Tsunami !

Introductory Oceanography

Ray Rector - Instructor

What is a Tsunami?What is a Tsunami?

What Creates a Tsunami?What Creates a Tsunami?

What Happens When aWhat Happens When aTsunami Approaches Land?Tsunami Approaches Land?

What Happens When a TsunamiWhat Happens When a TsunamiStrikes Population Center?Strikes Population Center?

How Can WeHow Can We PredictPredict,, MonitorMonitor,,WarnWarn,, andand ProtectProtect from Tsunami?from Tsunami?

Tsunami ConceptsTsunami Concepts1) Tsunami are very long wavelength, swift moving, shallow-water ocean waves

2) Tsunami have 100 to 200 km wavelengths, travel at speeds of 600 to 800km/hr, and vary greatly in size

3) Deep open ocean tsunami are only 1 to 3 meter in height, but will drasticallyincrease in wave height along coastlines, due to shelf shoaling

4) Tsunami are triggered by large vertical displacements of water column due toearthquakes, landslides, volcanic eruptions, and bolide impacts

5) Tsunami approaching the shore will appear to look like a massive fast-moving tidal flow cycle – in then out, or out then in.

6) If the trough of a tsunami arrives first, the shoreline will experience anextreme drop in sea level (like an outgoing ultra-low tide) – the crest arrivesas a huge wall of whitewater (like an incoming ultra-high tide)

7) The incredible destructive power of each tsunami wave is two-fold – first, aswave moves landward, and then when it heads back out to sea

8) Tsunami events typically occur as a set of tsunami waves

9) Prediction, monitoring, preparation, and warning of tsunami has been greatlyimproved over the last decade – particularly with DART system.

Tsunami = Harbor WaveTsunami = Harbor Wave

Tsunami = Godzilla Wave?Tsunami = Godzilla Wave?

https://https://www.youtube.com/watch?vwww.youtube.com/watch?v=k8IAgUNr6x4=k8IAgUNr6x4

ゴジラウェーブゴジラウェーブ

The term “tsunami” is Japanese for harbor wave

Tsunami are long wavelength shallow water progressive waves

Typical wavelengths = 50 to 500 km; Average about 100 km

Typical wave periods = 10 to 20 minutes

Tsunami wave speed dependent on water depth:

Typical wave speeds = 500 to 800 km/hr in deep ocean

Open ocean tsunami are difficult to notice at sea = small height

Tsunami often travel as a set of waves

A tsunami drastically changes wave height once it begins toshoal in shallower waters

Tsunami FundamentalsTsunami Fundamentals

Tsunami versus Wind WavesTsunami versus Wind Waves

Origin of TsunamiOrigin of Tsunami

4) Bolide ocean impact

Tsunami can be generated by several means:

1) Seismic event

2) Coastal landslide

3) Volcanic eruption

Formation of Seismic Sea WavesFormation of Seismic Sea Waves A seismic sea wave is generated by arapid vertical displacement of the seabottom during an earthquake

Overlying water column is equallydisplaced, either up or down, dependingon direction of the ruptured seafloor

The influence of gravity on the oceansurface anomaly will cause water columnoscillation resulting in a set of outwardlymoving concentric tsunami waves

Pacific RimPacific Rim –– Tsunami FactoryTsunami Factory

Earthquake-Tsunami ComboThe Deadly One-Two Punch

Recent Tsunami EventsRecent Tsunami Events

December 26, 2004SumatraMaximum wave: 15 mFatalities: >250,000

September 30, 2009SamoaMaximum wave: 7 mFatalities: 170

February 27, 2010ChileMaximum wave: 7 mFatalities: 170

March 27, 1960ChileMaximum wave: 25 mFatalities: 1600

Tsunami ShoalingTsunami Shoaling A tsunami drastically changes its form as a result of “shoaling”

Tsunami ShoalingTsunami Shoaling A tsunami drastically changes its form as a result of “shoaling”

