|
Abstract
Seismic Coupling Along the New Hebrides Trench
James Edward Lundy, M.S.Geo.Sci.
The University of Texas at Austin, 1998
Supervisor: Stephen Grand
Nearly one hundred years of seismicity in the region of the New
Hebrides Trench and the Vanuatu Archipelago in the South West Pacific were analyzed to
determine what portion of slip along the trench axis is seismic. The New Hebrides Trench
is a region of active subduction and one known to have some anomalous geodetically
determined horizontal motion rates when compared with far-field regional convergence
vectors and predictions of modern global plate motion models. Analysis of averaged annual
seismic slip in events related to subduction indicate that only 10 to 30% of the plate
convergence is manifested as seismic slip along the majority of the trench axis despite
large bathymetric features currently impinging the central portion of the arc. This
suggests that although these large features are the likely cause of deformation within the
overriding plate, they do not lead to significantly stronger coupling at the plate
interface.
|