Satellites emit radar waves, which reflect off the Earth’s surface and return to the satellite. By analyzing differences in how long it takes for the waves to complete that trip over time, researchers can detect slight changes in elevation resulting from ground deformation.
“These radar satellites are at about 460 miles high, yet the accuracy for deformation measurements is about 1 centimeter,” Wauthier said. “It’s amazing how precise this is. What’s even more fascinating is that the spatial coverage of radar data is much better than if you use GPS stations and can create ground deformation maps.”
Utilizing the Advanced CyberInfrastructure (ICS-ACI) high-performance computing system, Wauthier is able to remotely study volcanic activity and surface deformation through the use of large datasets of radar satellite images. Her type of work is fundamental for the understanding of volcanic activity and volcanic subsystems.
“An erupting volcano is very intense. It is an amazing experience once you get close to the lava, feel how hot it is and know that it is coming from the Earth,” Wauthier said.
One of Wauthier’s current projects is to study the Kilauea Volcano in Hawaii. She is combining seismic and InSAR data to better model the subsurface sources. Wauthier is attempting to numerically model the interactions between the magma intrusions and earthquakes on the southern flank of the active volcano. This work would help understand the Kilauea volcano better and potentially explain volcanic unrest like the current crisis.
When studying volcanoes, Wauthier said it is important to understand the different ways that volcanoes can form, because each formation has specific behaviors. There are subduction settings, when two tectonic plates collide; continental rifting, when two tectonic plates are splitting or diverging; and hot-spot volcanism, when a volcano is in the middle of a tectonic plate.
By using InSAR, Wauthier is able to infer the layout of the magma plumbing system. Much like a building’s plumbing system, which transports water, the magma plumbing system is a network of underground tunnels and channels through which magma travels. Whether or not this magma reaches the surface to be erupted as lava is what Wauthier is trying to model and forecast.
When doing her research, there are sometimes areas that are hard to reach or dangerous to visit. InSAR gives insight on information that would otherwise be nearly impossible to obtain.
“For example, some dangerous volcanoes can’t be easily studied because they aren’t instrumented on the ground with GPS stations,” Wauthier said. “Remote sensing may be the only information you have.”
During her doctoral work in Belgium from 2007-2011, Wauthier worked on modeling the 2002 eruption of the Nyiragongo volcano, which caused hundreds of causalities in Goma, Democratic Republic of Congo.
Wauthier inferred two hypotheses to explain the InSAR deformation: It was either caused by shifting of a tectonic fault or a magma intrusion, meaning that magma came up through the layers of the Earth but cooled before reaching the surface.
Wauthier found geological deformation maps from the Kivu area stored in the Royal Museum for Central Africa in Belgium which favored the tectonic explanation.
In 2010, Wauthier was able to conduct field work by visiting the Democratic Republic of Congo to help the Goma Volcano Observatory with the Nyamulagira volcano’s ongoing 2010 eruption. The Nyamulagira volcano is roughly 8 miles northwest of Nyiragongo. During field work in the Goma area, Wauthier found ancient exposed eruptive fissures.
“The old geological map said that the structure was a fault, which would have favored my tectonic explanation,” Wauthier said. “When I was inspecting it on the field it turned out to be an old eruptive fissure. This meant that the best explanation was my hypothesis of a magma intrusion.”
Wauthier’s time spent in the Democratic Republic of Congo showed that discoveries can be made outside of field work. If it were not for her computational modeling, it would have been significantly harder to infer her two hypotheses.
This type of research requires time and computer processing power. Wauthier said that her co-appointment at ICS allows her to take advantage of ICS-ACI and big computing capabilities.
“It’s a lot of data. You have many images taken over one area and that allows you to create deformation maps, which will show you an amount of deformation over a period of time,” Wauthier said. “Using these images, you can try to simulate what is going on underground.”
Wauthier attempts to reproduce those observed deformation maps by using complex algorithms that simulate active subsurface sources like magma chambers, intrusions or slip on faults that may be responsible for the deformation.
Her ultimate goal is to use her computational models to forecast when, where and how a volcano may erupt.
“I want to understand volcanoes better and help the people living around them in order to limit any possible casualties,” Wauthier said.