NSFGEO-NERC: Latest Pleistocene-Holocene incremental slip record of the Kekerengu-Jordan fault system, northern South Island, New Zealand

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Mounting evidence suggests that the occurrence of large earthquakes on both single faults and more complex fault systems is not a random process. Increasing numbers of observations indicate earthquake clustering in time and space, with changes in the rates at which faults slip, and variations in the patterns of loading (which triggers earthquakes). Also seen are possibly coordinated waxing and waning of slip on mechanically complementary faults in regional fault systems, that is, one fault slipping for a period of time of up to several thousand years, but slip subsequently shifting to another nearby fault at a later time. Although a thorough understanding of both the causes and generality of these phenomena is of basic importance for fault mechanics, earthquake physics, and importantly, for more accurate assessments of seismic hazard, our ability to evaluate the importance of these behaviours has been severely limited by lack of available data. In particular, there are too few comprehensive observations of the timing of ancient earthquakes and measurements of changing fault slip rates over periods of many thousands of years to assess fully the collective behaviour of major plate-boundary fault systems in time and space. These major systems, which represent the locations where one tectonic plate slides past another one, are where many large and damaging earthquakes occur, and increasing our knowledge of how they work will significantly enhance our ability to forecast future earthquake probabilities, and to take steps to prepare for these events.Our international team, including scientists from the UK, USA and New Zealand, will reconstruct the slip history of part of the Marlborough Fault System in South Island, New Zealand, over the last 15,000 years, and build a detailed record of ancient earthquake events over this time. We shall focus our efforts on the Kekerengu-Jordan Thrust System; these faults moved in the very large (magnitude 7.8) Kaikoura earthquake of the 14th November 2016, allowing us to relate this recent event that was recorded in significant detail to past earthquakes.