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.