Research

 

Subduction Zone Structure

I study seismic attributes of the subducting oceanic Juan de Fuca plate beneath the forearc crust in the Cascadia subduction zone to map the morphology of the descending slab and to place constraints on the structural controls associated with megathrust (M~9) earhquakes and episodic tremor and slip events. Results indicate evidence for elevated pore-fluid pressure (>hydrostatic pressure) within the subducted oceanic crust, which have important implications for the permeability of the plate interface and the transport of water in subduction zones. I also use seismic data to locate the termination of subduction and associated slab edge tectonism at the northern end of Cascadia beneath Vancouver Island.

Seismology

I develop seismological tools to improve the characterization of subsurface structure in both spatial and temporal dimensions. For example, I propose novel applications of the teleseismic receiver function method to study scattering from vertical faults and the temporal evolution of crustal velocity structure following earthquakes in California. I also use a wide-angle elastic one-way wave equation to model waveform distortions due to 3D propagation and scattering of teleseismic body-waves travelling through realistic 2D heterogeneous, anisotropic Earth models.

Publications:


Audet and Okaya, 2011. Seismic imaging of the San Andreas fault in northern California using receiver functions


Audet, 2010. Temporal variations in crustal scattering structure near Parkfield, California, using receiver functions


Audet et al., 2007. Teleseismic waveform modelling with a one-way wave equation

Lithospheric rheology

I study the variations and the anisotropy of the effective elastic thickness of continental lithosphere from the spectral relations between Bouguer gravity and topography and using equations for the flexure of an effective elastic plate. I use and develop different spectral methods to improve upon the spatio-spectral and azimuthal resolution of the coherence. I relate the variations in elastic thickness and mechanical anisotropy to the rheology and to geophysical indicators of deformation to build a conceptual model of lithospheric deformation that has implications for our understanding of continental evolution and the supercontinent cycle.

Planetary science

I develop and use a wavelet technique on the sphere to study gravity and topography of the terrestrial planets in the inner solar system (Earth, Venus, Mars and the Moon). I develop models of elastic shell flexure to estimate the thickness and thermal structure of the lithosphere. These estimates are useful to constrain the formation and evolution of the outermost rigid layer of the planet and to place constraints on heat loss from the planets’ interior.

Publications:


Audet and Johnson, 2011. Lithospheric and thermal structure of the Moon from gravity and topography.


Audet, 2011. Directional wavelet analysis on the sphere: Application to gravity and topography of the terrestrial planets.