Estimating tidal inundation in the aftermath of the 2018 Palu earthquake

Disasters broadly impact livelihood and the environment. Interrelated disasters cause significant casualties and loss because each type of disaster contributes to a series of impacts. An example of multiple disaster events in Indonesia is the 2018 Palu earthquake. This earthquake triggered tsunami, liquefaction, and rupture. Many studies on this earthquake only focused on either earthquake, tsunami, or liquefaction without conducting further impact analysis of a combined hazard. This study aimed to estimate tidal inundation in Palu City based on the deformation rate related to the earthquake and sea level rise. Synthetic Aperture Radar (SAR) data were processed with Parallel Small Baseline Subset Interferometry (P-SBAS) to produce a deformation rate using the Geohazard Exploitation Platform (GEP). This rate was then combined with DEMNAS data and modelled sea level to determine the spatial distribution of potential tidal inundation. The results indicated that when the Palu-Koro fault remains active, this activity could generate a tidal flood in 2050 and 2100. Flood prediction scenarios suggested that the impact covers central Palu, i.e., Palu Barat and Palu Timur districts, which is almost one-fifth of the research area. Mitigation has taken place through the construction of coastal dikes, except in a few areas.