Tidal and bathymetry characteristics after the 2018 earthquake and tsunami in Watusampu Waters, Palu Bay, Central Sulawesi

The Watusampu Water Coast was one of the waters affected by the tsunami waves on September 28, 2018. The height of the tsunami waves reached 6.6 meters and submerged as far as 71.4 meters inland. This study aims to see the bathymetry and tidal characteristics of Watusampu waters after the 2018 tsunami. The results of bathymetry measurements are corrected with tidal data. The results of tide measurements are compared with the predicted results and then analyzed by T-tide to calculate the tidal constituents used in the calculation of the planned water level in Watusampu waters. The bathymetry depth in the Watusampu waters ranges from 66.5 meters. The slope of the coastal waters has increased from north to south. The type of tide in Watusampu waters is mixed tides with a double daily inclination. The dominant tidal constituents are M2 and S2, respectively, with an amplitude of 0.5336 m and 0.4025 m. The tide wave height at the neap tide and spring tide is 0.2622 and 1.8722 m, respectively.