Assessing Occurrence Patterns of Shallow Hikurangi Slow Slip Events Using Renewal Processes

Abstract

We investigate the occurrence patterns of SSEs along the shallow (<15 km) portion of the Hikurangi subduction zone. First, we build a manual catalog constraining timing and length of 92 SSEs between 2006 and 2024. Then, we investigate SSE occurrence patterns by fitting a renewal process, using Bayesian inference to obtain the posterior distribution of model parameters. Our results show that SSE recurrence intervals vary along the Hikurangi margin; less frequent SSEs occur in the southern part of the margin. The periodicity of SSEs also changes along strike. SSEs in the northern part of the margin occur more regularly than those at the central part. Finally, we do not find conclusive evidence that 2016 Mw 7.8 Kaikōura earthquake had a lasting effect on SSE occurrence patterns.