Software provides researchers with more accurate view of Earth’s interior
Recent reports out of Northwestern University that vast amounts of water are not only in the oceans and topmost layers of the solid Earth but also stored deep within the Earth’s mantle hundreds of kilometers down may have rocked mainstream media and the general public to the core, but the announcement didn’t come as news to Texas A&M University researcher Wolfgang Bangerth.
“I think the people in the field knew this for a long time,” said Bangerth, a professor in the Texas A&M Department of Mathematicssince 2005 and an expert in computational science and mathematical modeling. “It’s not really a surprise result. The novelty lies in the fact that someone could experimentally show it.”
Such revealing results are made possible by people like Bangerth, a broad-based scientist with proficiency in both mathematics and geophysics who teamed with former Texas A&M colleague Timo Heister a few years ago to write a software program called ASPECT (Advanced Solver for Problems in Earth’s ConvecTion). Their code — the evolving result of a five-year, $800,000 subcontract that runs through 2015 with the National Science Foundation-funded Computational Infrastructure for Geodynamics in California — is used by geodynamics researchers around the world who are working to develop a clearer picture of the Earth’s interior and to accurately describe how material flows in the Earth’s mantle with the help of computerized simulation and mathematical modeling.
Bangerth cites one such international researcher — Juliane Dannberg, a graduate student at the German Research Center for Geosciences in Potsdam, Germany — who is using the ASPECT code to model what happens when hot material is transported from the Earth’s core-mantle boundary upward into the surrounding colder regions. Normally, the enormous pressures inside Earth prevent material from melting, but chemical impurities in the rock — for instance, the presence of small amounts of water — can lead to partial melting that radically alters the rock’s properties.
Dannberg’s resulting video (shown at top) shows this process, called thermochemical convection, with each frame representing activity during a 500,000-year period to simulate a total of 275 million years of inner-Earth history.