Modeling tsunammi inundation for hazard assessment of the Coral Coast of Fiji: Communities of Sigatoka and Cuvu

A tsunami hazard assessment was conducted for the communities of Sigatoka and Cuvu, located on the island of Viti Levu, Fiji. The study presents an overview of historical seismic and tsunami impact on the Pacific Island nation of Fiji in order to identify source areas of relevance to the study. In addition, the sensitivity of the Coral Coast of Viti Levu to tsunamis coming from different parts of the New Hebrides and Tonga-Kermadec Subduction zones was investigated and used to select worst case tsunami scenarios. Following the methodology developed at the NOAA Center for Tsunami Research (Tang et al, 2006) more than 40 tsunami simulations were conducted on a low-resolution model. Four of the sources simulated were selected as the most hazardous to the area of interest and were subsequently modeled on a high-resolution (10 meter) grid of Sigatoka and Cuvu. To these sources, an ensemble of 20 additional sources in the Tonga-Kermadec Subduction Zone were selected for evaluation. These sources were identified in an Intergovernmental Oceanographic Commission (IOC) report (IOC Working Report No. 289, 2018) by a group of seismic experts on tsunami sources in the region. Finally, one source from a 2022 study conducted by NCTR for the US Department of State to assess tsunami hazard to the city of Suva, Fiji using a probabilistic approach was selected for simulation on the high-resolution model. The non-linear shallow water wave inundation Method Of Splitting Tsunami (MOST) model (Titov and Gonz\'alez, 1997) is one of the tsunami modeling codes in use by the National Tsunami Hazard Mitigation Program (NTHMP, 2011), (NTHMP, 2017) of the US to conduct tsunami inundation studies with the purpose of developing evacuations maps. The MOST code was used in this study to determine tsunami maximum amplitude, arrival and duration times, flow depths, tsunami inundation, current speeds and attenuation.
Comment: Study for IOC Tsunami Ready Project. 39 Pages