Maximilian J. Werner


The stress field in the Earth’s crust is constantly evolving. Plate tectonic motion slowly accumulates strain energy in the lithosphere over time scales of hundreds and thousands of years. To accommodate the movement of near-rigid plates along their fragmented boundaries, frictional slip occurs on geological faults over a surprising range of temporal and spatial scales. Seismic waves, carrying their own dynamic stress field, are excited by fast ruptures that range in size from millimeters to thousands of kilometers in the crust. In contrast, slowly propagating slip events, which also play an important role in accommodating plate motion, reveal themselves by the quasi-static deformation of the Earth’s surface and sometimes by seismic ruptures triggered by the passing creep fronts.

But slip events are not simply witnesses to the local strength of faults, they are also perpetrators of change. Because, although the average shear stress is decreased on ruptured patches, the reconfigured stress field can locally increase the chances of future slip. Geometric and kinematic incompatibilities during the rupture of a heterogeneous crust cause irregular stress concentrations that may lead to earthquakes and other mechanisms of stress release. Static and dynamic elastic deformation, post-seismic afterslip, viscous relaxation, poro-elastic rebound, pore-fluid flow, stress corrosion, static fatigue and probably other mechanisms of stress transfer are likely to play a role in the constantly evolving stress field of the crust. Further complicating the picture, these stresses can be transferred over large distances in this near-elastic medium. 

It is my goal to understand and quantify the intertwined evolution of the crust’s stress field with the occurrence and propagation of seismic and aseismic slip. Because knowledge of the complete stress tensor at all locations will be impossible to obtain, we need to understand the physical principles and mechanisms for how the crust self-organizes. I study the constraints on this organization from the occurrence of earthquakes and aseismic slip by physical modeling of earthquakes that I confront with seismic data. In my approach to studying the interaction of the crust, the fault networks and earthquakes, I am inspired by the success of statistical mechanics to derive macroscopic equations from a statistical description of the microscopic mechanics.

As I strive to discover new insights into earthquake science, I believe that as seismologists we carry a responsibility for preparing society for earthquake-related disasters. I therefore actively participate in the evaluation of untested assumptions in seismic hazard assessments and apply my knowledge of earthquake processes towards better hazard estimates. While we cannot predict earthquakes, we can employ validated models of dynamically evolving hazard to estimate future earthquake potential.

About my research

photos: Guyot Hall, Princeton University.

Lecturer, School of Earth Sciences, University of Bristol

Visiting Associate Research Scholar, Department of Geosciences, Princeton University

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