Shoaling: When a tsunami moves out of deep water intoshallower water, the wave will progressively shorten, slow down,and greatly build in wave height

When water depth is 4/3 the wave height the wave will break

The resultant shore-bound tsunami turns into a tremendouslypowerful, swift-moving, wall of turbulent whitewater

In half the instances, the wave trough arrives first – the result isa very unusual drop in sea level (recession of coastal waters)

Tsunami event normally consists of several waves

Shoaling Effects on Tsunami WavesShoaling Effects on Tsunami Waves

Pre-Crest Tsunami Pullout

Video IVideo I –– ThailandThailandhttps://www.youtube.com/watch?v=fTn0UWMXpgo&list=PLkCTP872qR8eWH46LPISlC4GsSZq4cIOW&index=26&feature=iv&src_vid=-5fKvN-RwKs&annotation_id=annotation_3497697433

Tsunami – Coastal Insurge - Flooding

Tsunami – Coastal Insurge - Flooding

Video Footage -- Japan https://www.youtube.com/watch?v=eyxr7nYH96M&list=PLkCTP872qR8eWH46LPISlC4GsSZq4cIOW&feature=iv&src_vid=j0YOXVlPUu4&annotation_id=annotation_1885845763

Post-Tsunami Crest Outsurge -

Video Footage – Japan Offshore Debris

How Can WeHow Can We PredictPredict,, MonitorMonitor,,WarnWarn,, andand ProtectProtect from Tsunami?from Tsunami?

Tsunami Early Warning SystemsTsunami Early Warning SystemsDARTDART -- DDeepeep--oceanocean

AAssessment andssessment andRReporting ofeporting of TTsunamissunamis DART uses sea bottom pressuresensors to sense, track, record,and report open-ocean tsunamiwaves

The DART mooring system is acombination bottom-surfaceinstrument/equipment package

Bottom Instruments includesensitive hydrostatic bottompressure sensor/recorder,transducer, and acoustic release

Surface equipment includes amaster control unit, transducers,RF modem, and antennas

DARTDART -- DDeepeep--oceanocean AAssessmentssessmentandand RReporting ofeporting of TTsunamissunamis

DARTDART -- DDeepeep--oceanocean AAssessmentssessmentandand RReporting ofeporting of TTsunamissunamis

Tsunami Coastal Warning SystemsTsunami Coastal Warning Systems

Coastal warning systems would include offshore and onshore stations

Offshore tsunami and storm surge sensor buoys

Onshore equipment includes data collection and processing stations

Onshore warning systems

How muchHow much Warning TimeWarning Time before abefore aTsunami Hits?Tsunami Hits?

Major generation sites are subduction zones

Tsunami waves travel at 800 km/hr (500 mph)

Tsunami PreparednessTsunami Preparedness

What to do before a tsunami strikes? Know if your area has a tsunami risk

Know the local evacuation route

Be educated about the nature of tsunami

Experiencing a TsunamiExperiencing a Tsunami

What should you doduring a tsunami?

Immediately head to higher ground or inland Warn others as you evacuate the area

Tsunami AftermathTsunami Aftermath

What to do after a tsunami? Stay away from the shorelineuntil ALL the waves have ceased

Seek and/or assist in medicalcare and rescue

CASE STUDY:CASE STUDY: The Great Earthquakeand Tsunami of Japan - March 11, 2011

Great Earthquake and Tsunami of Japan -March 11, 2011

Great Earthquake and Tsunami of Japan -March 11, 2011

Great Earthquake and Tsunami of Japan -March 11, 2011

Animation of Japan Tsunami in Pacific Basin

Great Earthquake and Tsunami ofJapan - March 11, 2011

New York Times – 1) Satellite Photos - Japan Before and AfterTsunami - Interactive Feature - NYTimes.com

