Simulation of Tsunami Hazards Affecting the East Cape Region, New Zealand

The east coast of New Zealand is known for being exposed to a variety of tsunami sources, both those arising from the nearby Hikurangi subduction zone and its associated crustal faults, and those arising from more distant parts of the Pacific. Using numerical simulations with a parallelized computer model, we assess the tsunami inundation hazard posed to the most populated coastal communities on the east coast of the East Cape region, New Zealand, which had not been evaluated before. Our tsunami inundation hazard study is based on severe but realistic scenario events from a selection of local and distant earthquake tsunami sources. Such modelling covers a gap in knowledge caused by the short historical record of tsunamis in this region (covering <200 years), and the sparse observations of historical tsunamis due to a largely rural population. We identify that the worst flooding is often not associated with the first wave arrivals, and that coastal oscillations can last a long time in distant events. The modelling results allow us to determine typical characteristics of the pattern of flooding, specific to an area. This information is important for emergency planning and preparedness.