A numerical computation of the 2011 Tohoku earthquake tsunami was performed to identify fundamental features evolution along coast Hokkaido, Japan. Edge waves formed at multiple locations where refracted focused, governing local surface oscillations and regional variations in height Pacific Hokkaido. The reasonably reproduced distribution surveyed as well time records elevation recorded ports major frequency spectrum for were identical those 2003 Tokachi-oki tsunami; inherent properties...

This study proposes a new embankment reinforcement using steel sheet piles against tsunami overflow, which has been known as the main cause of failures embankments by 2011 Tohoku Earthquake Tsunami. Effectiveness proposed technique was discussed through hydraulic experiment. A model set in horizontal open channel, and one or two plates are installed into from top vertical walls inside. Temporal variations shapes pile structures were obtained video images. In most cases, started to rotate...

A lot of coastal dikes located along the Pacific Coast Tohoku Region were severely damaged by Great East Japan Earthquake Tsunami. In this study, hydraulic model experiments conducted to understand characteristics local scour at a landward toe dike, which has been considered as main cause failures 2011 tsunami. dike is fixed in horizontal open channel with 4.5m length. Scouring sandy bed behind under constant discharge recorded video camera and temporal variations sizes hole are extracted...

Duy, D.V.; Tanaka, H.; Mitobe, Y.; Anh, N.Q.D., and Viet, N.T., 2018. Sand spit elongation sediment balance at Cua Lo Inlet in Central Vietnam. In: Almar, R.; Almeida, L.P.; Trung N., Sall, M. (eds.), Tropical Coastal Estuarine Dynamics. Journal of Research, Special Issue No. 81, pp. 32–39. Coconut Creek (Florida), ISSN 0749-0208.Erosion is significant on the downdrift beach Inlet, which located The Inlet's updrift sand together with severe erosion bank raising numerous social problems such...

It is inevitable to find in studies that shoreline position extracted from unknown capture time aerial photograph or satellite image was not corrected tidal effect. In this study, an approach introduced can estimate the of solar azimuth angle and length shadow a vertical object on horizontal surface earth. The tze estimated has much smaller deviation than one shadow. This error acceptable for correction purposes. also utilized set images Sendai coast. Therefore, implemented positions those images.

Tsunami-related fires may occur in the inundation area during a huge tsunami disaster, and woody debris produced by can cause to spread. To establish practical method for evaluating tsunami-related fire predictions, we previously developed thickness distribution that uses computation results static parameters numerical analysis. We then used this evaluation successfully reproduce accumulation trend. an empirical building fragility function relates production of not only depth but also...

A novel imaging technique for identifying the locations of free-surface shapes was applied to three-dimensional hydraulic tests coastal structures. Three-dimensional wave fields, consisting superposed local reflected and diffracted waves, were measured around a breakwater mouth model harbor in laboratory basin, results are consistent with predictions Boussinesq-type equation model. The new surf zone waves describe organized deformation breaking faces that evolve during propagation. Typical...

Thanh, T.M.; Tanaka, H.; Mitobe, Y.; Viet, N.T., and Almar, R., 2018. Seasonal variation of morphology sediment movement on Nha Trang Coast, Vietnam. In: R.; Almeida, L.P.; Trung N., Sall, M. (eds.), Tropical Coastal Estuarine Dynamics. Journal Research, Special Issue No. 81, pp. 22–31. Coconut Creek (Florida), ISSN 0749-0208.The beach, an embayed sandy beach located in the southeast Vietnam, is a tropical touristic coastal environment that being threat by persistent shoreline retreat. In...

Adityawan, M.B.; Tanaka, D., Mitobe, Y., and Widiyanto, W., 2016. A new computation method of bottom shear stress under tsunami waves, In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., McCarroll, R.J. (eds.), Proceedings the 14th International Coastal Symposium (Sydney, Australia). Journal Research, Special Issue, No. 75, pp. 1247 - 1251. Coconut Creek (Florida), ISSN 0749-0208.The propagation in river as well sediment transport is highly affected by bed beneath wave. Unfortunately, most...

The 2011 tsunami flushed sand spit in front of the Nanakita River mouth, Sendai Coast, Miyagi Prefecture. It also caused severe erosion barrier which is adjacent to left side river mouth. These damages formed concave shoreline at this area after tsunami. morphological recovery presented through analysis aerial photography. time morphology evaluated from analytical solution one-line model. Results indicate that coastal structures both ends have major impact on evolution. Moreover,...

The earthquake and tsunami in 2011 caused serious damages on Sendai Coast, Miyagi Prefecture, Japan. Shoreline change characteristics for periods both before after the are extracted from processing of aerial photographs together with conducting Empirical Orthogonal Function (EOF) analysis. evolution shoreline at Nanakita River mouth Natori areas has been discussed. rates river mouths reveal recovery morphology but different aspect, fast while very slow mouth. results EOF analysis show that...

