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Illuminating a contorted slab with a complex intraslab rupture evolution during the 2021 Mw 7.3 East Cape, New Zealand earthquake

Title: Illuminating a contorted slab with a complex intraslab rupture evolution during the 2021 Mw 7.3 East Cape, New Zealand earthquake
Authors: Okuwaki, R
Hicks, SP
Craig, TJ
Fan, W
Goes, S
Wright, TJ
Yagi, Y
Item Type: Journal Article
Abstract: The state-of-stress within subducting oceanic plates controls rupture processes of deep intraslab earthquakes. However, little is known about how the large-scale plate geometry and the stress regime relate to the physical nature of the deep intraslab earthquakes. Here we find, by using globally and locally observed seismic records, that the moment magnitude 7.3 2021 East Cape, New Zealand earthquake was driven by a combination of shallow trench-normal extension and unexpectedly, deep trench-parallel compression. We find multiple rupture episodes comprising a mixture of reverse, strike-slip, and normal faulting. Reverse faulting due to the trench-parallel compression is unexpected given the apparent subduction direction, so we require a differential buoyancy-driven stress rotation, which contorts the slab near the edge of the Hikurangi plateau. Our finding highlights that buoyant features in subducting plates may cause diverse rupture behavior of intraslab earthquakes due to the resulting heterogeneous stress state within slabs.
Issue Date: 28-Dec-2021
Date of Acceptance: 10-Dec-2021
URI: http://hdl.handle.net/10044/1/93538
DOI: 10.1029/2021gl095117
ISSN: 0094-8276
Publisher: American Geophysical Union (AGU)
Start Page: 1
End Page: 13
Journal / Book Title: Geophysical Research Letters
Volume: 48
Issue: 24
Copyright Statement: © 2021. American Geophysical Union. All Rights Reserved. This is the accepted version of the following article: Okuwaki, R., Hicks, S. P., Craig, T. J., Fan, W., Goes, S., Wright, T. J., & Yagi, Y. (2021). Illuminating a contorted slab with a complex intraslab rupture evolution during the 2021 Mw 7.3 East Cape, New Zealand earthquake. Geophysical Research Letters, 48, e2021GL095117., which has been published in final form at https://doi.org/10.1029/2021GL095117
Keywords: Meteorology & Atmospheric Sciences
Publication Status: Published
Online Publication Date: 2021-12-21
Appears in Collections:Earth Science and Engineering