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The geologic record of deep episodic tremor and slip

Nicholas W. Hayman and Luc L. Lavier
The geologic record of deep episodic tremor and slip
Geology (Boulder) (January 2014) 42 (3): 195-198


Transient and episodic slow slip accommodates a great deal of tectonic strain and may be mechanically linked with locked regions of seismically hazardous faults. Best documented in subduction zones and associated with nonvolcanic tremor, most proposed mechanisms for slow slip revolve around the transition between stable and unstable frictional sliding. The dilemma is that slow slip is generated at a wide range of crustal depths, including at pressure-temperature conditions where frictional deformation mechanisms give way to predominantly viscous ones. We present a model for how fracture and viscous flow within mid-crustal shear zones can produce episodic creep transients. Our model for such transients stems from geological examples of shear zones that formed at temperatures and pressures of >500 degrees C and >0.6 GPa during early orogenesis, following Late Cretaceous subduction of a backarc ocean basin. Within these shear zones, relatively strong lenses of metabasalt localized fluid-filled fractures that were subsequently deformed by viscous flow in surrounding quartzofeldspathic gneiss. The spatial and temporal characteristics of the modeled creep events are similar to those of slow-slip events observed in modern subduction zones. We therefore suggest that some episodic tremor and slip can originate through combined fracture and viscous flow across shear zones comprising mixtures of strong and weak materials.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 42
Serial Issue: 3
Title: The geologic record of deep episodic tremor and slip
Affiliation: University of Texas at Austin, Institute for Geophysics, Austin, TX, United States
Pages: 195-198
Published: 20140110
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 26
Accession Number: 2014-009749
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2014058
Illustration Description: illus. incl. geol. sketch map
S54°52'60" - S54°52'60", W68°10'00" - W68°10'00"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201407
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