Breakwater Effects on Tsunami Inundation Reduction in the 2011 off the Pacific Coast of Tohoku Earthquake

Tomita, Takashi; Yeom, Gyeong-Seon; Ayugai, Motokazu; Niwa, Tatsuya

doi:10.2208/kaigan.68.i_156

Cited by 9 publications

(4 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…and should play a secondary role in slowing the advance of the tsunami and providing residents with extra time to evacuate (Tomita et al, 2012). For example, in the case of Otsuchi town, in Iwate prefecture, prior to the 2011 event the highest tsunami walls were built up to a height of +6.4 m T.P.…”

Section: Introductionmentioning

confidence: 99%

“…One of the more significant of such structures was the Kamaishi tsunami breakwater, the deepest breakwater built anywhere in the world. Following the disaster, Tomita et al (2012) conducted simulations that show that the structure could have reduced inundation heights in Kamaishi city from 13.7 m to 8.0 m, providing residents an extra 6 minutes to evacuate (though the effect of damaged sections of this breakwater was neglected in the calculations of tsunami approach time, Cyranoski, 2012). However, other more typical breakwaters were basically designed to reflect wind waves, and the reduction of the tsunami impact due to them should also not be overestimated (Takagi and Bricker, 2014).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of bed roughness on tsunami bore propagation and overtopping

Esteban

Roubos

Iimura

et al. 2020

Coastal Engineering

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of bed roughness on tsunami bore propagation and overtopping

Esteban

Roubos

Iimura

et al. 2020

Coastal Engineering

View full text Add to dashboard Cite

“…The bay mouth breakwaters listed in S1 Table were also damaged. Despite the damage these coastal facilities experienced, [ 15 , 22 ] showed these structures delayed tsunami arrival time by several minutes, thus affording residents more time to evacuate. The structures also reduced overland inundation extent, depth, and flow speed, reducing the number of homes destroyed.…”

Section: Data Collection and Visualizationmentioning

confidence: 99%

“…Contrarily, Tomita et al [ 15 ] showed that the Kamaishi and Ofunato breakwaters, even in their post-tsunami damaged state, significantly reduced the extent of each town flooded by the tsunami, mitigated flow speed and depth in the inundated areas, and delayed tsunami arrival time long enough to aid the evacuation of residents. Furthermore, others cite the example of Fudai, where a large river-mouth gate saved the town from destruction [ 16 ].…”

Section: Introductionmentioning

confidence: 99%

Statistical Analysis of the Effectiveness of Seawalls and Coastal Forests in Mitigating Tsunami Impacts in Iwate and Miyagi Prefectures

et al. 2016

View full text Add to dashboard Cite

The Pacific coast of the Tohoku region of Japan experiences repeated tsunamis, with the most recent events having occurred in 1896, 1933, 1960, and 2011. These events have caused large loss of life and damage throughout the coastal region. There is uncertainty about the degree to which seawalls reduce deaths and building damage during tsunamis in Japan. On the one hand they provide physical protection against tsunamis as long as they are not overtopped and do not fail. On the other hand, the presence of a seawall may induce a false sense of security, encouraging additional development behind the seawall and reducing evacuation rates during an event. We analyze municipality-level and sub-municipality-level data on the impacts of the 1896, 1933, 1960, and 2011 tsunamis, finding that seawalls larger than 5 m in height generally have served a protective role in these past events, reducing both death rates and the damage rates of residential buildings. However, seawalls smaller than 5 m in height appear to have encouraged development in vulnerable areas and exacerbated damage. We also find that the extent of flooding is a critical factor in estimating both death rates and building damage rates, suggesting that additional measures, such as multiple lines of defense and elevating topography, may have significant benefits in reducing the impacts of tsunamis. Moreover, the area of coastal forests was found to be inversely related to death and destruction rates, indicating that forests either mitigated the impacts of these tsunamis, or displaced development that would otherwise have been damaged.

show abstract

A comprehensive review on structural tsunami countermeasures

et al. 2022

View full text Add to dashboard Cite

Tsunamis pose a substantial threat to coastal communities around the globe. To counter their effects, several hard and soft mitigation measures are applied, the choice of which essentially depends on regional expectations, historical experiences and economic capabilities. These countermeasures encompass hard measures to physically prevent tsunami impacts such as different types of seawalls or offshore breakwaters, as well as soft measures such as long-term tsunami hazard assessment, tsunami education, evacuation plans, early-warning systems or coastal afforestation. Whist hard countermeasures generally aim at reducing the inundation level and distance, soft countermeasures focus mainly on enhanced resilience and decreased vulnerability or nature-based wave impact mitigation. In this paper, the efficacy of hard countermeasures is evaluated through a comprehensive literature review. The recent large-scale tsunami events facilitate the assessment of performance characteristics of countermeasures and related damaging processes by in-situ observations. An overview and comparison of such damages and dependencies are given and new approaches for mitigating tsunami impacts are presented.

show abstract

Breakwater Effects on Tsunami Inundation Reduction in the 2011 off the Pacific Coast of Tohoku Earthquake

Cited by 9 publications

References 0 publications

Effect of bed roughness on tsunami bore propagation and overtopping

Effect of bed roughness on tsunami bore propagation and overtopping

Statistical Analysis of the Effectiveness of Seawalls and Coastal Forests in Mitigating Tsunami Impacts in Iwate and Miyagi Prefectures

A comprehensive review on structural tsunami countermeasures

Contact Info

Product

Resources

About