Geology and Geological Engineering

Dr. Tim Masterlark
Geodynamics: Exploring Earth with Numerical Models
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Dr. Tim Masterlark

Ph.D. (2000), University of Wisconsin
Associate Professor and
Mickelson Professorship
Geology and Geological Engineering
South Dakota School of Mines
Rapid City, SD 57701
phone 605-394-5326

Research synopsis

As residents of a dynamic planet, we face an array of geohazards from volcanic eruptions, earthquakes, and tsunamis. From a physical standpoint, fluid-solid coupling drives these dynamic systems. Fluid magma propagates in dikes through the solid rock of an active volcano to either remain in storage at depth or erupt at the land surface. The coseismic shift of the solid seafloor from a megathrust earthquake excites the overlying ocean, resulting in tsunami waves. These fluid waves, in turn, interact with the solid coastal areas with devastating consequences. Large earthquakes transfer stress to the near-field region surrounding the rupture. Diffusive flow of pore fluids in the crust and viscous flow of the mantle slowly relax these stresses, producing delayed aftershocks.

The physical processes of fluid-solid coupling are naturally extended to processes associated with energy production. Hydrofracking involves the propagation of fluid-filled fractures that unlock hydrocarbons from unconventional reservoirs. The waste ("fracking") fluids may be disposed of via injection into deep reservoirs. This injection perturbs the ambient stress and fluid pressure that may trigger seismsicity. Likewise, the same physical principle of propagating fluid-filled fractures is useful for improving the efficiency of geothermal systems.

We specialize in using Abaqus-based Finite Element Models (FEMs) to simulate fluid-solid coupling that drives deformation systems of earthquakes and active volcanoes, as well as human-induced fracture propagation and induced seismicity. We are particularly focused on developing methods to embed FEMs in nonlinear inverse analyses that use observations of Earth's surface deformation and seismicity to characterize inaccessible deformation sources at depth. The Geodynamics Laboratory is equipped with Heavy Workstations (multi-core CPUs, TFLOP GPU acceleration, Big RAM, and Solid-state drives) that are specifically designed for FEM-based analyses. Example targets include:

  • NSF Geophysics (2013-2016)
    FEM-based inverse methods to estimate nonlinear geometric source parameters of volcano deformation from geodetic data. Study sites are Okmok volcano, Alaska, and Tunguraha, Ecuador.

  • NSF Geophysics (2009-2014)
    Unraveling coseismic and postseismic deformation: A prerequisite for analyses of stress-coupling and tsunami genesis. Study sites include the 2011 M9 Tohoku Earthquake and 2004 M9 Sumatra-Andaman Earthquake.

  • NASA ROSES ESI (2012-2016)
    Near-field postseismic poroelastic deformation, InSAR observations, and modeling. Multiple study sites. Collaborative research with NASA JPL.

  • JAXA 4th ALOS Research Announcement for ALOS-2 (2013-2017)
    Interferometric analysis of JERS-1, ALOS, and ALOS-2 SAR data for Okmok Volcano to constrain dynamic models of magmatic processes.
FEMs of mega-earthquakes: Viscoelastic relaxation translates to postseismic deformation and stress.

FEM of Tungurahua Volcano: This model simulates deformation caused by a pressurized dike embedded in the complex domain of an active volcano.

Abaqus XFEM: Propagation of a fluid-filled fracture in a 2D domain.
contact: Dept. of Geology and Geological Engineering, 501 E. Saint Joseph St., SDSMT, Rapid City, SD 57701
phone: (605)394-5326 / fax: (605)394-6703 / email: timothy.masterlark@sdsmt.edu