Dr. Aagje Eijsink,

Aagje in front of a geothermal pool in New Zealand

Advised by Dr. Derek Elsworth

I moved to State College about a year ago, in May 2022 to join the Penn State Rock Mechanics Lab, after finishing my PhD degree at the Marum – Center for Marine Environmental Science in Bremen. I have always been interested in earthquakes even though they are not exactly common in the Netherlands, where I come from. I started doing laboratory rock friction experiments during my Bachelor degree at Utrecht University. For my Master thesis, I briefly ventured into the outdoors by studying rocks from a Precambrian subduction zone, but I decided that I prefer to study rocks in controlled laboratory experiments. Although it is not possible to see the rock during experiments, it is possible to control many of the variables, and measure what is going on inside the deformation device. The controlled environment that enables us to figure out exactly what is going on inside rock during the deformation process and sometimes earthquakes, is why I like this part of science so much.

There are many different types of rock friction experiments, but in general, we apply stress conditions that are representative for a specific setting inside the earths’ crust and then move one side of the laboratory ‘fault’ relative to the other. That way, we can study how the applied forces behave during sliding, specifically the frictional behavior of the fault. In my past work, I have studied a range of variables and how they influence friction and sliding stability, including fault surface roughness, host rock stiffness, lithology and interlayer water of clay minerals. The project that I work on at Penn State is about geothermal energy, and is focused mostly on the response of faults to increased temperatures and the permeability of faults during sliding. Geothermal energy is a great source of sustainable energy, but understanding the risks of induced seismicity and maintaining high levels of permeability to sustain enough flow of water to the surface to generate electricity are key components that have to be understood better before it can be widely adopted as a source for electricity.

Agje with the Nittany Lion in the All Sports Museum and setting up all sensors for an experiment in the pressure vessel.

Outside of research, which was the main reason to come to Penn State, I really enjoy living in State College, but especially the area around here. Although I enjoy spending time in nature in general, one of my favorite things to do in my free time is swimming, preferably in natural lakes, of which there are plenty around.