About the Lab

What we are working on

The research topics can be broadly divided into three domains.

High pressure and high temperature rock deformation

The laboratory is equipped with a wide range of facilities, which can reproduce pressure, temperature and strain conditions relevant to the Earth’s crust and upper mantle. Experiments performed at high pressures (up to 3 GPa) and temperatures (up to 1500 K) allow us to quantify the mechanical properties and microphysical evolution of rocks deforming by viscous and frictional mechanisms. Some examples of ongoing or upcoming projects include:

• Subduction interface mechanics from shallow to deep
• Strain localisation and grain growth in the mantle 
  

Large-scale mechanical testing under controlled environmental conditions

Long-term damage evolution in natural rock slopes or underground excavations is governed by the growth and coalescence of fractures through intact rock. In order to gain greater insight into landslide activity, erosion, and the long-term performance of man-made underground structures, we study the behavior of rock under conditions typical of those that regulate the temporal nature of fracture growth and rock mass strength degradation, and in particular the conditions in near-surface environments where degradation is controlled by changes in:

• mechanical loading (e.g. through deglaciation), or,
• climate (e.g. increasing temperatures or water availability),
• and, the degradation of infrastructure as a result of:
• ongoing mechanical stress changes, or,
• variations in temperature, available water, or water chemistry.

Laboratory seismology

Fault reactivation related to frictional breakdown is not well understood and is further complicated by subsurface complexities relating to thermo-hydro-mechanical-chemical (THMC) behavior that governs aspects of the stress evolution in the near-fault field. Understanding this behavior has large implications on our ability to safely extract subsurface resources related to enhanced geothermal systems (EGS). We study the effect of temperature, fluids and material heterogeneity on bulk aspects of frictional breakdown and rock deformation, which appears to be linked to the presence of localised seismicity even in a laboratory setting.

While the study of acoustic emission in the lab has been around for decades, traditional techniques neglect key methodologies that have recently allowed for the extraction of important source information carried within different phases of the incoming seismic waves. Using absolutely-calibrated broadband piezoelectric transducers (PZT) capable of operating in hot and pressurised environments, we look at how seismicity (-S) interacts with the coupled mechanisms of a THMC-S framework.

Using these experiments, we can investigate downscaled seismicity and its relationship to bulk frictional weakening behavior in a controlled manner. The interpretation of scale dependence of earthquake source parameters should rely on the adoption of a physical description of the governing processes at both the micro- and macroscopic scales investigated here.