Measuring offshore tsunami currents using ship navigation records

Inazu, Daisuke; Ikeya, Tsuyoshi; Waseda, Takuji; Hibiya, Taketoshi; Shigihara, Yoshinori

doi:10.1186/s40645-018-0194-5

Cited by 20 publications

(29 citation statements)

References 66 publications

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“…We use AIS data during the 2011 Tohoku, Japan, tsunami, which are the same data as used in the authors' former research (Inazu et al 2018). Based on the International Convention for the Safety of Life at Sea (SOLAS), vessels whose gross tonnages are basically greater than 300 gross tonnages have obligation to transmit AIS messages using very-high-frequency (VHF) maritime bands (IMO 2002(IMO , 2016.…”

Section: Ais Datamentioning

confidence: 99%

“…Labeled 13 ships (#1-#13) are used to evaluate tsunami currents in this study (Table 1). Another three ships (*1-*3) are not used due to data quality issues (Inazu et al 2018). Dashed isobaths of 100 m and 500 m are shown in addition to the Japan Trench.…”

Section: Ais Datamentioning

confidence: 99%

“…One is given by Saito et al (2011) which estimated an instant tsunami generation. The result was used in Inazu et al (2018). The other is given by Hossen et al (2015) which estimated a dynamic tsunami generation during 3 min.…”

Section: Ais Datamentioning

confidence: 99%

“…These facilities are mostly deployed for the purpose of monitoring coastal ocean circulations with wide applications (Roarty et al 2019). Inazu et al (2018) found that tsunami currents could be detected using navigation data derived from the Automatic Identification System (AIS). They demonstrated a feasibility of tsunami detectors from crowd-sourced moving vessels.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, AIS data are aggregated from a large number of unspecified vessels thanks to regulations of the International Maritime Organization (IMO 2016). We have investigated this versatile AIS for tsunami current measurements (Inazu et al 2018). In the present study, a more efficient method incorporating ship motions is demonstrated to detect clearer tsunami currents.…”

Section: Introductionmentioning

confidence: 99%

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Extracting clearer tsunami currents from shipborne Automatic Identification System data using ship yaw and equation of ship response

Inazu

Ikeya

Iseki

et al. 2020

Earth Planets Space

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We have explored tsunami current signals in maritime Automatic Identification System (AIS) data during the 2011 Tohoku, Japan, tsunami. The AIS data were investigated in detail taking into account ship motion and response to tsunami current. Ship velocity derived from AIS data was divided into two components in terms of the ship heading: heading-normal and heading-parallel directions. The heading-normal velocity showed good agreement with the simulated tsunami current, as mentioned in our former research. Here, we found the heading-normal velocity was contaminated by non-tsunami noises that were mostly related to the ship yaw motion around the pivot point. The noises due to the yaw motion were reasonably corrected in the heading-normal velocity. The corrected headingnormal velocity clearly showed better agreement with the simulated tsunami current. Although the heading-parallel velocity is basically the navigation speed, and is mostly controlled by ships' captain, we could find the heading-parallel velocity was also drifted by tsunami currents. The corrected heading-normal velocity was still a ship response to the tsunami current. Based on an equation of a ship response to tsunami currents, we numerically estimated tsunami current from the corrected heading-normal velocity. We could find very slight improvements in estimating the tsunami currents, which indicated that this operation possibly worked as a secondary correction. Tsunami currents of tens of centimeters per second are expected to be suitably detected using AIS based on discussion on detection limit.

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Section: Ais Datamentioning

confidence: 99%

Section: Ais Datamentioning

confidence: 99%

Section: Ais Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Extracting clearer tsunami currents from shipborne Automatic Identification System data using ship yaw and equation of ship response

Inazu

Ikeya

Iseki

et al. 2020

Earth Planets Space

Self Cite

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Review on Recent Progress in Near-Field Tsunami Forecasting Using Offshore Tsunami Measurements: Source Inversion and Data Assimilation

Wang

Tsushima

Satake

et al. 2021

Pure Appl. Geophys.

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Traditional tsunami forecasting methods are based on seismic observations. The development of offshore observational devices makes it possible to utilize offshore tsunami measurements for providing early warnings. This paper reviews the tsunami data-oriented forecasting methods of two main types: tsunami source inversion and tsunami data assimilation. In the first type, offshore tsunami measurements are used to enhance and speed up the traditional tsunami source inversion methods. The effectiveness and uncertainties of the tsunami source estimation are discussed. In the second type, tsunami data assimilation, the wavefield is directly reconstructed and forecasted without considering the source. We review the techniques that are adopted to improve the speed and accuracy of data assimilation and to determine the optimal design for an ocean bottom pressure gauge (OBPG) network. It is important for tsunami data-oriented forecasting methods to accurately extract tsunami signal in real time, particularly when the OBPG is located inside the source area.

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Combined hazard of typhoon-generated meteorological tsunamis and storm surges along the coast of Japan

Heidarzadeh

Rabinovich

2020

Nat Hazards

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Two hazardous typhoons, Lionrock (August 2016) and Jebi (September 2018), destructively affected the coast of Japan and produced extreme sea level variations. The results of field surveys in the impacted regions showed that multiple deaths and extensive floods were caused by the combined effect of low-frequency sea level raise (storm surges) and intensive high-frequency (HF) tsunami-like waves (meteotsunamis). The data from ten tide gauges for the 2016 event and eight gauges for the 2018 event were used to examine the properties of the observed sea levels, to estimate the relative contribution of the two sea level components and to evaluate their statistical characteristics (maximum wave heights, amplitudes and periods of individual components, etc.). For the 2016 event, we found that the surge heights were from 12 to 35 cm and that the mean contribution of surges into the total observed sea level heights was ~ 39%; the meteotsunami amplitudes were from 22 to 92 cm, and they contributed 61% of the total height. For the 2018 event, storm surges were significantly stronger, from 46 to 170 cm, while HF amplitudes were from 38 to 130 cm; their relative inputs were 67% and 33%, respectively. Combined, they formed total flood heights of up to 120 cm (2016 event) and 288 cm (2018 event). Previously, the contribution of storm seiches (meteotsunamis) in coastal floods had been underestimated, but results of the present study demonstrate that they can play the principal role. What is even more important, they produce devastating currents: according to our estimates, current speeds were up to 3 knots (1.5 m/s) during the Lionrock event and more than 5 knots (2.6 m/s) during Jebi; these strong currents appear to be the main reason for the resulting damage of coastal infrastructure. The most important characteristic of the recorded meteotsunamis is their trough-to-crest maximum height. During the 2016 event, these heights at three stations were > 1 m: 171 cm at Erimo, 109 cm at Hachijojima and 102 cm at Ayukawa. The 2018 event was stronger; maximum meteotsunami wave heights were 257 cm at Gobo, 138 cm at Kushimoto, 137 cm at Kumano and 128 cm at Murotomisaki. The 2018 Gobo height of 257 cm is much larger than historical non-seismic seiche maxima for the Pacific coast of Japan (140–169 cm) estimated by Nakano and Unoki (1962) for the period of 1930–1956.

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Measuring offshore tsunami currents using ship navigation records

Cited by 20 publications

References 66 publications

Extracting clearer tsunami currents from shipborne Automatic Identification System data using ship yaw and equation of ship response

Extracting clearer tsunami currents from shipborne Automatic Identification System data using ship yaw and equation of ship response

Review on Recent Progress in Near-Field Tsunami Forecasting Using Offshore Tsunami Measurements: Source Inversion and Data Assimilation

Combined hazard of typhoon-generated meteorological tsunamis and storm surges along the coast of Japan

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