Abstract
Typhoon Jebi made landfall in Japan in 2018 and hit Osaka Bay on September 4, causing severe damage to Kansai area, Japan’s second largest economical region. We conducted field surveys around the Osaka Bay including the cities of Osaka, Wakayama, Tokushima, Hyogo, and the island of Awaji-shima to evaluate the situation of these areas immediately after Typhoon Jebi struck. Jebi generated high waves over large areas in these regions, and many coasts were substantially damaged by the combined impact of high waves and storm surges. The Jebi storm surge was the highest in the recorded history of Osaka. We used a storm surge–wave coupled model to investigate the impact caused by Jebi. The simulated surge level was validated with real data acquired from three tidal stations, while the wave simulation results were verified with observed data from four wave monitoring stations. The high accuracy of the model demonstrates the usefulness of numerical simulations to estimate the heights of storm surges and wind waves at specific locations, especially where no monitoring stations are available. According to the simulation, the significant wave height was nearly 13 m in the entrance of Kii Strait between Tokushima and Wakayama and 4 m inside Osaka Bay. During the field survey, we encountered collapsed sea dykes, which were obviously damaged by high waves. In fact, the storm surge reached only 1.7 m above the normal tidal level at Kobe, Hyogo, which was not extremely high. Hence, the combination of storm surge and high waves can explain the extent of destruction in Hyogo, such as the failure of an inland floodgate and a stranded large vessel over the breakwater, which were observed during the field survey. We emphasize the importance of adequate coastal designs against high waves even in semi-enclosed bays, as they seem to have been underestimated when the typhoon disaster risk management was conducted.
| Original language | English |
|---|---|
| Pages (from-to) | 4139-4160 |
| Number of pages | 22 |
| Journal | Pure and Applied Geophysics |
| Volume | 176 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 1 Oct 2019 |
Bibliographical note
Funding Information:We are grateful to the Japan Meteorological Agency for providing sea level data for this study (https://www.jma.go.jp/jma/indexe.html) as well as hourly wind field data. This research was funded through the Grant for HT, Tokyo Institute of Technology (Japan Society for the Promotion of Science, 16KK0121 and 19K04964). MH was also funded by the Brunel University London through the Brunel Research Initiative and Enterprise Fund 2017/18 (BUL BRIEF) and the Great Britain Sasakawa Foundation Grant number 5542. LTA appreciates the scholarship from the JICA AUN/SEED-Net.
Funding Information:
We are grateful to the Japan Meteorological Agency for providing sea level data for this study ( https://www.jma.go.jp/jma/indexe.html ) as well as hourly wind field data. This research was funded through the Grant for HT, Tokyo Institute of Technology (Japan Society for the Promotion of Science, 16KK0121 and 19K04964). MH was also funded by the Brunel University London through the Brunel Research Initiative and Enterprise Fund 2017/18 (BUL BRIEF) and the Great Britain Sasakawa Foundation Grant number 5542. LTA appreciates the scholarship from the JICA AUN/SEED-Net.
Publisher Copyright:
© 2019, Springer Nature Switzerland AG.
Keywords
- field survey
- high wave
- Japan
- Kansai
- numerical simulation
- storm surge
- Typhoon Jebi
ASJC Scopus subject areas
- Geophysics
- Geochemistry and Petrology
