Plate-boundary faults are massive, complex structures that display a wide range of seismic and aseismic behavior, and understanding the physics that govern their activity requires a highly multidisciplinary approach. 

 

In this talk, I will use a combination of geodetic, geologic, and numerical results to show how the 3D structure of the Main Himalayan thrust controls its frictional behavior, and offer a new perspective on the interplay between earthquakes and long-term fault evolution.

Following the 2015 Nepal earthquake, I provided the first high-resolution, wide-swath synthetic aperture radar image of the resulting ground deformation to the geophysics community. These data reveal clearly where the fault slipped, and by integrating them with 3D structural models, we show that the earthquake was bounded on all sides by sharp bends or ramps along the fault.

Combining these results with long-term GPS observations of ground motion, I demonstrate how the fault structure controls both the long- and short-term behavior of the megathrust throughout the Himalaya, and in turn, how fault friction interacts to control the fault structure over time.

In the future, developing a better understanding of the interaction between the structure and behavior of faults will require input from a diverse set of geophysical techniques and disciplines. 

 

In addition to mapping ground deformation at high precision with synthetic aperture radar, I will show some promising new ground-based geodetic methods and physics-based numerical tools I have pioneered. Together with seismic and geologic observations, they will enable us to paint a more complete picture of how earthquakes interact with and control the faults they occur on.