, first heard news that the volcano was showing evidence of increased seismic activity about a week before it erupted on Sept. 19, displacing more than 5,000 residents and destroying hundreds of homes despite no confirmed loss of human life, according to the Smithsonian Institution.

She knew that the event was rare — she witnessed an underwater eruption on the Canary Islands in 2011 and her parents recalled the glow in the night sky when Teneguía Volcano erupted on the surface of La Palma in 1971 — but that the event might also be short-lived. The 2011 eruption, for example, lasted just days. This eruption turned out to be La Palma’s longest on record — dating back to 1500 — according to experts.

Gonzalez-Santana was playing soccer with her colleagues the day of the eruption when her watch exploded with messages from friends asking if she would return home to witness the event. Not wanting to let the opportunity pass to assist with monitoring of an active eruption on her home islands, she made the decision to contact the Canary Islands Volcanological Institute known as INVOLCAN — where she volunteered in 2012 — to obtain scientist-level credentials. With that, she would be able to get closer to the volcanic activity (the public is barred from going closer than 1.2 miles from the eruption) and allow her to gather helpful data and hone her skills.

Gonzalez-Santana’s 2011 experience with INVOLCAN happened while she was still in high school and convinced her of her career path. She earned a degree in 2017 from Oxford University in Earth sciences.

Gonzalez-Santana, who is advised by Penn State volcanologist Christelle Wauthier, in the InSAR, Geodesy and Geohazards lab, worked from Nov. 8 to 14 with INVOLCAN to gather data by land and by boat. At times, she joined a crew to take gas measurements about 650 feet from the eruptive vents. Other times, she took ash samples or images of the volcano’s cone using a thermal camera that could accurately capture the heat both day and night. The team wore protective gear and were cleared by a safety crew before beginning each mission, capturing data on lava flows that — at 1,500 degrees Fahrenheit — reached the ocean with bursts of steam. Sometimes a carefully placed vehicle was parked and pointed towards a safe exit.

Much of this data, Gonzalez-Santana said, can also be captured by remote sensing techniques such as satellites. But it’s often “ground-truthed” with local measurements. For someone used to seeing the data from afar, she said the experience was eye-opening and educational.

“Capturing these ground-based measurements really puts what I do into perspective. I’m used to gathering this data with ease through satellites but I miss out on seeing the processes,” Gonzalez-Santana said. “Now, when I look at my data, I can imagine what’s happening on the surface. It’s valuable for scientists who use remote sensing techniques to get to see these events in the field.”

Using a grant from NASA, Gonzalez-Santana uses techniques such as InSAR — or Interferometric Synthetic Aperture Radar — to study the flank instability of Pacaya Volcano. The satellite sends microwave radiation to the Earth’s surface and back and can spot minute changes in the ground. Using this data, Gonzalez-Santana uses computational modeling to figure out the sources of the ground deformation.

This information can improve what we know about how volcanoes change over time and also help us better forecast when they’ll erupt. These advances, said Gonzalez-Santana, are evident with instances such as La Palma, where residents were evacuated in advance of the eruption.

For this eruption, some of the remote sensing techniques Gonzalez-Santana uses also observed the ground swelling and helped alert emergency crews of the movement of magma toward the surface. Luckily, the first vent to open at La Palma was in a sparsely populated area.

Observing an active volcano up close is best left for the satellites and the experts, Gonzalez-Santana said.

When she was just feet from the volcano, that same watch that alerted her of the eruption recorded Gonzalez-Santana’s elevated heart rate, peaking above 180 beats a minute as she pointed a thermal-imaging camera at the fire fountains in one of the central vents.

“That was probably the coolest and scariest moment of my whole trip,” Gonzalez-Santana said. “Seeing a volcano erupt is impressive. But the noise, the rumbling. It’s hard to put into words. It’s as if you feel the vibrations when you’re that close.”