My research profile spans three interlinked themes, underpinned with a common applied geophysics thread that aims to better understand the solid Earth through a holistic laboratory experiments and simulations:
Research theme 1: Rock Physics: This discipline describes the combination of controlled laboratory rock deformation experiments with measurements of geophysical and seismological properties. These experiments and methodologies allow fundamental studies of deep Earth processes to be made – which cannot be directly accessed – for comparison to routinely collected field data. Over the last 20 years I have applied these methods to, (i) develop a new understanding between fluid flow (permeability) anisotropy, elastic-wave anisotropy and 3D pore fabric anisotropy, (ii) better understand rock mass stability and fault friction, and (iii) understand how the 3D rock fabric influences seismic attenuation and other geophysical data.
Research theme 2: Volcanotectonics & Geohazards: I extended the methods above, for the first time, to investigate fluid-driven seismicity in the shallow crust with particular focus on passive (triggered) seismicity in active volcanoes. These earthquakes in volcanic settings (known as ‘Volcano-Tectonic’, ‘Hybrid’ and ‘Low Frequency’ harmonic events) are diagnostic of conditions under the volcano and frequently detected before unrest. A new understanding of their generation in terms of fluid pressure, speed, and volume is now allowing new models to be developed for this important geological hazard, and better understand the key role that fluids have on the stability of volcanic flanks.
Research theme 3: Fluid-induced fracture mechanics: Fluids moving within a sealed impermeable rock mass will ultimately lead to fracture and failure due to over-pressurisation. This is both a natural phenomenon (e.g. veining, diking), and exploited during intentional hydraulic fracture. My research has successfully developed novel new apparatus to safely simulate this process at elevated pressure and temperature. These important new experiments have deconstructed the links between the high-pressure rock mechanics, fracture tip stresses, and the generated fracture energy (seismicity). This has allowed my group to better understand the speed of fracture, and its resistance (or ‘fracture toughness’) with increasing simulated depth. This is a unique area of research providing valuable information impacting the design of deep geological resources (e.g. Geothermal energy) as well as preventing unwanted fracturing, reducing risk and hazard in heat-generating processes (e.g. deep geological storage of nuclear waste).
Specific areas of active research include:
- Dyke movement and arrest: how material properties affect the movement of magmas and dyke structures during magma transport.
- Mechanical properties of crystal-bearing magma: Seismogenic lavas and eruption forecasting using laboratory AE location analysis and pore fabric characterisation.
- Forecasting material failure and geological hazard via passive seismicity and attenuation.
- Coupled Processes: linking Thermal-Hydraulic-Mechanical interactions in the shallow crust to passive seismic signals; Seismic precursors to earthquakes (‘Volcano-Tectonic’ and ‘Low Frequency’ harmonic events).
- Porous Media & Anisotropy: Investigation of fluid flow (permeability) anisotropy from elastic-wave anisotropy and 3D pore fabric anisotropy.
To see my full up-to-date profile and research group activities and outputs, see: https://www.researchgate.net/profile/Philip_Benson2 and the RML Pure portal