Tsunami Numerical Modelling in Ujung Kulon National Park with the Earthquake Magnitude Scenario of 6.5 and 6.9 Mw

Abstract

Abstract Tsunami modelling was conducted to simulate tsunami events based on earthquake data previously occurring around Ujung Kulon National Park (TNUK), Banten Province using TUNAMI-F1 and TUNAMI-N3. TUNAMI-F1 is a modelling method to get the wave height and tsunami arrival time with a grid spacing of 0.00167°. While the TUNAMI-N3 is a model that applies the theory of wave propagation linearly in a grid variation to get a high output of tsunami inundation. The tsunami source data was used from historical earthquake generation on January 14, 2022 (6.5 Mw) and August 2, 2019 (6,9 Mw). The reverse fault type scenario from Wells & Coppersmith (1994) is used to calculate the scaling law with length, width, and the focal mechanism value obtained from the United States Geological Survey (USGS) to generate initial waves based on the multideform model. The TUNAMI-N3 model applies a nested model with variations in grid spacing and the most detailed value is 68,556 m. The tsunami wave height based on the magnitude 6.5 Mw scenario is around 0.001 m to 0.05 m with the highest wave height found on the southern coast of TNUK and the southern coastal area of Peucang Island (0.03-0.05m). The inundation produced is only visible in the E1 domain reaching 96-192 m in areas A, B, C. Then, the maximum inundation area is the south coast of TNUK (0.01-0.03m). Based on the second scenario, the height of the tsunami waves generated is in the range of 0.001 − 0.3 m. The maximum tsunami height was in the Rancecet Beach area, south of Tinjil Island, the south, east, and north coasts of TNUK (0.03-0.3m). The run-up distance resulting from scenario 1 is less than 1 km. Based on TUNAMI-F1 model results, wave height maximum caused by 6.5 Mw magnitude is higher than 6.9 Mw.