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Crustal structure and apparent tectonic underplating from receiver function analysis in South Island, New Zealand

Spasojević, Sonja and Clayton, Robert W. (2008) Crustal structure and apparent tectonic underplating from receiver function analysis in South Island, New Zealand. Journal of Geophysical Research B, 113 (B4). Art. No. B04307. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20121001-091317326

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Abstract

We utilize seismic converted phases on more than 700 receiver functions calculated for 42 stations in the South Island, New Zealand, to infer crustal and uppermost mantle structure. We determine the crustal thickness from direct observations of conversion from the Moho interface and infer zone of the maximum thickness being located along the axis of the Southern Alps, just east from the Alpine fault. The crustal root widens from north to south in the direction perpendicular to the Alpine fault and appears to have an asymmetric structure. Stations in the alpine portion of island show evidence for prominent midcrustal conversions. Significant crustal thickening is developed in response to both the convergent component of the motion on the Alpine fault and subduction in the Fiordland region. We propose two models for a strong uppermost mantle conversion that occurs at depths between 33 and 83 km on 16 stations and forms a large continuous feature along the east coast and in the central portions of the South Island. Our preferred model attributes upper mantle conversion to tectonically underplated oceanic crust formed by late Oligocene-Miocene spreading between the Australian and Pacific plates, which was detached from the Australian plate and tectonically underplated under the South Island. An alternative model attributes the upper mantle conversions to long-lived seismic fabric created by subduction of the Gondwanaland margin.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2007JB005166 DOIUNSPECIFIED
http://www.agu.org/pubs/crossref/2008/2007JB005166.shtmlPublisherUNSPECIFIED
ORCID:
AuthorORCID
Clayton, Robert W.0000-0003-3323-3508
Additional Information:© 2008 by the American Geophysical Union. Received 11 May 2007; revised 3 October 2007; accepted 24 November 2007; published 24 April 2008. We want to acknowledge New Zealand GeoNet project and its sponsors EQC, GNS Science, and FRST for providing data from NZNSN; Monica Kohler for providing the SAPSE data; David Okaya for providing three-component SIGHT data; Joann Stock for providing plate reconstruction data and useful discussion about the tectonics of New Zealand; and Zhimei Yan for help with processing of receiver function data. This paper has benefited from discussions with Fred Davey, Brian Davies, and Bruce Luyendyk and comments from two anonymous reviewers.
Group:Seismological Laboratory
Subject Keywords:crustal structure; tectonic underplating; receiver functions
Issue or Number:B4
Record Number:CaltechAUTHORS:20121001-091317326
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20121001-091317326
Official Citation:Spasojevic, S., and R. W. Clayton (2008), Crustal structure and apparent tectonic underplating from receiver function analysis in South Island, New Zealand, J. Geophys. Res., 113, B04307, doi:10.1029/2007JB005166
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34575
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:01 Oct 2012 21:09
Last Modified:03 Oct 2019 04:20

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