| Julien Chaput, doctoral candidate in geophysics, sends holiday greetings from Antarctica.
“It's always an honor to have your research acknowledged by the scientific community,” Chaput said. “Quite a bit of work and head scratching went into it, and if you can get a consensual nod out of your peers when the dust settles, then it's always a lovely thing.”
During the 2007-08 research expedition, New Mexico Tech geoscientists and IRIS PASSCAL staff deployed an array of 140 broadband seismometers around Mount Erebus, one of the only continuously active volcanoes on the planet. Chaput employed new techniques of reducing the resulting data, which maximize the signal-to-noise ratio of faint echoes from within the volcano. Chaput’s new imaging techniques allow scientists to create 3-D models of the interior of the volcano and track its changes over time.
“What we've managed to do is the first step in many, but it's a first successful implementation of a seismic imaging method which is particularly well suited to volcanoes and other highly complex structures,” he said. “This may prove to be one of the first seismic methods capable of real-time imaging the interior of active volcanoes.”
Chaput is working in an area where the theoretical pioneers don't really know the practical limitations or feasible implementations of their theories, he said.
“Julien is an example of a guy who is really pushing the methodology of examining the interior of the Earth in new directions,” Aster said. “With IRIS PASSCAL, we can put out lots of sensors. When you have enough, you can disentangle all the tiny echoes of what’s coming back from the hidden structures. Julien’s job is to take those signals, disentangle the complicated echoes and figure out where the molten rock is in the volcano.”
Aster said the application of Chaput’s work goes beyond imaging volcanoes and could eventually be applied to other geologic formations, including oil fields, mining and other industries.
Chaput said his results are essentially what many people have thought might be theoretically possible using the evolving techniques of seismic interferometry, but had been infeasible due to the inherent limitations related to instrumentation and data-reduction tools. The Mt. Erebus Volcano and its permanent lava lake continuously produce seismic signals. The array of 140 seismic stations collected seismic signals from each eruption. Chaput then combines those seismic signals from the dense seismograph array to interpret the scattered wavefields. Chaput and his colleagues developed a whole new system for how to interpret and make use of what they were seeing.
“The most exciting part is that it doesn't require artificial sources (such as dynamite), so we could in theory deploy an array of stations and recover an image of the volcano every time any seismic signal, such as an interior earthquake happens,” he said. “That would allow for high resolution structural monitoring of active volcanoes as they change. That particular point is a bit of a holy grail.”
Aster said Chaput is dedicated researcher who throws himself into his projects.
“Julien is a guy who works all night when he gets excited,” Aster said. “He’s a pleasure to work with because he’s always looking for the next opportunity to innovate and improve what he’s doing … and that’s how science advances.”
A native of Canada, Chaput earned his bachelor’s in New Brunswick and his master’s degree at the University of British Columbia in Vancouver. Since coming to New Mexico Tech in 2007, he’s spent three austral summers – that’s winter in the northern hemisphere – in Antarctica, working for one season at the Erebus and two seasons at Byrd Camp, working on the Polar Earth Observing Network, or POLENET program, an international project with Aster that uses the latest instruments and new data-reducing tools to study the seismology and geology of the polar regions.
Chaput said Mt. Erebus and Tech’s observatory there provide a pristine research environment and adventure opportunity.
“You get to snowmobile around in a completely alien landscape with jagged spires of rock and deep ice caves, some of which are much like saunas,” Chaput said. “You're also offered a truly unique window into the heart of the Earth through Erebus' open convecting lava lake. It's a thing of wonder. I had a few ‘snowmobile hero‘ moments as well.”
Chaput said that he’s learned a tremendous amount since coming to Tech. He said Aster, his advisor, has provided him with incredible datasets, conference opportunities, and tools of the trade on which he will build after completing his doctorate.
“I have nothing but good impressions when it comes to the level of research and innovation done in the Earth and Environmental Science Department,” he said. “We really do get to work on neat projects, and I hope to continue in that spirit wherever I go afterwards.”
Chaput was one of eight students tapped to receive the award at the Seismological Society Association meeting, which was announced in August.
This is the second year in a row that a Tech student has won the award. Dr. Jonathan McCarthy won in 2010, shortly before completing his Ph.D. in geophysics.
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By Thomas Guengerich/New Mexico Tech