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The quake moved portions of northeastern Japan by as much
as 2.4 m (7.9 ft) closer to North America, making portions of
Japan's landmass wider than before. Portions of Japan
closest to the epicenter experienced the largest shifts.]A 400
km (250 mi) stretch of coastline dropped vertically by 0.6 m
(2.0 ft), allowing the tsunami to travel farther and faster onto
land One early estimate suggested that the Pacific plate may
have moved westward by up to 20 m (66 ft and another early
estimate put the amount of slippage at as much as 40 m (130 ft)](https://image.slidesharecdn.com/anshumeshx-a46-copy-130713000916-phpapp01/75/THE-BEST-TSUNAMI-PRESENTATION-17-2048.jpg)
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THE BEST TSUNAMI PRESENTATION
A tsunami is a series of waves generated by large displacements of water, typically caused by earthquakes, volcanic eruptions, landslides, or meteorite impacts under water or along coastlines. Common triggers include large earthquakes, volcanic eruptions, and landslides. When a major earthquake or landslide occurs near or undersea, it can displace enough water to cause a destructive tsunami. Coastal areas are most at risk from tsunamis, as the waves travel inland rapidly.
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THE BEST TSUNAMI PRESENTATION
- 1.
- 2. 2 A tsunami isa series of water waves caused by the displace- ment of a largevolume of a body of water, generally an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impa- cts andother disturbances above or below water all have the potential to generate a tsunami.
- 3. 33 • EarthquakesEarthquakes • VolcanoesVolcanoes •LandslidesLandslides • AsteroidsAsteroids • can allcan all triggertrigger
- 4. 4 • These arethe most destructive and common tsunamis; • When a quake is colossal, at least 7.5 in magnitude, it displaces enough water to case a huge wave; • Such quakes often occurs at a thrust fault. cause Tsunamis! Past Earthquakes and Tsunamis in the Indian Ocean– note the magnitude of the 1883 and 2004 earthquakes/tsunamis
- 5. 5 (1) A classic aboveground eruption can disturbthe ocean floor and generate a tsunami. can cause tsunamis!
- 6. 6 - contd. (2) submarineevents like eruptions, cascades of ash or the collapse of a volcanic flank, can also be the cause of a tsunami. In 1883, the volcanic eruption of Krakatau and the collapse of its caldera stirred up 130-foot high waves and killed 36,000 people.
- 7. 7 Usually set offby •Earthquakes or •Rock and icefalls Highest such wave was recorded in Lituya Bay, Alaska in 1958: a quake- triggered rock fall threw up a 500+m wave. can cause tsunamis!
- 8. 8 At particular riskare those places which are found at the juncture of tectonic plates
- 9. 9 A seawall atTsu, Japan Tsunamis, like most natural disasters, are beyond human control. There are, however , a number of techniques that can minimize the harmful effects of tsunamis to the physical environment (including built structures) and to individuals and communities. Accompanied by an effe- Ctive warning system, thoughtful design and strong community organization can reduce harm fromTsunamis and other natural disasters. Mitigation and preve- ntion through: site strategies | community development | ecology
- 10. 10 The US NationalTsunami Hazard Mitigation Program’s publication Designing for Tsunamis stresses the importance of unde- rstanding site conditions. Through zoning, creation of open space and not allowing new development in potential tsunami areas, safer land use will be better able to protect people and buildings. In redevelopment of high risk areas four basic site planning techniques need to be consi- dered. Please refer to page 4-11, Table 4-1. Mitigation Methods for Selected Types of Development which gives a variety of building solutions based on the four basic site planning techniques listed below.
- 11. 11 Avoid Inundation Areas:Site Buildings or infrastructure away from hazard a or locate on a high point. low Water: Forests, ditches, slopes, or berms can slow down waves and er out debris. The success of this method depends on correctly estimating the ce of the tsunami. teering: Water can be steered to strategically placed angled walls, ditches d paved roads. Theoretically, porous dikes can reduce the impact of violent ves. Blocking : Walls, hardened terraces, berms and parking structures can be lt to block waves.he house and household in a wide community context such whether it is a majority or minority situation, the conflict situation and own- hip issues.
- 12.
- 13. 13 The 2011 earthquakeoff the Pacific coast of Tōhoku often referred to in Japan as the Great East Japan Earthquake and also known as the 2011 Tohoku earthquake and the 3.11 Earthquake, was a magnitude 9.0 (Mw) undersea meg- athrust earthquake off the coast of Japan that occurred at 14:46 JST (05:46 UTC) on 11 March 2011, with the epicentre approximately 70 kilometres (43 mi) east of the Oshika Peninsula of Tōhoku and the hypocenter at an underwater depth of approximately 30 km (19 mi). It was the most powerful known earthquake ever to have hit Japan, and the fifth most powerful earthquake in the world since modern record-keeping began in 1900. The earthquake triggered powerful tsunami waves that reached heights of up to 40.5 metres (133 ft) in Miyako in Tōhoku's Iwate Prefecture and which, in the Sendai area, travelled up to 10 km (6 mi) inland.
- 14. 14 The tsunami causednuclear accidents, primarily the level 7 meltdowns at three reactors in the Fukushima Daiichi Nuclear Power Plant complex and the associated evacuation zones affecting hundreds of thousands of residents. Many electrical generators were taken down, and at least three nuclear reactors suffered explosions due to hydrogen gas that had built up within their outer containment buildings after cooling system failure. Residents within a 20 km (12 mi) radius of the Fukushima Daiichi Nuclear Power Plant and a 10 km (6.2 mi) radius of the Fukushima Daini Nuclear Power Plant were evac- Uated. . In addition, the U.S. recommended that its citizens evacuate up to 80 km (50 mi) of the plant.
