Tsunami simulation in Puger Beach considering the combination of earthquake source in South Java

Abstract

Tsunami occurred on June 3, 1994, as a result of the earthquake in Banyuwangi at 10,477° South Latitude and 112,835° East Longitude with magnitude 7.2 SR. Tsunami in Banyuwangi causes 122 victims, 15 missing persons, 450 houses completely ruined, over 250 heavily damaged in Pancer village and 6 fishermen disappear. In 2006, The Pangandaran Tsunami also attacked coastal area in South Java. This study aims to model tsunami in Puger Beach using Delft3D with the combination of earthquake source characteristics in South Java. Bathymetry data and topography were taken from The General Bathymetric Chart of the Oceans (GEBCO). Delft3D Dashboard was utilized as a first step to create a model domain and simulation grid. Bathymetric interpolation to the simulation grid and initial surface elevation were also created from earthquake fault parameters using Delft3D Dashboard. After setting parameters, numerical simulation was carried out using Delft3D-FLOW. To conduct model validation, the data observation of the 1994 Banyuwangi tsunami from the previous research was utilized. The locations used for validation in this study were Cape Pelindu, Puger and Watu Ulo Beaches with the maximum water level 3.2 m, 4.88 m - 5.85 m and 6.5 m - 7.5 m, respectively. Simulations were divided into three scenarios. Scenario 1 was a simulation of the 1994 Banyuwangi tsunami. Scenario 2 was a simulation to represent the characteristic of fault from The 2006 Pangandaran Earthquake in Puger Beach. Scenario 3 was a combination between Scenario 1 and Scenario 2 which represented tectonic plate fault simulation. Based on the results of the simulation 3, the time of maximum tsunami height reached the study area at the 40 minutes and back to normal at 170 minutes. The greatest impact was created from Scenario 3 with tsunami heights of 10.91 meters to 22.34 meters.