Evidence of seismic slip on a large splay fault in the Hikurangi subduction zone

Coffey, G. L., Savage, H. M., Polissar, P. J., Meneghini, Francesca, Ikari, Matt J., Fagereng, Åke ORCID: https://orcid.org/0000-0001-6335-8534, Morgan, Julia K. and Wang, Maomao 2021. Evidence of seismic slip on a large splay fault in the Hikurangi subduction zone. Geochemistry, Geophysics, Geosystems 22 (8) , e2021GC009638. 10.1029/2021GC009638

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Abstract

The Hikurangi subduction zone is capable of producing moderate to large earthquakes as well as regularly repeating slow slip events. However, it is unclear what structures host these different slip styles along the margin. Here we address whether splay faults can host seismic slip at shallow (<1 km) depth by investigating the Pāpaku fault, sampled during International Ocean Discovery Program Expedition 375. We use biomarker thermal maturity to search for evidence of frictional heating within turbiditic sediments of the Pāpaku fault. Four zones of localized high temperature are found near the top of the fault zone, which are interpreted to be zones of localized seismic slip. Thermal modeling shows that the most likely maximum displacement on the shallow Pāpaku fault during each event was 14–17 m. Our results demonstrate that the Pāpaku fault, and potentially other splay faults along the margin, host coseismic slip and have the potential to produce large tsunami (e.g., runup heights of >1 m as observed in the 1947 Poverty and Tolaga Bay earthquakes.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	American Geophysical Union
ISSN:	1525-2027
Date of First Compliant Deposit:	15 September 2021
Date of Acceptance:	14 April 2021
Last Modified:	07 May 2023 19:59
URI:	https://orca.cardiff.ac.uk/id/eprint/144156

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