A left-lateral strike-slip fault seaward of the Oregon convergent margin
Article Abstract:
The Wecoma fault in the Cascadia Basin is a left- lateral strike-slip fault lying west of the Oregon convergent margin. Recently mapped using the SeaMARC I and Seabeam sonar, it is 18.5 km long and extends 293 degrees northwest from the base of the continental slope, at an angle of 45degrees, 10 minutes north. Extending 3.5 km into the sedimentary section, the fault intersects seafloor formations that show left-lateral separations of 120-2500 m, implying an average slip-rate of 5-12 mm/yr since 10-24 ka. Fault movement began at an estimated 210 ka and activity during the Holocene was indicated.
Publication Name: Tectonics
Subject: Earth sciences
ISSN: 0278-7407
Year: 1992
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Development of the accretionary prism along Peru and material flux after subduction of Nazca Ridge
Article Abstract:
The Nazca Ridge accretionary prism along Peru grew rapidly after the ridge crest subducted. Material flux showed great variation as the margin initially eroded and then grew by accretion. A large prism taper allowed rapid accretion and around 60% of the trench was accreted. The taper became narrower as the rates of accretion got reduced. This coincided with an increase in trench sediment, and sediment subduction allowed thickened sediment section input. The subduction of the Nazca Ridge changed the volume of material brought into the subduction zone.
Publication Name: Tectonics
Subject: Earth sciences
ISSN: 0278-7407
Year: 1996
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Structural variation and landward vergence at the toe of the Oregon accretionary prism
Article Abstract:
A study of the Oregon accretionary prism shows that landward vergence occurs due to low basal shear stress, an arcward dipping decollement, and to some extent a relatively strong wedge. Backward verging thrust plates can move preferentially only when these three factors are combined to create the landward vergence. Changes in pore pressure conditions in the Cascadia Basin sediments may have caused hanges in the structural style.
Publication Name: Tectonics
Subject: Earth sciences
ISSN: 0278-7407
Year: 1995
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