The study aims to assess the possible tsunami impact on Yogyakarta, the central coast of Java Island, Indonesia. Seven tsunami scenarios with different parameters estimated by referring the seismic gap and tectonics have been applied to calculate the tsunami propagation, inundation, maximum height and travel time, which are important indices for the assessment. Tsunami numerical modeling was performed by using TUNAMI-N2 with GEBCO bathymetry data. 38 tide gauge stations are selected as output points along Yogyakarta coastal area.
Tsunami simulations with two sources of different depths of 0 km and 10 km using similar sources parameters demonstrated that the depth of source affects the tsunami propagation, maximum tsunami height and inundation area. Through carrying out other simulations with the different parameters such as length and location, we also confirmed that the location and the length of tsunami source caused big difference for the tsunami propagation and tsunami height and inundation area. On the other hand, the catastrophic case (Mw 8.8) adopted from Okal and Synolakis (2007) showed the maximum tsunami height and the widest inundation area compared to the other tsunami sources. Tsunamis could reach the most of coastal area in Yogyakarta in less than 20 min to 50 min after the earthquakes according to the seismic gap.