- 15. 15 This earthquake occurredwhere the Pacific Plate is subducting under the plate beneath northern Honshu; which plate is a matter of debate amongst scientists The Pacific plate, which moves at a rate of 8 to 9 cm (3.1 to 3.5 in) per year, dips under Honshu's underlying plate releasing large amounts of energy. This motion pulls the upper plate down until the stress builds up enough to cause a seismic event. The break caused the sea floor to rise by several meters. A quake of this magnitude usually has a rupture length of at least 480 km (300 mi) and generally requires a long, relatively straight fault surface.
- 16. 16 his earthquake releaseda surface energy (Me) of 1.9 ± 0.5× 17joules,dissipated as shaking and tsunamic energy, which 18 double that of the 9.1-magnitude 2004 Indian Ocean rthquake and tsunami that killed 230,000 people . harnessed, the surface energy from this arthquake would power a city the size of Los Angeles for an ntire year. The total energy released, also known as the eismic moment (M0), was more than 200,000 times the urface energy and was calculated by the USGS at 3.9×1022 oules.
- 17. 17 The quake movedportions of northeastern Japan by as much as 2.4 m (7.9 ft) closer to North America, making portions of Japan's landmass wider than before. Portions of Japan closest to the epicenter experienced the largest shifts.]A 400 km (250 mi) stretch of coastline dropped vertically by 0.6 m (2.0 ft), allowing the tsunami to travel farther and faster onto land One early estimate suggested that the Pacific plate may have moved westward by up to 20 m (66 ft and another early estimate put the amount of slippage at as much as 40 m (130 ft)
- 18. 18 Japan experienced over1000 aftershocks since the earthquake, with 80 registering over magnitude 6.0 Mw and three of which were over magnitude 7.0 Mw. A magnitude 7.7 Mw and a 7.9 Mw quake occurred on 11 March and the third one struck offshore on 7 April with a disputed magnitude. Its epicenter was underwater, 66 km (41 mi) off the coast of Sendai. The Japan Meteorological Agency assigned a magnitude of 7.4 MJMA, while the U.S. Geological Survey lowered it to 7.1 Mw.
- 19. 19 The tsunami issuedby the Japan Meteorological Agency was the most serious on its warning scale; it rated as a "major tsunami", being at least 3 m (9.8 ft) high. . The actual height prediction varied, the greatest being for Miyagi at 6 m (20 ft) high. The tsunami inundated a total area of approxima- tely 561 km2 (217 sq mi) in Japan.
- 20. 20 The National PoliceAgency has confirmed 15,883 deaths, 6,145 injured,and 2,671 people missing across twenty pref- ectures.Of the 13,135 fatalitiesrecovered by 11 April 2011, 12,143 or 92.5% died by drowning. Victims aged 60 or older accounted for 65.2% of the deaths, with 24% of total victims being in their 70s. As of March 2012, Japanese police data showed that 70% of the 3,279 still missing were aged 60 or over, including 893 in their 70s and 577 in their 80s. Of the total confirmed victims, 14,308 drowned, 667 were crushed to death or died from internal injuries, and 145 perished from burns.
- 21. 21 From 14 to17 June 2013, Indian state of Uttarakhandand adjoining area received heavy rainfall, which was about 375 percent more than the benchmark rainfallduring a normal monsoon. This caused the melting of Chorabari Glacier at theheight of 3800metres, and eruption of the Mandakini River whichled to heavy floods near Kedar Dome, Rudrapr -ayag district, Uttarakhand .
- 22. 22 Landslides, due tothe floods, damaged severa houses and structures, killing those who were trapped.The heavy rains resulted in large flas- hfloods and massive landslides. Entire villag- es and settlements such as Gaurikund and the market town of Ram Bada, a transition point to Kedarnath, have been obliterated, while the market town of Sonprayag suffered heavy heavy damage and loss of lives. Pilgrimage centres in the region, including Gangotri, Yamunotri, Kedarnath and Badrinath, the hallowed Hindu Chardham (four sites) pilgrimage centers, are visited by thousands of devotees, especially after the month of May onwards. Over 70,000 people were stuck in various regions because of damaged or blocked roads. People in other important locations like the Valley of flowers, Roopkund and the Sikh pilgrimage centre Hemkund were stranded for more than three days.
- 23. 23 Although the KedarnathTemple itself had not been damaged, its base was inundated with water, mud and boulders from the landslide, damaging its perimeter. Many hotels, rest houses and shops around the temple in Kedarnath township were destroyed, resulting in several casualties. Most of the destruction at Kedarnath was caused by a sudden rapid melting of ice and snow on the Kedarnath Mountain, 6 km (3.7 mi) from the temple, which flooded the Charbari lake (upstream) and then Kedarnath. Temple was flooded with water resulting in several deaths due to drowning and panic-driven stampede. The Uttarakhand Govern- ment announced that due to the extensive damage to the infrastructure, the temple will be temporarily closed to regular pilgrims and tourists for a year or two, but the temple rituals will still be maintained by priests. Even after a week, dead bodies were not lifted from Kedarnath town, resu- lting in contamination of water in Kedarnath valley.
- 24.
Editor's Notes
- #5 A thrust fault is a fault where an ocean plate dives under a continental plate, dragging it down until the fault snaps, causing an earthquake that lifts the seafloor.