Understanding slow slip event mechanisms and seismic hazard using local earthquakes: insights from the northern Hikurangi margin, Aotearoa New Zealand

This project forms part of the NZ3D-FWI experiment, which aims to characterise the margin architecture of the northern Hikurangi margin, Aotearoa New Zealand. The northern Hikurangi margin experiences slow slip events every 6-24 months, likely associated with the subduction of seamounts and fluid-rich topography that contributes to heterogeneous fluid and stress distributions. We use seismological methods to characterise the source region of these slow slip events, and investigate their links with local earthquakes. We first create a catalogue of local earthquakes between December 2017 and October 2018, analysing spatiotemporal variation in seismicity in relation to two small slow slip events. We then use the catalogue for local earthquake tomography, to characterise subsurface variations in wavespeeds. We then use seismic anisotropy methods to characterise subsurface fluid distributions and temporal variations in fluid content.