2) Map of the Damage From the Japanese Earthquake

NDTV Japan - 1) Earthquake videos2) Japan: Earthquake caught on camera3) Tsunami-hit Japan struggles to reach survivors4) Japan's nuclear crisis worsens5) Japan in Pacific Ring of Fire

JapanEarthquakePictures.com - 1) 2011 Japan EarthquakePictures and Videos

Sumatra Earthquake and TsunamiSumatra Earthquake and TsunamiDec 26, 2004Dec 26, 2004

Sumatra TectonicsSumatra Tectonics

Subduction Model

Faulting Kinematics

Plate Tectonic Map of Sunda Trench-ArcEarthquake Model

Undersea Earthquakes BeneathUndersea Earthquakes Beneaththethe SundraSundra TrenchTrench

Plate Tectonic Map of Sunda Trench-Arc Sunda Subduction Earthquakes

Local ModelLocal Model -- Sumatra TsunamiSumatra Tsunami

Sumatra TsunamiSumatra Tsunami –– 2 Hours2 Hoursafter the Earthquakeafter the Earthquake

Concentric wave pattern

Multiple waves

Wave interaction withregional seafloor topography

Partially tracked by twooverhead satellites

First major tsunami ever tobe tracked by satellite

Global ModelGlobal Model -- Sumatra TsunamiSumatra Tsunami

Tsunami Strikes Phi Phi Island

Tsunami Strikes Koh Phi Phi Island

Video Footage

Banda Aceh, Indonesia Video

Earthquake and Tsunami Footage

Khoa Lak, Thailand Tsunami Video

Patong Beach, Thailand Tsunami Video

Phuket Beach, Thailand Tsunami Video

Impact of Sumatra TsunamiImpact of Sumatra Tsunami

Before

After

ScourScour--Line Along ShorelineLine Along ShorelineNear Banda AcehNear Banda Aceh

Coastal Region near BandaCoastal Region near BandaAceh Totally ScouredAceh Totally Scoured

MeasuringMeasuringRunRun--up nearup nearBanda AcehBanda Aceh

Note the personholding the 6-meterpole for scale

Coastal Region near BandaCoastal Region near BandaAceh Totally LeveledAceh Totally Leveled

Destroyed Coastal Village nearDestroyed Coastal Village nearBanda Aceh CoastBanda Aceh Coast

More Destruction AlongMore Destruction AlongBanda Aceh CoastBanda Aceh Coast

More Destruction AlongMore Destruction AlongBanda Aceh CoastBanda Aceh Coast

More Destruction inMore Destruction inBanda AcehBanda Aceh

Massive Destruction inMassive Destruction inBanda AcehBanda Aceh

More Destruction inMore Destruction inBanda AcehBanda Aceh

CloseClose--up of Destruction inup of Destruction inBanda AcehBanda Aceh

Relief Effort in Aceh Jaya DistrictRelief Effort in Aceh Jaya District

Tsunami ConceptsTsunami Concepts1) Tsunami are very long wavelength, swift moving, shallow-water ocean waves

2) Tsunami have 100 to 200 km wavelengths, travel at speeds of 600 to 800km/hr, and vary greatly in size

3) Deep open ocean tsunami are only 1 to 3 meter in height, but will drasticallyincrease in wave height due to coastal shoaling

4) Tsunami triggered by large vertical displacement of water column due toearthquakes, landslides, volcanic eruptions, and bolide impacts

5) Tsunami approaching the shore will appear to look like a massive fast-moving tidal flow

6) If the trough of a tsunami arrives first, the shoreline will experience anextreme drop in sea level (like an outgoing ultra-low tide) – the crest arrivesas a huge wall of whitewater (like an incoming ultra-high tide)

7) The incredible destructive power of each tsunami wave is two-fold – first, asit moves ashore, and then when it heads back out to sea

8) Tsunami events typically occur as a set of tsunami waves

9) Prediction, monitoring, preparation, and warning of tsunami has been greatlyimproved over the last decade

Discussion

ConclusionConclusion

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