Subduction zones

Subduction zones are the sites of giant earthquakes and associated tsunamis, caused by an oceanic plate rubbing against a continental margin along a megathrust fault as it makes its way down into the Earth’s mantle. Newly discovered phenomena of episodic slow earthquakes at subduction zones have revolutionized our understanding of the earthquake cycle at the transition between seismic and aseismic deformation. Relating their occurrence and physics to the complex geological environment of subduction zones remains one of the most important seismological grand challenges. My group investigates the structural properties of various subduction zones worldwide using seismic data. Our results make important contributions to understanding the driving mechanisms of subduction zone slow earthquakes by identifying the role of water in the mechanical stability of megathrust faults.

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Pascal Audet
Associate Professor of Geophysics & University Research Chair

Publications

Automatic detection and location of seismic events from time-delay projection mapping and neural network classification

The past several decades have seen an exponential increase in the volume of available seismic data, and with it has come the need to …

Uncovering the physical controls of deep subduction zone slow slip using supervised classification of subducting plate features

Deep slow slip events (SSEs) at subduction zones have significantly contributed to refining our understanding of the megathrust …

Seismic evidence for megathrust fault-valve behavior during episodic tremor and slip

Fault slip behavior during episodic tremor and slow slip (ETS) events, which occur at the deep extension of subduction zone megathrust …

Fluid pressure and shear zone development over the locked to slow slip region in Cascadia

At subduction zones, the deep seismogenic transition from a frictionally locked to steady sliding interface is thought to primarily …

Teleseismic constraints on the geological environment of deep episodic slow earthquakes in subduction zone forearcs: A review

More than a decade after the discovery of deep episodic slow slip and tremor, or slow earthquakes, at subduction zones, much research …

Low‐frequency earthquakes at the southern Cascadia margin

We use seismic waveform data from the Mendocino Experiment to detect low‐frequency earthquakes (LFEs) beneath Northern California …

Phase‐Weighted Stacking Applied to Low‐Frequency Earthquakes

We apply phase‐weighted stacking (PWS) to the analysis of low‐frequency earthquakes (LFEs) in the Parkfield, California, region and …

Seismic evidence for rotating mantle flow around subducting slab edge associated with oceanic microplate capture

Tectonic plate reorganization at a subduction zone edge is a fundamental process that controls oceanic plate fragmentation and capture. …

Possible control of subduction zone slow-earthquake periodicity by silica enrichment

Seismic and geodetic observations in subduction zone forearcs indicate that slow earthquakes, including episodic tremor and slip, recur …

Hydrologic control of forearc strength and seismicity in the Costa Rican subduction zone

Subduction zones can exhibit variable seismic behaviour, ranging from great earthquakes to slow slip. This variability may be linked to …

High pore pressures and porosity at 35 km depth in the Cascadia subduction zone

In the Cascadia subduction zone, beneath southern Vancouver Island at 25–45 km depth, converted teleseismic waves reveal an ∼5-km-thick …

Slab morphology in the Cascadia fore arc and its relation to episodic tremor and slip

Episodic tremor and slip (ETS) events in subduction zones occur in the general vicinity of the plate boundary, downdip of the locked …

Seismic evidence for overpressured subducted oceanic crust and megathrust fault sealing

Water and hydrous minerals play a key part in geodynamic processes at subduction zones by weakening the plate boundary, aiding slip and …

Morphology of the Explorer–Juan de Fuca slab edge in northern Cascadia: Imaging plate capture at a ridge-trench-transform triple junction

The Explorer plate is a young oceanic microplate that accommodates relative motion between the Pacific, Juan de Fuca, and North America …