Sediment scour and deposition within harbors in California (USA), caused by the March 11, 2011 Tohoku-oki tsunami

Borrero

Son

et al. 2014

Geophys. Res. Lett.

Self Cite

The occurrence of tsunami damage is not limited to events causing coastal inundation. Even without flooding, maritime assets are vulnerable to significant damage from strong currents and associated drag forces. While such impacts have been observed in the past, they have not been well studied in any context. Nearshore tsunami currents are governed by nonlinear and turbulent physics and often have large spatial and temporal variability making high-fidelity modeling particularly challenging. Furthermore, measured data for the validation of numerical simulations is limited, with few quality data sets appearing after recent tsunami events. In this paper, we present a systematic approach for the interpretation of measured tsunami-induced current impacts as well as a validation approach for simulation tools. The methods and results provided here lay the foundation for much needed efforts to assess tsunami hazards in ports and harbors.

Section: Introductionmentioning

confidence: 99%

Assessment of the tsunami-induced current hazard

Borrero

Son

et al. 2014

Geophys. Res. Lett.

Self Cite

“…The strong current fields in the harbour areas, including narrow waterways, were successfully generated. In conclusion, the simulated results of bathymetric changes during a tsunami event provide good approximations to the observed records (Wilson et al ., ). Detailed information about the sediment process is also revealed from the simulation results, which is consistent with the data from observations.…”

Section: Discussionmentioning

confidence: 99%

“…Observed (upper left; data from Wilson et al , ) and computed (upper right for D 50 = 0.15 mm; middle left for D 50 = 0.25 mm; middle right for D 50 = 0.35 mm; lower left for D 50 = 0.50 mm; lower right for D 50 = 0.25 mm using SWE model) bathymetric changes at Crescent City Harbor (numbers in metric units; background image is from Google Earth; point A in upper right plot is specified for Figure ). [Colour figure can be viewed at wileyonlinelibrary.com]…”

Section: Field‐scale Application; Far‐field 2011 Tohoku‐oki Tsunamimentioning

confidence: 99%

“…These sedimentation characteristics are also addressed by Wilson et al . (), confirming the present simulation results. More details on tsunami‐related sedimentation will be discussed in the following section.…”

Section: Field‐scale Application; Far‐field 2011 Tohoku‐oki Tsunamimentioning

confidence: 99%

“…The impact becomes much greater when it occurs in a heavily populated coastal region (e.g. Saengsupavanich et al, 2009;Wilson et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Modelling scour and deposition in harbours due to complex tsunami‐induced currents

Son

Earth Surf Processes Landf

Ayça

2020

In this paper, a set of models responsible for hydrodynamics, sediment transport, and morphological evolution are introduced with their theoretical backgrounds, and it is explained how they are fully connected through a two‐way coupling to yield an integrated sediment transport model applicable to tsunami cases. In particular, a fully nonlinear Boussinesq model with bottom shear‐induced rotational terms is chosen for the hydrodynamic model in order to provide a better physical approximation of tsunami‐related, near‐bed hydrodynamics in the nearshore. A finite‐volume scheme, stable and suitable for phase‐resolving model runs longer than 10 simulated hours, is adopted in the numerical discretization. The accuracy and applicability of the developed model are investigated through numerical tests on various sediment problems in the shallow region. Calculated results agree well with existing experimental records. Finally, an ocean‐wide, field‐scale simulation of the 2011 Tohoku‐oki tsunami is attempted, with a focus on the localized effects of tsunami‐induced morphological changes at Crescent City Harbor and Santa Cruz Harbor (USA). Consistent with the reported observations, strong and vortical velocity fields are generated through the model and result in significant changes in morphological configurations. Depth variations and areas of scouring and deposition are compared between modelled and observed records, and the results are discussed. © 2019 John Wiley & Sons, Ltd.

Effect of tides and source location on nearshore tsunami-induced currents

Ayça

J. Geophys. Res. Oceans

2016

Here we present the results of a numerical modeling study that investigates how event‐maximum tsunami‐induced currents vary due to the dynamic effects of tides and wave directivity. First, analyses of tide‐tsunami interaction are presented in three harbors by coupling the tsunami with the tide, and allowing the initial tsunami wave to arrive at various tidal phases. We find that tsunami‐tide interaction can change the event‐maximum current speed experienced in a harbor by up to 25% for the events and harbors studied, and we note that this effect is highly site‐specific. Second, to evaluate the effect of wave directionality on event‐maximum currents, earthquakes sources were placed throughout the Pacific, with magnitudes tuned to create the same maximum near‐coast amplitude at the harbor of study. Our analysis also shows that, for the harbor and sources examined, the effect of offshore directionality and tsunami frequency content has a weak effect on the event‐maximum currents experienced in the harbor. The more important dependency of event‐maximum currents is the near‐harbor amplitude of the wave, indicating that event‐maximum currents in a harbor from a tsunami generated by a large far‐field earthquake may be reasonably well predicted with only information about the predicted local maximum tsunami amplitude. This study was motivated by the hope of constructing a basis for understanding the dynamic effects of tides and wave directivity on current‐based tsunami hazards in a coastal zone. The consideration of these aspects is crucial and yet challenging in the modeling of tsunami currents.