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Structure of the subduction system in southern Peru from seismic array data

Phillips, Kristin and Clayton, Robert W. and Davis, Paul and Tavera, Hernando and Guy, Richard and Skinner, Steven and Stubailo, Igor and Audin, Laurence and Aguilar, Victor (2012) Structure of the subduction system in southern Peru from seismic array data. Journal of Geophysical Research B, 117 (B11). Art. No. B11306. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20130115-145644857

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Abstract

The subduction zone in southern Peru is imaged using converted phases from teleseismic P, PP, and PKP waves and Pwave tomography using local and teleseismic events with a linear array of 50 broadband seismic stations spanning 300 km from the coast to near Lake Titicaca. The slab dips at 30° and can be observed to a depth of over 200 km. The Moho is seen as a continuous interface along the profile, and the crustal thickness in the back-arc region (the Altiplano) is 75 km thick, which is sufficient to isostatically support the Andes, as evidenced by the gravity. The shallow crust has zones of negative impedance at a depth of 20 km, which is likely the result of volcanism. At the midcrustal level of 40 km, there is a continuous structure with a positive impedance contrast, which we interpret as the western extent of the Brazilian Craton as it underthrusts to the west. V_p/V_s ratios estimated from receiver function stacks show average values for this region with a few areas of elevated V_p/V_s near the volcanic arc and at a few points in the Altiplano. The results support a model of crustal thickening in which the margin crust is underthrust by the Brazilian Shield.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2012JB009540DOIUNSPECIFIED
http://onlinelibrary.wiley.com/doi/10.1029/2012JB009540/abstractPublisherUNSPECIFIED
ORCID:
AuthorORCID
Clayton, Robert W.0000-0003-3323-3508
Additional Information:© 2012 American Geophysical Union. Received 18 June 2012; revised 3 October 2012; accepted 14 October 2012; published 28 November 2012. We thank the Betty and Gordon Moore Foundation for their support through the Tectonics Observatory at Caltech. This research was partially support by NSF award EAR-1045683. This is contribution number 199 from the Tectonics Observatory at Caltech.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
Betty and Gordon Moore FoundationUNSPECIFIED
NSFEAR-1045683
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory199
Record Number:CaltechAUTHORS:20130115-145644857
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20130115-145644857
Official Citation:Phillips, K., R. W. Clayton, P. Davis, H. Tavera, R. Guy, S. Skinner, I. Stubailo, L. Audin, and V. Aguilar (2012), Structure of the subduction system in southern Peru from seismic array data, J. Geophys. Res., 117, B11306, doi:10.1029/2012JB009540.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36403
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:15 Jan 2013 23:44
Last Modified:31 Jan 2017 20:48

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