The effect of fault-bend folding on seismic velocity in the marginal ridge of accretionary prisms
Pure and Applied Geophysics PAGEOPH
By: Y. Cai, Chun-Yong Wang, W.-t. Hwang, and G.R. Cochrane
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Abstract
Fluid venting in accretionary prisms, which feeds chemosynthetic biological communities, occurs mostly on the marginal thrust ridge. New seismic data for the marginal ridge of the Cascadia prism show significantly lower velocity than that in the adjacent oceanic basin and place important constraints on the interpretations of why fluid venting occurs mostly on the marginal ridge. We employed a finite-element method to analyze a typical fault-bend folding model to explain the phenomenon. The fault in the model is simulated by contact elements. The elements are characterized not only by finite sliding along a slide line, but also by elastoplastic deformation. We present the results of a stress analysis which show that the marginal ridge is under subhorizontal extension and the frontal thrust is under compression. This state of stress favors the growth of tensile cracks in the marginal ridge, facilitates fluid flow and reduces seismic velocities therein; on the other hand, it may close fluid pathways along the frontal thrust and divert fluid flow to the marginal ridge. ?? 1995 Birkha??user Verlag.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | The effect of fault-bend folding on seismic velocity in the marginal ridge of accretionary prisms |
| Series title | Pure and Applied Geophysics PAGEOPH |
| DOI | 10.1007/BF00879593 |
| Volume | 145 |
| Issue | 3-4 |
| Year Published | 1995 |
| Language | English |
| Publisher location | Birkha??user-Verlag |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Pure and Applied Geophysics PAGEOPH |
| First page | 637 |
| Last page | 646 |
| Google Analytic Metrics | Metrics page |