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Title: Observations of wave-induced pore pressure gradients and bed level response on a surf zone sandbar: WAVE-INDUCED PORE PRESSURE GRADIENTS
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
DOI PREFIX: 10.1029
Date Published:
Journal Name:
Journal of Geophysical Research: Oceans
Page Range / eLocation ID:
5169 to 5193
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Abstract

    Inversions of InSAR ground deformation in the Delaware Basin have revealed an aseismic slip on semi‐optimally oriented normal faults located close to disposal wells. The slip, occurring over 3–5 years, extends approximately 1 km down‐dip, over 10 km along strike, and reaches 25 cm. We develop and calibrate 2D and pseudo‐3D coupled pore pressure diffusion and rate‐state models with velocity‐strengthening friction tailored to this unique height‐bounded fault geometry. Pressure diffusion is limited to a high‐permeability fault damage zone, and the net influx of fluid is adjusted to match the observed slip. A 1–2 MPa pressure increase initiates slip, with ∼5 MPa additional pressure increase required to produce ∼20 cm slip. Most slip occurs at approximately constant friction. Fault zone permeability must exceed ∼10−13 m2to match the along‐strike extent of slip. Models of the type developed here can be used to operationally manage injection‐induced aseismic slip.

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