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A Tsunami Warning System based on Offshore Bottom Pressure Gauges and Data Assimilation for Crete Island in the Eastern Mediterranean Basin
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  • Yuchen Wang,
  • Mohammad Heidarzadeh,
  • Kenji Satake,
  • Iyan Eka Mulia,
  • Masaki Yamada
Yuchen Wang
University of Tokyo

Corresponding Author:ywang@eri.u-tokyo.ac.jp

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Mohammad Heidarzadeh
Brunel University London
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Kenji Satake
University of Tokyo
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Iyan Eka Mulia
University of Tokyo
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Masaki Yamada
Shinshu University
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Abstract

The Eastern Mediterranean Basin (EMB) is under the threat of tsunami events triggered by various causes including earthquakes and landslides. We propose a deployment of Offshore Bottom Pressure Gauges (OBPGs) around Crete Island, which would enable tsunami early warning by data assimilation for disaster mitigation. Our OBPG network consists of 12 gauges distributed around Crete Island. The locations of OBPGs are confirmed by Empirical Orthogonal Function (EOF) analysis of the pre-calculated tsunami scenarios, and most of them are placed at the locations where the most energetic wave dynamics occur. We demonstrate three test cases comprising a hypothetical seismogenic tsunami in east Sicily, a hypothetical landslide tsunami in the Aegean Sea, and the real tsunami event of the May 2020 off the Crete earthquake. Our designed OBPG network achieves a forecasting accuracy of 88.5 % for the hypothetical seismogenic tsunami and 85.3% for the hypothetical landslide tsunami with warning lead times of 10-20 min for both cases. For the real event of May 2020, it predicts the tsunami arrival at tide gauge NOA-04 accurately; the observed and forecasted amplitudes of the first wave are 5.0 cm and 4.5 cm, respectively. The warning lead time for the May 2020 event was ~10 min. Therefore, our results reveal that the assimilation of OBPG data can satisfactorily forecast the amplitudes and arrival times for tsunamis in the EMB. We note that further studies are necessary to examine the relation between the performance of the system and the number of OBPGs or the tsunami characteristics.
Oct 2020Published in Journal of Geophysical Research: Solid Earth volume 125 issue 10. 10.1029/2020JB020293