Assessing transportation vulnerability to tsunamis: utilising post-event field data from the 2011 Tōhoku tsunami, Japan, and the 2015 Illapel tsunami, Chile

Abstract

Abstract. Transportation infrastructure is crucial to the operation of society, particularly during post-event response and recovery. Transportation assets, such as roads and bridges, can be exposed to tsunami impacts when near the coast. Using fragility functions in an impact assessment identifies potential tsunami effects to inform decisions on potential mitigation strategies. Such functions have not been available for transportation assets exposed to tsunami hazard in the past due to limited empirical datasets. This study provides a suite of observations on the influence of tsunami inundation depth, road-use type, culverts, inundation distance, debris and coastal topography. Fragility functions are developed for roads, considering inundation depth, road-use type, and coastal topography and, for bridges, considering only inundation depth above deck base height. Fragility functions are developed for roads and bridges through combined survey and remotely sensed data for the 2011 Tōhoku earthquake and tsunami, Japan, and using post-event field survey data from the 2015 Illapel earthquake and tsunami, Chile. The fragility functions show a trend of lower tsunami vulnerability (through lower probabilities of reaching or exceeding a given damage level) for road-use categories of potentially higher construction standards. The topographic setting is also shown to affect the vulnerability of transportation assets in a tsunami, with coastal plains seeing higher initial vulnerability in some instances (e.g. for state roads with up to 5 m inundation depth) but with coastal valleys (in some locations exceeding 30 m inundation depth) seeing higher asset vulnerability overall. This study represents the first peer-reviewed example of empirical road and bridge fragility functions that consider a range of damage levels. This suite of synthesised functions is applicable to a variety of exposure and attribute types for use in global tsunami impact assessments to inform resilience and mitigation strategies.

Preface: Natural hazard impacts on technological systems and infrastructures

“…They introduce the issue of the visualization of databases, while Petrova (2020) and Frolova et al (2020) also deal with databases of natural hazard impacts on infrastructure, providing useful tools for further research. Williams et al (2020) conclude that the fragility functions show a trend of lower tsunami vulnerability (through lower probabilities of reaching or exceeding a given damage level) for road-use categories of potentially higher construction standards; bridges are more vulnerable to the impacts of tsunamis than roads; however, bridges are better designed to withstand the forces of tsunami loading and have a lower level of vulnerability at all hazard intensities (inundation depth) compared to buildings; culverts represent particularly vulnerable sections of roads. The topographic setting is also shown to affect the vulnerability of transportation assets in a tsunami.…”

“…Braud et al (2020) study runoff hazards in the railway context. Williams et al (2020) assess the vulnerability of transportation to tsunami. Toma-Danila et al (2020) analyze seismic hazards and Mossoux et al (2019) volcanic hazards to road networks.…”

“…The study areas vary from national and interregional scales in North America (Jeong et al, 2019), Brazil (Sayão et al, 2020), Chili, Japan (Williams et al, 2020), and the Russian Federation (Frolova et al, 2020;Petrova, 2020) to regional and local scales in Normandy, France (Braud et al, 2020), the province of Salamanca in Spain (Fluixá-Sanmartín et al, 2019), Bucharest in Romania (Toma-Danila et al, 2020), Hubei Province in China (Chen et al, 2019), and Ngazidja Island, NW of Madagascar (Mossoux et al, 2019).…”

“…The study by Williams et al (2020) represents the first attempt at developing tsunami fragility functions for roads and bridges based on empirical data from two recent tsunami events. Combined survey and remotely sensed data for the 2011 Tōhoku earthquake and tsunami, Japan, and postevent field survey data from the 2015 Illapel earthquake and tsunami, Chile, are analyzed.…”

Tsunami damage to ports: cataloguing damage to create fragility functions from the 2011 Tohoku event

“…Leone et al, 2011;Reese et al, 2011;Mas et al, 2012;Gokon et al, 2014). In recent years, the study of tsunami structural fragility has been extended to critical infrastructure such as roads and bridges (Akiyama et al, 2013;Shoji and Nakamura, 2017;Williams et al, 2020).…”