Seismogenic zone processes of Hikurangi subduction, New Zealand: illumination using the SAHKE seismic project

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Great earthquakes and tsunamis occur at subduction zones such as Sumatra, Japan, Peru-Chile, and Cascadia. The first three localities have been sites of recent events, while the third is expected to produce a great earthquake along the northwest coast of the U.S. at some time in the furture. The Hikurangi subduction system off North Island, New Zealand exhibits a range of slip conditions, from aseismic to strongly coupled, with strain release by coseismic, slow slip, and repeating microseismic events, but it has not been the site of a great M8+ earthquake, either because conditions here do not support such an event, or, more likely, because no large event has occurred since Europeans arrived there in the mid 19th century. Consequently, understanding seismicity in the Hikurangi subduction system is a matter of considerable societal relevance. Multi-disciplinary studies reveal the complex interplay between upper and lower plate structure, subducting sediment, thermal effects, regional tectonic stress regime, and fluid pressures to control the presence and distribution of the Hikurangi seismogenic zones. This study comprises a comprehensive seismological study of the southern Hikurangi system with the aim of characterizing its strongly coupled seismogenic zone and its downdip transition into an aseismic slow slip regime. In additional to its obvious societal relvance, the broader impacts of this study include cross-natioanl trianig of graduate students from the U.S., New Zealand and Japan, and a research experience for undergraduates.