Grant: Discovery Grants Program - Individual

My research focuses on geophysical investigations of subduction zone structure and processes in relation to earthquake and tsunami hazards. The overarching objective of the proposed research program is to elucidate the role of geological structures in shaping the dynamics of the Hikurangi subduction zone in Aotearoa New Zealand (ANZ). This program leverages new international collaboration and offshore deployments of ocean-bottom seismographs with ANZ researchers. Combined with land-based seismographs, these seafloor stations remove the observational bias in the locked zone of Hikurangi that will host the next giant earthquake and cause damage in Wellington, the capital city of ANZ. All land and marine data are used to image and probe various components of the subduction zone structure and processes. We will investigate the role of geology and structure in the spatial distribution of frictional coupling between the two tectonic plates via seismic imaging. We will develop and combine innovative methods to produce 3D seismic wave speed models of the subduction zone and yield geological and structural information. These models will elucidate the detailed morphology and extent of the subduction zone fault and the role of upper vs. lower plate structure in controlling the distribution of fluids and fault locking. We will also examine temporal variations in the seismic wave speed structure associated with large stress and hydrologic perturbations that cause or result from fault rupture. For this, we will leverage new developments in data processing to probe the source of wave speed transients at high resolution throughout the crust. We will focus on changes associated with deep slow slips and sites surrounding the rupture zone of the 2016 magnitude 7.8 Kaikoura earthquake in ANZ. Elucidating the deep transients is crucial for modelling the stress field near the subduction zone fault and improving earthquake forecasts. Finally, we will dramatically augment and improve the earthquake catalogue in southern Hikurangi to examine the spatiotemporal patterns of seismicity in the locked zone. We will develop and apply deep learning models that consider broadband ocean-bottom seismic observations to reduce bias. This catalogue will serve to investigate the distribution of stress and active faulting in the locked zone, and changes in the stress field following the Kaikoura earthquake. The proposed research program is a key, practical approach to investigating important physical processes that govern the generation of large earthquakes at subduction zones. Funded personnel will contribute to the marine deployments in ANZ and receive high-level training in seismology, computing and data analysis, preparing them for a broad range of opportunities in academia, public or private industry. Importantly, this program is firmly grounded in the principles of open science to ensure that the outcomes of this work (publications, data, and software) are accessible to all.