Anisotropy and deformation in the Earth's mantle : seismological observations, geodynamical models, and laboratory experiments

In this thesis I report the results of several studies of elastic anisotropy and deformation in the Earth's mantle, using shear wave splitting measurements, numerical models of geodynamical processes, and laboratory experiments on mantle minerals. I evaluate the performance of several methods for measuring shear wave splitting at broadband stations, and discuss how different measurements can inform our interpretation of mantle anisotropy. I describe a set of shear wave splitting measurements from both teleseismic and local earthquakes at 65 stations of the F-net array in Japan. I find considerable evidence from the measured splitting patterns for complex and heterogeneous anisotropy beneath Japan associated with the subduction of the Pacific and Philippine Sea plates beneath Eurasia. The comparison of teleseismic and local splitting at stations in southwestern Japan provides strong evidence for trench-parallel anisotropy in the mantle wedge above the subducting slab. I consider several scenarios that would produce the observed anisotropy and conclude that the most likely model for deformation beneath the Ryukyu arc is corner flow in the mantle wedge, with a region extending ~ 150 kilometers from the trench dominated by B-type olivine fabric.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Long, Maureen Devaney

Advisor dc:contributor.advisor

• Robert D. Van der Hilst.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/37360

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/37360