Subducting plate fault structure and its implications for sediment subduction /
| Main Author: | |
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1989.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The morpho-structural pattern common to outer trench slopes is examined in detail and its relationship with sediment subduction is critically evaluated. Compilations of bathymetric, seismic reflection, and supporting geophysical and geological data are interpreted to produce circum-Pacific structural features maps. Mapping documents the distribution of fault structures and permits quantification of surface void space. Fractures and normal faults initiate as the direct result of oriented plate bending stresses, independent of the relative motion direction. The shape of the overriding plate appears to be the dominant influence on the geometry of bending. Frequency distributions of fault length and displacement are approximated by exponential or power-law functions. Maximum fault displacement decreases with distance from the trench. A positive correlation exists between average fault displacement and fault length. Geometric considerations demonstrate that surface fractures probably do not penetrate below Moho. The observed fault length-frequency and length-displacement distributions are consistent with studies of fracture propagation which predict that the crack extension force increases linearly as a function of crack length. This results in a distribution skewed toward large numbers of short, shallow penetrating fractures and faults. Statistical comparison of means for graben width indicates that graben width does not increase within 50 km of the trench. Because fault displacement does increase, this suggests that fault orientations favor increased vertical displacement over horizontal extension. Outer trench slope faulting is commonly manifest as graben and half-graben, into which sediments are passively or actively emplaced and subducted. A circum-Pacific comparison indicates that sediment volume is significantly in excess of void volume. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Oceanography." |
| Physical Description: | xi, 191 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |