What do you do?
I use computer simulations to learn about the strength of rocks deep inside the Earth's mantle (the rock layer going down 2890 kilometers). Depending on what area of the mantle you're looking at, the rocks might be deforming by cracking or stretching or flowing like a fluid. The deformation mechanism (termed rheology) depends on the type of rocks, the temperature, the depth beneath surface and how quickly the rock is deformed. However, since we can not go hundreds of kilometers inside the Earth to observe and measure what is happening, I use computer simulations to test ideas about the strength of rocks and how the strength varies from place to place. By comparing the output from the computer simulations to several different kinds of observations made at the surface of the Earth, like topography, gravity and orientation of stress, and by using other information from laboratory experiments on deformation mechanisms, melting, and geochemistry, I aim to reconstruct the rheologic structure of the Earth's mantle.

Why should the general public be interested in what you do?
The past and present evolution of the Earth depends strongly on the physical properties of the rocks, not just at the Earth's surface but also deep inside the Earth. For example, the strength of rocks hundreds of kilometers below the surface can influence the occurrence of earthquakes near the surface. In places like Japan, Alaska, and South America, where one tectonic plate bends and sinks beneath another tectonic plate, the strength of rocks deep inside the mantle regulate how fast the plates can move past each other, which influences how much stress builds up between them, which in turn can affect the size and number of earthquakes occurring near the surface.

Why does it interest you?
I am fascinated by how motions taking place hundreds of kilometers deep within the Earth can lead to the great height of the Himalayas (6 km; 3.7 miles) or depth of the Mariana deep-sea trench (10 km; 6.2 miles), the folded and stretched layers of rocks in places like the Alps or the explosive eruptions of volcanoes like Mt. St. Helens. These places are dramatic visual evidence for what's going on inside the Earth; the game is to decipher how the interior of the Earth works from these bits of evidence spread all over the surface.

What major advances/discoveries have occurred in your research field over the last 10 years?
The major discoveries in my field over the past 10 years have been made by researchers able to use more sophisticated computer simulations to reproduce an increasingly complex set of observations. Some of this research has demonstrated the link between deep processes within the Earth and deformation at the surface, while others have made great progress in simulating plate tectonics by including more realistic physical parameters. Currently, a great deal of research is focused on bringing together geophysical and geochemical processes in numerical models to investigate how they interact with each other to create the complex style of deformation observed at the surface.