A Novel Method to Determine Probabilistic Tsunami Hazard Using a Physics-Based Synthetic Earthquake Catalog: A New Zealand Case Study

Tsunamis can have devastating consequences for coastal communities. Yet hazards from future tsunamis are difficult to quantify due to their rarity in the instrumental record. Statistical earthquake catalogs have previously been used to quantify tsunami hazards. For the first time, we use a physics-based synthetic earthquake catalog to assess probabilistic tsunami hazard in a local region. We analyze a 30,000-year catalog to capture a wide range of the source complexity evident in tsunamigenic earthquakes. We produce models of land-surface displacements and subsequent tsunamis from 2,585 earthquakes with magnitude > M-W 7.0. Modeled slip of the Hikurangi and Tonga-Kermadec subduction thrusts generated maximum wave heights at the coast of up to 28 m and these earthquakes pose the greatest tsunami hazard along New Zealand's coastline. The results provide a "proof of concept" for using earthquake simulators for probabilistic tsunami hazard models. They further present a platform upon which next-generation probabilistic tsunami inundation models may be constructed.