Hydrogeological modeling of porous flow in the Oregon accretionary prism

Journal Article · Sat Apr 01 04:00:00 EST 1989 · Geology; (USA)

DOI:https://doi.org/10.1130/0091-7613(1989)017<0321:HMOPFI>2.3.CO;2· OSTI ID:7254066

Hwang, Win-tsuang ^[1]; von Huene, R ^[2]

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1. Univ. of California, Berkeley (USA)
2. Geological Survey, Menlo Park, CA (USA)

Venting of pore fluid was recently reported near the front of the Oregon accretionary prism and was directly measured at one of the venting sites during Alvin dives. In this study, the authors model the flow of pore fluid in the Oregon accretionaly prism. They use seismic reflection sections to constrain subsurface structures, drill-hole results from Deep Sea Drilling Project Leg 18 to constrain sediment properties, and regional tectonic information to constrain the timing and the rate of plate convergence and sediment imbrication and thickening. The results of two-dimensional, time-element, finite-element modeling show that high pore pressures are generated beneath the decollement due to the load of imbricated and thickened sediments. Diffusive flow at a rate of several millimetres per year is predicted within the accretionary prism if fault zone permeability is discounted. The presence of a decollement or permeable fault penetrating the accretionary prism, as imaged on the seismic reflection section, can drastically alter the patterns of fluid flow and produce focused venting of fluid, as observed. On the other hand, fluid venting along faults may not significantly alter the high pore pressures below the decollement.

• OSTI ID: 7254066
• Journal Information: Geology; (USA), Journal Name: Geology; (USA) Vol. 17:4; ISSN GLGYB; ISSN 0091-7613
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
DRILLING
FEDERAL REGION X
FINITE ELEMENT METHOD
FLOW MODELS
FLUIDS
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
HYDROLOGY
MATHEMATICAL MODELS
NORTH AMERICA
NUMERICAL SOLUTION
OFFSHORE SITES
OREGON
PERMEABILITY
PLATE TECTONICS
PORE PRESSURE
RESERVOIR FLUIDS
SEDIMENTATION
SEISMIC SURVEYS
SURVEYS
TECTONICS
TIME DEPENDENCE
TWO-DIMENSIONAL CALCULATIONS
USA