Dr David Dempsey
PhD, MSc, BSc (Hons)
David joined the Engineering Science Department in 2015. Prior to that, he worked on renewable energy and natural hazard problems at Los Alamos National Laboratory and Stanford University. David completed his PhD at the University of Auckland in 2012, studying the relationship between faults and geothermal systems in the central North Island.
Research | Current
My research passion is computational geoscience. In particular, I like to use computer models to address practical challenges in renewable energy and natural hazards.
- What do human-triggered earthquakes and subtle electromagnetic signals tell us about conditions several kilometres below ground?
- How do interaction between geothermal systems and deep, underground magma bodies a control volcanic eruption or the formation of a gold deposit?
- What are computer models able (and unable!) to tell us about the nature and likelihood of future earthquakes?
To address these questions, my research group designs models of the fundamental physics of Earth systems, written in thousands of lines of computer code (preferably Python!) We use all sorts of data to calibrate these models, and a range of mathematical techniques to understand the uncertainty in their predictions.
Teaching | Current
I like to use Jupyter Notebooks in teaching my courses (see my library of Azure notebooks to the right).
ENGSCI 233: Computational Techniques and Computer Systems
Computational treatment of data, combinatorial algorithms, error, integration and interpolation, numerical solutions to ODEs, parallelisation, performance and quality control of algorithms.
ENGSCI 263: Engineering Science Design I
Introduction to concepts of modelling of engineering problems, including model formulation, dimensional analysis, solution procedures, comparisons with reality, and shortcomings, with examples from elementary mechanics, structures, hydrostatics, one-dimensional heat, diffusion and fluid motion.
ENGSCI 343: Mathematical and Computational Modelling in Mechanics
Vector calculus and integral theorems. Continuum hypothesis, indicial notation, deformation, strain, traction, stress, principal directions, tensors, invariants, constitutive laws, isotropy, homogeneity. Navier-Stokes and Navier's equations. Isotropic elasticity, elastic moduli, plane stress and plane strain. Airy stress function, Viscous flow, simple solutions of the Navier-Stokes equations. Flow over flat plates, boundary layers. Ideal flow, velocity potential, stream function, 2-D flows.
ENGSCI 741: Waves and Fracture
Advanced topics in mechanics including: waves and wave motion with applications to acoustics, optics, fluid flow problems and shock discontinuities using numerical methods. Fracture: modes of, displacement discontinuity in linear elasticity, stress intensity factor, spectral solution methods, finite friction. Applications include: hydraulic fracturing, earthquakes, macroscale strength of materials.
Jeremy Riffault - "A mixed stochastic/deterministic model for induced seismicity applied to the 2011 Paralana EGS stimulation"
Irene Wallis - "Conceptual Models of Permeability in High-Temperature, volcanic hosted geothermal systems: An Interdisciplinary Approach to Facing Data and Uncertainty"
Alberto Ardid - "Joint inversion of temperatures in a geothermal field using MT, clay alteration models, and geothermal reservoir simulation"
Alexander Catalinac - "Human-triggered earthquakes: a hybrid laboratory-computational study"
Martin Letourneur - "Reservoir simulation of interacting magma and geothermal systems."
Areas of expertise
Earthquake modelling; reservoir geomechanics; subsurface fluid modelling; induced seismicity; geothermal reservoir modelling; CO2 sequestration; geological heterogeneity; coupled magmatic-hydrothermal systems.
Selected publications and creative works (Research Outputs)
- Dempsey, D., & Riffault, J. (2019). Response of Induced Seismicity to Injection Rate Reduction: Models of Delay, Decay, Quiescence, Recovery, and Oklahoma. WATER RESOURCES RESEARCH, 55 (1), 656-681. 10.1029/2018WR023587
- Dempsey, D., & Suckale, J. (2017). Physics-based forecasting of induced seismicity at Groningen gas field, the Netherlands. Geophysical Research Letters, 44 (15), 7773-7782. 10.1002/2017GL073878
- Dempsey, D., & Suckale, J. (2016). Collective properties of injection-induced earthquake sequences: 1. Model description and directivity bias. Journal of Geophysical Research: Solid Earth, 121 (5), 3609-3637. 10.1002/2015JB012550
- Dempsey, D., Suckale, J., & Huang, Y. (2016). Collective properties of injection-induced earthquake sequences: 2. Spatiotemporal evolution and magnitude frequency distributions. Journal of Geophysical Research: Solid Earth, 121 (5), 3638-3665. 10.1002/2015JB012551
- Birdsell, D. T., Rajaram, H., Dempsey, D., & Viswanathan, H. S. (2015). Hydraulic fracturing fluid migration in the subsurface: A review and expanded modeling results. Water Resources Research, 51 (9), 7159-7188. 10.1002/2015WR017810
- Dempsey, D., Kelkar, S., Davatzes, N., Hickman, S., & Moos, D. (2015). Numerical modeling of injection, stress and permeability enhancement during shear stimulation at the Desert Peak Enhanced Geothermal System. International Journal of Rock Mechanics and Mining Sciences, 78, 190-206. 10.1016/j.ijrmms.2015.06.003
- Dempsey, D., O'Malley D, & Pawar, R. (2015). Reducing uncertainty associated with CO2 injection and brine production in heterogeneous formations. International Journal of Greenhouse Gas Control, 37, 24-37. 10.1016/j.ijggc.2015.03.004
- Dempsey, D., Kelkar, S., & Pawar, R. (2014). Passive injection: A strategy for mitigating reservoir pressurization, induced seismicity and brine migration in geologic CO₂ storage. International Journal of Greenhouse Gas Control, 28, 96-113. 10.1016/j.ijggc.2014.06.002