1. 1 TSUNAMI AMANO MAI SEKIYA HIDEHIKO YAMAGUCHI HIROSHI CIVIL ENGINEERING ENGLISH 1 2007/2/6

2. 2 CONTENTS ACCIDENTS CASE 1~3 MECHANISM CAUSES OCCURRENCE TRANSMISSION VELOCITY HEIGHT SUBMERGENCE MITIGATION MEASURES CONCLUSIONS

3. 3 ACCIDENTS ~CASE 1~ FIG. 1 Picture of tsunami 1993/07/12 Okushiri Island was damaged by tsunami. Big earthquake Big tsunami

4. 4 ACCIDENTS ~CASE 2~ Aona port was damaged by tsunami. FIG. 2 Damage of Aona port FIG. 3 Damage of breakwater Fishing boat and the breakwater were destroyed. (http://www.bo-sai.co.jp/sub8.html)

5. 5 ACCIDENTS ~CASE 3~ FIG. 4 Damage of Inaho elementary school Inaho elementary school was damaged by tsunami. TSUNAMI DAMAGE A LOT OF INFRASTRUCTURE!! (http://www.bo-sai.co.jp/sub8.html)

6. 6 MECHANISM ~CAUSES~ The causes of tsunami Earthquakes Volcanic activities Falls of meteors 95 ％ of causes is earthquakes!!!! tsunami is constructed by three parts. 1. OCCURRENCE 2. TRANSMISSON 3. SUBMERGENCE FIG. 5 Sequence of tsunami （ http://ja.wikipedia.org/wiki/%E6%B4%A5%E6%B3%A2 ） http://ja.wikipedia.org/wiki/%E6%B4%A5%E6%B3%A2

7. 7 When earthquake occurs, the bottom of the sea raises or sinks. The reaction from changing crust lifts or pulls down seawater above that point. TSUNAMI OCCURS FIG. 5-a Before tsunami FIG. 5-b After tsunami MECHANISM ~OCCURRENCE~ Mechanism of tsunami

8. 8 1. VELOCITY The velocity of tsunami is only influenced by depth of water. For example VelocityDepth of sea 500m 4000m 252km/h 712km/h This is that of Boeing 707!! 10m36km/h MECHANISM ~TRANSMISSION~ g×d

9. 9 MECHANISM ~TRANSMISSION~ The height of tsunami is influenced by depth of Water. Because depth of shore is low, height becomes too high. 2. HEIGHT Too dangerous!! Maximum of height Japan 38,2m (1896, Meijisanrikutsunami) World 520m (1958, Alaska) FIG. 6 Relationship of tsunami (http://ja.wikipedia.org/wiki/%E6%B4%A5%E6%B3%A2)

10. 10 MECHANISM ~SUBMERGENCE~ FIG. 7-a FIG. 7-b Tsunami is different from tidal wave. Tsunami has potential energy. Potential energy can concentrate in particular topography. Ex) Saw-toothed coastline It's too dangerous!!! Concentration of tsunami

11. 11 MITIGATION MEASURES Actually, there are few provisions. 1.Build a breakwater 2.Live in a concrete building 3.Flee into the second floor if tsunami happens etc. FIG. 8 water gate “byuuo” FIG. 9 Model of “MONE’S HOUSE” (http://www.pref.shizuoka.jp/doboku/buchou1/talk/talk17.htm)(http://www.k3.dion.ne.jp/~monet/sub2zennkei.html)

12. 12 CONCLUSIONS KNOWLEDGE REFUGE RECONSTRUCT