Supplementary Information for “A Tsunami Warning System based on Offshore Bottom Pressure Gauges and Data Assimilation for Crete Island in the Eastern Mediterranean Basin”
Yuchen Wang1, Mohammad Heidarzadeh2, Kenji Satake1, Iyan E. Mulia1, and Masaki Yamada3
1Earthquake Research Institute, The University of Tokyo, Tokyo, Japan.
2Department of Civil & Environmental Engineering, Brunel University London, Uxbridge UB8 3PH, UK.
3Department of Geology, Faculty of Science, Shinshu University, Nagano, Japan.
Corresponding author: Yuchen Wang (ywang@eri.u-tokyo.ac.jp)
Comparisons of Tsunami Waveforms by Two-Layer/JAGURS Models
In this supplementary information, we compare the tsunami waveforms at Offshore Bottom Pressure Gauges (OBPGs) and tide gauges, which are simulated with different initial conditions in the propagation phase.
In our study, the generation phase (\(t=\) 0 – 5 min) of landslide tsunamis is simulated by the two-layer model. For the propagation phase, we adopt different models with different initial conditions: the two-layer model (Kawamata et al., 2005; Ren et al., 2020) andJAGURS model (Satake, 1995; Baba et al., 2015). In the two layer-model, the surface elevation and the horizontal velocities at the end of landslide generation phase (\(t=\) 5 min) are both used as the initial condition. We only consider the upper layer (sea-water layer) for the propagation phase modelling. However, in JAGURS model, we only use the surface elevation as the initial condition, becauseJAGURS model cannot load initial velocities (Baba et al., 2015). In both models, we compute the tsunami propagation in the region of 34.0−38.0\(N\), 20.0−30.0\(E\). The grid resolution is 30 arc sec, and the time step is 1 s. We simulate the tsunami propagation until 180 min after the landslide. The waveforms at OBPGs and tide gauges are recorded.
Figures S1 and S2 show the comparisons of tsunami waveforms at OBPGs and tide gauges, respectively. Blue curves indicate the tsunami whose propagation phase is simulated by the two-layer model, with the consideration of horizontal velocities at the end of landslide generation phase (\(t=\) 5 min). Red curves indicate the results ofJAGURS model. In both figures, the waveforms simulated by two models are very similar. The tsunami simulated by the two-layer model arrives only slightly earlier than the one by JAGURS model. Hence, our results indicate that the horizontal velocities at the end of landslide generation phase is negligible for tsunami propagation modeling.