Deformation of Sandy Beach and Inundation on Iwama-Sanuka Coast in Fukushima Prefecture due to the 2011 Tohoku Earthquake Tsunami

2012 ◽  
Vol 7 (sp) ◽  
pp. 476-484 ◽  
Author(s):  
Takaaki Uda ◽  
◽  
Kazuya Sakai ◽  
Yukiyoshi Hoshigami ◽  
Yasuhito Noshi ◽  
...  

The massive earthquake with a magnitude of 9.0 occurred at 14:46 on March 11, 2011, with an epicenter 130 km offshore from the Oshika Peninsula in Japan’s northeastern Miyagi Prefecture. After the earthquake, large tsunamis were generated owing to abrupt crustal subsidence and uplift, which inundated Japan’s eastern Pacific Ocean coastline. We carried out field observations to investigate the deformation of a previous river-mouth bar by comparing oblique photographs, and investigated the damage to seawalls and the tsunami inundation depth on the Iwama-Sanuka coast, located north of the Same River in southern Fukushima Prefecture. Here, the results of the field observations on the deformation of the sandy beach and the inundation of the Iwama-Sanuka coast are reported.

2013 ◽  
Vol 8 (4) ◽  
pp. 573-583 ◽  
Author(s):  
Yusuke Suga ◽  
◽  
Shunichi Koshimura ◽  
Ei-ichi Kobayashi ◽  
◽  
...  

Drifting ship due to tsunami inundation flow may cause additional damage in harbor area. Many drifting ships were found in the 2011 Great East Japan earthquake tsunami and these caused various problems (damage of ships themselves, striking other structures and obstacle for restoration). In this sense, it is very important for disaster prevention to predict the drifting motion of a large ship by tsunami current. This study aims to simulate the drifting motion of ships by the 2011 Tohoku earthquake tsunami in Kesennuma harbor, Miyagi Prefecture. First, we simulated the hydrodynamic features of the 2011 tsunami by numerical simulation. Secondly, we analyzed the drifting motion of large ships using the result of tsunami numerical simulation. In the analysis, several test cases were conducted by changing parameter and initial position of the ship. Then we verified the results of the ship drifting simulation by comparing with actual grounding position of ships. Throughout the comparisons and verifications, we found the grounding position by the simulation was generally consistent with actual position of ships. Although it is necessary to verify the drifting route of ships, the results suggest that this model is beneficial for future disaster prevention.


Author(s):  
Takuya Miyashita ◽  
Nobuhito Mori

The inundation of the 2011 Tohoku Earthquake Tsunami showed complex behavior over the land. According to the surveys of the Tohoku Earthquake Tsunami in 2011, the behavior of tsunami in urban areas was different from that in rural areas and the damage was not only dependent on the inundation heights but also the local momentum. The buildings are commonly excluded and smoothed off in the topography in the conventional inundation simulation but it’s important to understand the local characteristics of tsunami run-up in urban areas. The purpose of this study is to understand and validate numerical models of tsunami in the urban area.


Recycling ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 56
Author(s):  
Naoharu Murasawa

Following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident caused by the 2011 Tōhoku earthquake and tsunami, radioactive caesium (r-Cs) was detected in the ash generated by municipal solid waste (MSW) incineration facilities in Fukushima Prefecture. This has led to concerns of r-Cs leaching and subsequent environmental contamination during recycling or landfill disposal. Therefore, it is crucial that the relevant authorities have a thorough understanding of r-Cs leaching behavior to establish suitable prevention methods. In this study, we collected r-Cs-contaminated fly and bottom ash (FA and BA) samples from five MSW incineration facilities in Fukushima Prefecture and conducted tests to clarify their basic physical properties and r-Cs leaching properties. We also examined the possibility of preventing r-Cs leaching by adding 5 wt% acid clay to the FA. FA had greater chloride content and r-Cs leaching rate than BA and was found to absorb moisture and deliquesce when stored under high-humidity conditions. However, the addition of acid clay effectively prevented r-Cs leaching upon contact with moisture. From the results, we propose some specific recommendations to counter the leaching of r-Cs from FA at MSW incineration facilities, which will limit r-Cs leaching during recycling or landfill processes.


2016 ◽  
Vol 32 (4) ◽  
pp. 1989-2007 ◽  
Author(s):  
Kohji Tokimatsu ◽  
Michitaka Ishida ◽  
Shusaku Inoue

A simulation of the tsunami run-up during the 2011 Great Tohoku Earthquake was performed to investigate the mechanisms and differences in overturning failures of buildings in Onagawa, based on a two-dimensional (2-D) shallow water equation with video evidence recorded in the town as reference. The time histories of inundation depth and flow velocity predicted by the analysis enable one to develop a simplified method to estimate the hydrodynamic and buoyant forces acting on a building, as well as its factors of safety against sliding, uplift, and overturning in the time domain. This method was applied to five well-documented cases of buildings that did or did not overturn during the tsunami. Results showed that the proposed method is capable of predicting the differences in building performance qualitatively, including the likelihood, time, and direction of toppling. The results also suggested that the seaward overturning of one building is likely due to its specific topographical location with a hill closely behind that makes the tsunami load significantly less during run-up than during backwash.


2020 ◽  
Vol 20 (2) ◽  
pp. 451-470 ◽  
Author(s):  
James H. Williams ◽  
Thomas M. Wilson ◽  
Nick Horspool ◽  
Ryan Paulik ◽  
Liam Wotherspoon ◽  
...  

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.


Author(s):  
Ken Hatayama

The Mw9.0 2011 Tohoku, Japan earthquake tsunami damaged 418 oil storage tanks located along the Pacific coast of the Hokkaido, Tohoku, and Kanto Districts of Japan. A wide variety of damage was observed, including movement and deformation of the tank body, scouring of the tank base and ground, and movement or structural fracture of the pipe. In total, 157 of the 418 tanks were moved by the tsunami. By comparing the severity of damage with the inundation depth of the tsunami experienced by the oil storage tank, a fragility curve projecting the damage rate for plumbing is presented, and a rough but easy-to-use method of predicting tsunami damage to an oil storage tank from a given inundation depth is also presented: (i) for inundation depths of 2–5 m, tanks suffer damage to their plumbing, and small tanks (capacity < 100 m3) and empty larger tanks may be moved; (ii) for inundation depths of greater than 5 m, most tanks are moved. The validity of the previously-proposed tsunami tank-movement prediction method is first examined. A comparison of the method’s predictions with the actual damage data from the 2011 Tohoku earthquake tsunami indicates a high hit rate of 76%.


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