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A Repeating Earthquake Catalog from 2003 to 2018 for the Raukumara Peninsula, Northern Hikurangi Subduction Margin, New Zealand
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  • Laura Hughes,
  • Calum John Chamberlain,
  • John Townend,
  • Amanda M. Thomas
Laura Hughes
Victoria University of Wellington

Corresponding Author:[email protected]

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Calum John Chamberlain
Victoria University of Wellington
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John Townend
Victoria University of Wellington
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Amanda M. Thomas
University of Oregon
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Abstract

Repeating earthquakes provide a novel way of monitoring how stresses load faults between large earthquakes. To date, however, and despite the availability of long-duration, high-quality seismological datasets, little attention has been paid to tectonic repeating earthquakes in New Zealand. We develop a workflow and composite criterion for identifying repeating earthquakes in New Zealand, using data from the GeoNet permanent seismic network, and present New Zealand’s first decadal-scale repeating earthquake catalog. For events to be identified as repeating in this study, two or more events must have a normalized cross-correlation of at least 0.95 at two or more seismic stations, when calculated for 75% of the earthquake coda. By applying our composite criterion to seismicity around the Raukumara Peninsula, northern Hikurangi subduction margin, we have identified 62 repeating earthquake families occurring between 2003 and 2018, consisting of 160 individual earthquakes. These families have a magnitude range of MW 1.5-4.5 and recurrence intervals of < 1-12 years. The repeating earthquake families identified in this study coincide with the location and timing of previously identified slow-slip events and tremor. However, the responses shown to slow-slip are not consistent within families or within regional groups.