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This site is maintained by the MARGINS Office. Please share your comments and suggestions with us.
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Browse MARGINS
Awards in reverse chronological order after start
date (most recent first):
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What Locks Subduction Thrusts?
| MARGINS Focus Area |
Seismogenic
Zone |
| NSF Org |
OCE |
| Latest Amendment Date |
March 5, 2002 |
| Award Number |
0203664 |
| Award Instrument |
Standard Grant |
| Program Manager |
Rodey Batiza
OCE DIVISION OF OCEAN SCIENCES
GEO DIRECTORATE FOR GEOSCIENCES |
| Start Date |
April 1, 2002 |
| Expires |
March 31, 2005 (Estimated) |
| Expected Total Amount |
$179,148 (Estimated) |
| Investigator |
J. Casey Moore (Principal
Investigator current) |
| Sponsor |
U of Cal Santa Cruz
1156 High Street
Santa Cruz, CA 950641077 408/429-0111 |
| NSF Program |
1620 MARINE GEOLOGY AND GEOPHYSICS |
| Field Application |
0204000 Oceanography |
| Abstract |
Under this award, the PI will examine a well-documented Eocene-
Paleocene rock complex from a paleo subduction thrust, now exposed
in Alaska, in order to quantify and understand the differences,
at a variety of length scales, between the upper aseismic parts
of a subduction trust and the lower seismogenic parts. This study
will test the hypothesis that deposition of minerals in cracks strengthens
and locks subduction thrusts in the periods between major eatthquakes.
During field work, the PI and a PhD student will document changes
in structural fabric and mineral veins of various generations. Later
lab studies will look at changes in physical properties, and mineralogy
under similar PT conditions as presently exist in the SW Japan subduction
zone. Quantification of shear zone paramenters, changes in mineralogy,
intensity of pressure solution, density and porosity, and size/shape
of blocks and matrix, will allow interpretations of the importance
of simple sliding (aseismic) vs. stick-slip (seismic) behavior.
Further, the results of the lab experiments can be used to interpret
textures and structural features indicative of sliding, stick-slip,
and heating. These observations and measurements, including fluid
inclusion studies with Vrolijk, will be useful for testing ideas
about velocity weakening in actural subduction zones, providing
guidance for experimentalists on what types of materials are best
for deformation studies, a preview of what will be seen in riser
drilling at Nankai, and 10-100m scale constraints on interpreting
3D seismic studies in subduction complexes.
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