Tsunami

Tsunami

Tsunami is Japanese for “harbor wave”

Caused by the vertical displacement of ocean water

Triggered by:Large earthquakes that move the sea floorUnderwater landslidesVolcano flank collapseSubmarine volcanic explosionAsteroids

Another category: Mega tsunami

Tsunami

11 major tsunamis since 1990 over 200,000 lives lost

Ways to create a tsunami

Subduction-zoneearthquake

larger thanM 7-7.5

100 years laterstored tension

Fault rupture

Response after earthquake

0 minutes

10 minutes

20 minutes

Figure 3.6

Rupture on seafloorproduces seismic wave

Wave moves rapidlyacross ocean (400 mph)

Wave slows (25 mph)and steepens near shore

Uprush of waveinundates and destroys coastal zone

Okushiri, Japan

Wave animations

Wave animations

Okushiri, Japan

Sumatra & the Java Trench

USGS

Indonesian tsunami 2004

Initial earthquakeand after shocks

Tsunami path through the ocean

Detected by tide gauges

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Southern Indian Ocean

MaldivesSeychelles

Meulaboh,Indonesia

Meulaboh, Indonesia

Meulaboh, Indonesia

Scale of a tsunami

Banda Aceh, Indonesia

Fig. 10-32b, p. 289

Banda Aceh, Indonesia

Figure 3.12b

Meulaboh, Indonesia

Fig. 10-32c, p. 289

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Kata Noi receding wave

Water receding from shoreline

Water receding from shoreline

Ways to create a tsunami

Submarinelandslideon edge ofslope

Submarine landslide

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Oregon continental slope

6 kmwide

Simulation of landslide-induced wave

Papua New Guinea

Papua New Guinea

July 17, 19982100 deaths

tsunami waves 30 feet high

landslide of 1 cubic mile of sediment

triggered by a magnitude 7.0earthquake

Coastal villageBefore: After:

TsunamiTsunamiTsunamiWays to create a tsunamiResponse after earthquakeOkushiri, JapanWave animationsWave animationsOkushiri, JapanSumatra & the Java TrenchUSGSTsunami path through the oceanDetected by tide gaugesSouthern Indian OceanMeulaboh, IndonesiaMeulaboh, IndonesiaMeulaboh, IndonesiaScale of a tsunamiBanda Aceh, IndonesiaFigure 3.12bMeulaboh, IndonesiaKata Noi receding waveWater receding from shorelineWater receding from shorelineWays to create a tsunamiSubmarine landslideSimulation of landslide-induced wavePapua New GuineaPapua New GuineaCoastal villageHilo Bay, HawaiiHawaii 1947Hawaii 1947Hawaii 1947Hawaii 1947Major tsunamis in AlaskaAlaska 1964Lituya Bay, AlaskaLituya Bay, AlaskaLituya Bay, AlaskaLituya Bay, AlaskaLituya Bay, AlaskaKrakatau 1883Forming a caldera – Crater Lake, OregonForming a calderaCinder cone with a collapsed craterNorth Atlantic OceanTenerife,Canary IslandsOrotova landslideAlika submarine landslideAlika submarine landslideDropAsteroid impactMega tsunamiMega tsunamiMinimizing the Tsunami HazardTsunami Warning SystemFigure 3.13aTsunami run-up mapWhat Individuals Can DoMinimizing the Tsunami Hazard, cont.Minimizing the Tsunami Hazard, cont.