Multimode surface waveform tomography of the Pacific Ocean: a closer look at the lithospheric cooling signature

Maggi, A. and Debayle, E. and Priestley, K. F. and Barruol, G. (2006) Multimode surface waveform tomography of the Pacific Ocean: a closer look at the lithospheric cooling signature. Geophysical Journal International, 166 (3). pp. 1384-1397. DOI https://doi.org/10.1111/j.1365-246X.2006.03037.x

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Abstract

We present a regional surface waveform tomography of the Pacific upper mantle, obtained using an automated multimode surface waveform inversion technique on fundamental and higher mode Rayleigh waves, to constrain the VSV structure down to ∼400 km depth. We have improved on previous implementations of this technique by robustly accounting for the effects of uncertainties in earthquake source parameters in the tomographic inversion. We have furthermore improved path coverage in the South Pacific region by including Rayleigh wave observations from the French Polynesian Pacific Lithosphere and Upper Mantle Experiment deployment. This improvement has led to imaging of vertical low-velocity structures associated with hotspots within the South Pacific Super-Swell region. We have produced an age-dependent average cross-section for the Pacific Ocean lithosphere and found that the increase in VSV with age is broadly compatible with a half-space cooling model of oceanic lithosphere formation. We cannot confirm evidence for a Pacific-wide reheating event. Our synthetic tests show that detailed interpretation of average VSV trends across the Pacific Ocean may be misleading unless lateral resolution and amplitude recovery are uniform across the region, a condition that is difficult to achieve in such a large oceanic basin with current seismic stations.

Item Type:	Article
Uncontrolled Keywords:	2006 AREP IA52 2006 P
Subjects:	02 - Geodynamics, Geophysics and Tectonics
Divisions:	02 - Geodynamics, Geophysics and Tectonics
Journal or Publication Title:	Geophysical Journal International
Volume:	166
Page Range:	pp. 1384-1397
Identification Number:	https://doi.org/10.1111/j.1365-246X.2006.03037.x
Depositing User:	Sarah Humbert
Date Deposited:	16 Feb 2009 13:03
Last Modified:	23 Jul 2013 10:07
URI:	http://eprints.esc.cam.ac.uk/id/eprint/504

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