Aoyama, Y.; Adityawan, M.B., Widiyanto, W., Mitobe, Y., Komori, D., and Tanaka, H., 2016. Numerical Study on Tsunami Propagation into a River. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal Research, Special Issue, No. 75, pp. 1017 - 1021. Coconut Creek (Florida), ISSN 0749-0208.The Tohoku Earthquake in 2011 caused serious damage not only to coastal structures, but also riverine...

2011 Great East Japan Earthquake Tsunami destroyed many coastal dikes located along the Pacific coast in Tohoku Region. From field observations, it is found that most of damages were caused by scouring at a landward toe induced tsunami overflow. Characteristics around discussed through hydraulic experiments. Bed shapes and water levels detected from video images, two types flow patterns observed; jump submerged flow. The strongly affected processes resulting significant differences depths....

蒲生干潟は仙台市東部に位置するラグーンであり,貴重な汽水環境として有用漁業資源生育の面でも貢献していることが明らかになっている.しかし,2011年東日本大震災津波に蒲生干潟は大きな被災を受け,一時,その形状を完全に失った.その後,徐々に以前の地形が回復しつつあり,新たな平衡状態に移行しつつある.そこで,本研究においては被災前から高頻度で撮影されている空中写真の解析を行い,ラグーン地形の被災状況,回復過程,新たな平衡地形に関する検討を行った.その結果,以前の海岸線から比べて後退した位置で汀線は安定しつつあること,また,ラグーン水域の面積は以前に比べて40%程度減少した状態であることなどが判明した.

The Great East Japan Tsunami in March, 2011 caused the significant changes of morphology on Sendai Coast. flushing sand spit front Nanakita River mouth and breaching at Akaiko area can be observed. This study investigates erosion shoreline right side recovery after tsunami. Estimation diffusion coefficient, which is an important parameter numerical simulation change, has been carried out for both areas from measured data erosional propagation. These values coefficient have used to reproduce...

On March 11, 2011, the Great East Japan Earthquake generated huge tsunami waves. Then, propagation occurred and expanded flooded area. Tsunami distance was collected analyzed to estimate area where we need defense. It found in river is about 1.2 4.5 times as long land and, there a good correlation between rivers bed slope. Furthermore, dissipation coefficient of height successfully estimated by applying empirical equation general relation wave distance.

In the 2011 Tohoku Earthquake Tsunami, run-up of tsunami along rivers expanded damaged area into more inland areas far from coast. High water level in was kept for than several times wave period event, while simple periodical oscillations superposed on tidal motion observed 2010 Chile Tsunami event. The difference behaviors discussed with related to magnitude and river mouth morphology through two numerical experiments this paper. first experiments, historical tsunamis simulated Kitakami...

The 2011 tsunami formed concave shoreline around the Nanakita River mouth and Akaiko breaching areas, Sendai Coast, Miyagi Prefecture, Japan. recovery process of morphology in these areas is much depended on longshore sediment which transported from adjacent sandy coasts. Coastal structures both sides portion are considered as rigid boundaries. Analytical solutions one-line model, describe evolution cases without with boundaries, have been discussed. When dimensionless width to length...

Google Earth画像はここ10年程度の期間における汀線変動を知る際にはきわめて有効であり，これまでも多くの海浜変形に関する研究において使用されている．ただし，撮影時刻が示されていないことから，汀線判読にあたって潮位補正を行うことが出来ないという大きな欠点を伴っていた．そこで，晴天時に撮影された画像には建物など背の高い物体の影が写っていることが多いことから，この情報を活用して撮影時刻を推定する手法を提案した．まず，長期にわたり撮影画像が蓄積されている仙台海岸を対象に同手法を適用し，既知の撮影時刻との比較により，推定時刻の誤差が最大でも7分ほどであることを明らかにした．その後にGoogle Earth画像への応用を試み，この補正の有無が中期的な汀線の後退・前進の判断に及ぼす影響を検討した．

2011年東日本大震災津波時に河川を遡上した津波は津波周期を超える長時間にわたって河道内の高水位を維持した．本研究では今次津波による高水位維持のメカニズムについて北上川を対象とした数値実験および歴史津波の再現計算によって検討を行った．2011年津波の入射波高を5~100%まで変化させた仮想津波波形に対する河道内水位変動過程を比較することで，入射津波規模が大きくなると河道内への津波の流入量が流出量に対して相対的に大きくなり，水位が低下しにくい条件へと遷移することがわかった．歴史津波の再現計算結果から今次津波以外の過去の津波においても同様な高水位維持現象が見られた．津波周期は流入量と流出量に対して相関が見られない一方で，入射波高に対して流入量と流出量は明瞭な増加傾向があり，その増加率には有意な差が見られた．