Hydromechanical coupling in tectonic faults and the origin of aseismic slip, quasi-dynamic transients and earthquake rupture

Introduction

Earthquakes and tectonic fault slip are among the most hazardous and unpredictable natural phenomena. Fluids play a key role in tectonic faulting, and recent research suggests that fluids are central in both human-induced seismicity and the mode of fault slip, ranging from episodic tremor and slip to slow earthquakes.

Challenges in Research

However, the lack of accessibility to earthquake faults and the complexity of physical processes has limited our ability to develop holistic models for hydromechanical coupling in fault zones. Geophysical observations have the potential for illuminating precursors to failure for the spectrum of tectonic faulting; however, we lack key laboratory data to connect these observations with predictive, physics-based models.

Project Goals

The ambitious goal of HYQUAKE is to build a physically based framework to understand and predict fluid pressure induced fault slip for a range of fault motion, from aseismic creep to destructive earthquakes.

Interdisciplinary Approach

The HYQUAKE approach is interdisciplinary and at the frontier of laboratory earthquake physics, seismology, and data/computer science. The goal is to provide unprecedented quantitative constraints on the key physical processes that couple:

1. Fault friction
2. The dynamics of strain localization
3. Fluid flow controlling earthquakes and fault slip behavior

Research Program

Specifically, I will build a research program around unusually well-controlled rock deformation experiments tightly connected to numerical models of faulting.

Integration of Data

HYQUAKE will integrate lab data on fault zone elastic properties, frictional rheology, and hydromechanical parameters using state-of-the-art experimental equipment built within the project, along with machine learning to forecast labquake.

Imaging Techniques

Details of deformation processes, fluid flow, and fault failure will be imaged using novel acoustic techniques.

Future Implications

These data will set the stage for the upscaling of laboratory observations to the prediction of natural faulting by coupling physics-based machine learning with 3D hydro-mechanical models.