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Soft measures such as evacuation planning are recommended to mitigate the loss of life during tsunamis. Two types of evacuation models are widely used: (i) agent-based modelling (ABM) defines sets of rules that individual agents in a simulation follow during a simulated evacuation; and (ii) geographical information systems (GIS) are more accessible to city planners, but cannot incorporate the dynamic behaviours found in ABMs. The two evacuation modelling methodologies were compared through a case study by assessing the state of evacuation preparedness and investigating potential mitigation options. The two models showed different magnitudes for mortality rates and facility demand but had similar trends. Both models agreed on the best solution to reduce the loss of life for the community. GIS may serve as a useful tool for initial investigation or as a validation tool for ABMs. ABMs are recommended for use when modelling evacuation until GIS methodologies are further developed. Key words: evacuation model, agent-based model, GIS model, tsunami inundation, coastal hazards. Des mesures souples, comme la planification d'evacuation, sont recommandees pour attenuer les pertes de vie lors de tsunamis. Deux types de modeles d'evacuation sont largement utilises : (i) la modelisation fondee sur les agents (MFA) definit des ensembles de regles que les agents individuels d'une simulation suivent pendant une evacuation simulee tandis que (ii) les systemes d'information geographique (SIG) sont plus accessibles aux urbanistes, mais ne peuvent integrer les comportements dynamiques des MFA. Les deux methodes de modelisation d'evacuation ont ete comparees au moyen d'une etude de cas en evaluant l'etat de preparation a l'evacuation et en examinant les options d'attenuation possibles. Les deux modeles presentaient des ampleurs differentes pour les taux de mortalite et la demande d'installations, mais des tendances semblables. Les deux modeles concordaient quant a la meilleure solution pour reduire les pertes de vie dans la collectivite. Les SIG peuvent servir d'outil pour l'enquete preliminaire ou comme outil de validation pour les MFA. Il est recommande d'utiliser les MFA lors de la modelisation d'evacuation jusqu'a ce que les methodologies de SIG soient developpees davantage. [Traduit par la Redaction] Mots-cles : modele d'evacuation, modele fonde sur les agents, modele de systeme d'information geographique (SIG), inondation par tsunami, dangers cotiers., 1. Introduction 1.1. Evacuation planning as a tsunami mitigation measure In Japan, hard-structural tsunami mitigation measures such as the Kamaishi breakwater and other seawalls protecting the coastal areas experienced partial [...]

On January 1 2024, at 16:10 JST, an earthquake of Mw 7.5 occurred underneath the Noto Peninsula of Ishikawa Prefecture, Japan. This event caused a cascading disaster impact on cities in the Noto Peninsula through a series of strong earthquake shakes, strong ground motions, slope failures, liquefaction, fire, and tsunamis. The tsunami first reached Suzu City a few minutes after the earthquake, eventually affecting approximately 340 km of the coast from the Ishikawa to Niigata Prefectures. The Coastal Engineering Committee of the Japan Society of Civil Engineers conducted an organized post-event field survey to understand the impact of tsunamis on land. This study summarizes the post-event field survey results and provides a general understanding of tsunami behavior and damage using measured tsunami inundation and run-up heights. [ABSTRACT FROM AUTHOR]

Hydraulic experiments using a wave flume with a wind tunnel at a scale of 1/40 were carried out to investigate the effect of wind on wave overtopping of a vertical seawall. To ascertain the possible effects of wave breaking, incident waves with various wave steepness (0.0102 to 0.0371) and three kinds of wind forcing (0 m/s, 6.84 m/s, 10.04 m/s) were used. The authors found that winds significantly increased the overtopping rate in general, and that there is a clear relationship between the overtopping rate and the wave steepness. Velocity fields obtained from PIV analysis revealed that the onshore winds directly enhanced the transport of overtopping water mass. The influence of the wind on the wave hydrodynamic processes that indirectly have an effect on the overtopping rate (such as the formation of a partially standing wave, breaker location, and breaker type) is also discussed. The perspective of treating wave overtopping as a transport of water mass could provide a novel understanding of complex fluid behavior, which would help to formulate countermeasures against future disasters influenced by intensive wind forcing. [ABSTRACT FROM AUTHOR]

The actions of wind and atmospheric pressure associated with tropical cyclones (e.g. typhoons) are considered the primary factors behind the generation of storm surges, though the fields used in meteorological models can sometimes deviate from observations. To improve these, the direct modification method (DMM) has been previously proposed, though this only modifies the wind field of a typhoon, and further development is necessary for applying it to storm surge hindcasts. The present work describes the development of a semi-empirical gradient wind balance-based method (GWB-M) for modifying both the wind and pressure fields in meteorological models, based on the dynamic relationship between the wind and pressure in typhoons (i.e. gradient wind balance). The applicability of GWB-M was assessed through a storm surge hindcast based on Typhoon Faxai in 2019, which generated powerful waves and a storm surge at Tokyo Bay. GWB-M improved the time series of 10 m wind speed and sea level pressure, with their spatial distributions being more realistic than those in DMM and blending parametric typhoon models (BM), which cannot take into account the influence of the complex topography around Tokyo Bay. Further, the maximum sea level anomalies after the typhoon made landfall were also captured by GWB-M with a higher accuracy than DMM. [ABSTRACT FROM AUTHOR]