Skip to Main Content
Book Chapter

The Pacific megagash: A future plate boundary?

By
Jean-Paul Montagner
Jean-Paul Montagner
Laboratoire de Sismologie, UMR7154, Institut de Physique du Globe, 1 rue Jussieu, 75238 Paris cedex 05, France
Search for other works by this author on:
Don L. Anderson
Don L. Anderson
Seismological Laboratory, California Institute of Technology, MS 252-21, Pasadena, California 91125, USA
Search for other works by this author on:
Published:
October 01, 2015

Seismic anisotropy is an efficient way to investigate the deformation field within the upper mantle. In the framework of rigid tectonic plates, we make use of recent tomographic models of azimuthal anisotropy to derive the best rotation pole of the Pacific plate in the uppermost 200 km of the mantle. It is found to be in good agreement with current plate motion (NUVEL1, HS3, and NNR). However, when dividing the Pacific plate into two subplates separated by what we refer to as the megagash, an east-west low-velocity and low-anisotropy band extending across the Pacific plate from Samoa-Tonga to the Easter–Juan Fernández Islands, the rotation pole of northern Pacific is still in agreement with current plate motion but not the rotation pole of the southern part of the Pacific, far away from the “classical” rotation pole of the Pacific plate. This result suggests a differential motion between the North and South Pacific and an ongoing reorganization of plates in the Pacific Ocean. The megagash might be a future plate boundary between the North and South Pacific plates, associated with the intense volcanism along this band.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Special Papers

The Interdisciplinary Earth: A Volume in Honor of Don L. Anderson

Gillian R. Foulger
Gillian R. Foulger
Department of Earth Sciences, Durham University, Durham DH1 3LE, UK
Search for other works by this author on:
Michele Lustrino
Michele Lustrino
Dipartimento di Scienze della Terra, Universita` degli Studi di Roma La Sapienza, P.le A. Moro, 5, 00185 Roma, Italy
Search for other works by this author on:
Scott D. King
Scott D. King
Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061, USA
Search for other works by this author on:
Geological Society of America
Volume
514
ISBN print:
9780813725147
Publication date:
October 01, 2015

References

Related

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal