Slow slip source characterized by lithological and geometric heterogeneity
Barnes, Philip M.; Wallace, Laura M.; Saffer, Demian M.; Bell, Rebecca E.; Underwood, Michael B.; Fagereng, Ake; Meneghini, Francesca; Savage, Heather M.; Rabinowitz, Hannah S.; Morgan, Julia K.; Kitajima, Hiroko; Kutterolf, Steffen; Hashimoto, Yoshitaka; Engelmann de Oliveira, Christie H.; Noda, Atsushi; Crundwell, Martin P.; Shepherd, Claire L.; Woodhouse, Adam D.; Harris, Robert N.; Wang, Maomao; Henrys, Stuart; Barker, Daniel H. N.; Petronotis, Katerina E.; Bourlange, Sylvain M.; Clennell, Michael B.; Cook, Ann E.; Dugan, Brandon E.; Elger, Judith; Fulton, Patrick M.; Gamboa, Davide; Greve, Annika; Han, Shuoshuo; Huepers, Andre; Ikari, Matt J.; Ito, Yoshihiro; Kim, Gil Young; Koge, Hiroaki; Lee, Hikweon; Li, Xuesen; Luo, Min; Malie, Pierre R.; Moore, Gregory F.; Mountjoy, Joshu J.; McNamara, David D.; Paganoni, Matteo; Screaton, Elizabeth J.; Shankar, Uma; Shreedharan, Srisharan; Solomon, Evan A.; Wang, Xiujuan
(2020) Science advances, volume 6, issue 13
(Article)
Abstract
Slow slip events (SSEs) accommodate a significant proportion of tectonic plate motion at subduction zones, yet little is known about the faults that actually host them. The shallow depth (<2 km) of well-documented SSEs at the Hikurangi subduction zone offshore New Zealand offers a unique opportunity to link geophysical imaging
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of the subduction zone with direct access to incoming material that represents the megathrust fault rocks hosting slow slip. Two recent International Ocean Discovery Program Expeditions sampled this incoming material before it is entrained immediately down-dip along the shallow plate interface. Drilling results, tied to regional seismic reflection images, reveal heterogeneous lithologies with highly variable physical properties entering the SSE source region. These observations suggest that SSEs and associated slow earthquake phenomena are promoted by lithological, mechanical, and frictional heterogeneity within the fault zone, enhanced by geometric complexity associated with subduction of rough crust.
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ISSN: 2375-2548
Publisher: American Association for the Advancement of Science
(Peer reviewed)
