Magnetotelluric imaging of fluid processes at the subduction interface of the Hikurangi margin, New Zealand

The subduction interface beneath the northern part of the Hikurangi subduction margin on the east coast of New Zealand's North Island is exceptionally shallow and cool compared with other margins where slow slip has been observed. Here we use magnetotelluric data to show that a marked decrease...

Full description

Saved in:
Bibliographic Details
Published in:Geophysical research letters 2012-02, Vol.39 (4), p.n/a
Main Authors: Heise, Wiebke, Caldwell, T. Grant, Hill, Graham J., Bennie, Stewart L., Wallin, Erin, Bertrand, Edward A.
Format: Article
Language:English
Subjects:
Earth sciences
Earth, ocean, space
Electromagnetics
Exact sciences and technology
magnetotellurics
New Zealand
Plate tectonics
slow slip
subduction
underplating
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The subduction interface beneath the northern part of the Hikurangi subduction margin on the east coast of New Zealand's North Island is exceptionally shallow and cool compared with other margins where slow slip has been observed. Here we use magnetotelluric data to show that a marked decrease in the conductivity of the fore‐arc sediments coincides with the onset of seismicity at ∼10 km depth. Below the sediments, a dipping band of seismicity and intermediate conductivity at the subduction interface connects to a deeper more conductive zone above the down‐going plate. This deeper conductive zone is interpreted to be under‐plated sediments. These results and results from previous seismic tomography in the area suggest that the intermediate resistivity zone represents a region of upward fluid transport near the plate interface followed by fluid escape into the upper‐plate. Key Points Magnetotellutic data was inverted using a 3D modelling algorithm The model shows sedimentary underplating and a region of upward fluid escape
ISSN:0094-8276
1944-8007
DOI:10.1029/2011GL050150