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Larry Braile,braile@purdue.edu, web.ics.purdue.edu/~braile

Sheryl Braile

Tsunami! Understanding the Generation, Propagation, and Hazards of Tsunamis

(Despite the popularity of this image, tsunami waves do not normally look like this, especially in the open ocean)

This PowerPoint Presentation (last modified September 30, 2017):http://web.ics.purdue.edu/~braile/edumod/tsunami/Tsunami!.2017.pptx (~28MB)

CSTA Conference, October, 2017, Sacramento, CA

Larry Braile,braile@purdue.edu, web.ics.purdue.edu/~braile

Sheryl Braile

Tsunami! Understanding the Generation, Propagation, and Hazards of Tsunamis

There are several videos in this PowerPoint presentation. If you download the videos (see links on video slides) and put them into the same folder (on your computer) as this PPT (see link on previous slide), the videos will start automatically when you show this PPT presentation. The .avi videos embedded in the PPT will open automatically. If you want to change the video file type, cloudconvert.com (free) works well.

Tsunamis can be generated by:1. Large Earthquakes (megathrust events such

as Sumatra, Dec. 26, 2004; Japan, Mar. 11, 2011)

2. Underwater or near-surface volcanic eruptions (Krakatoa, 1883)

3. Comet or asteroid impacts (evidence for ptsunami deposits from the Chicxulub impact 65 mya)

4. Large landslides that extend into water (Lituya Bay, AK, 1958)

5. Large undersea landslides (evidence for prehistoric undersea landslides in Hawaii and off the east coast of North America)

Schematic plate tectonic setting for tsunami generation

TRENCH

NOAAIn mega-thrust earthquakes, a large area of

the ocean floor is uplifted, and some subsides

Earthquake generation of tsunami(note: tsunami wave in this animation shouldbe asymmetrical with a first peak traveling to the left (in this example) and a first trough traveling to the right)

Animation: add link and video file on next slide to same folder

https://www.youtube.com/watch?v=qQ9Mw_rtDng

m fas this PPT. Go to next slide to start video. Correct explanation is on slide following the video.

http://web.ics.purdue.edu/~braile/edumod/tsunami/generation_small.avi

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Ocean floor dragged down (friction)

Ocean floor bowed up

(elastic bending)

Rebound with fault slip

Peak Trough

Plate Motion

1. Between Earthquakes 2. During Earthquake

Modified (in red) from: http://unesdoc.unesco.org/images/0018/001898/189842e.pdf

Tsunami generation by MegathrustFaulting – note elastic rebound (upper right image), up near fault tip, and down at bowed-up sea floor

3. During the Tsunami

Three measures of tsunami height

1. Wave Height2. Inundation Height 3. Run-up

Height

Run-up height is most often measured in detailed studies a short time after the tsunami. A run-up distance (how far from the coastline the tsunami wave travels) is also commonly measured. All height and distance measurements vary considerably for the same tsunami depending on local variations in coastline shape, near-coastline bathymetry, and topography (on normally dry land) adjacent to the coastline.

The three different measures of reported tsunami height sometimes lead to confusion. For example, for the 2011 Japan tsunami, the wave height has been reported as ~40 m. This measurement was actually a run-up height. Actual wave height was significantly smaller.

Modified (in red) from: http://www.shimz.co.jp/english/theme/earthquake/tsunami.html

Cardboard Foam

Subduction of Plate at Convergent Boundary

Illustrating the positive and negative pulses of the tsunami wave produced by a subduction zone earthquake

Lithosphere bows up here prior to earthquake slip due to elastic bending

Lithosphere dragged down here due to

friction along fault between the upper

and lower plates

Side View

Table Table

http://web.ics.purdue.edu/~braile/edumod/foammod/foammod.htmhttp://web.ics.purdue.edu/~braile/edumod/foammod/foammod.pdf

Foam strips are about 50 cm long, 15 cm wide and 2.5 cm thick. Light-weight poster board is glued to the fault plane surface.

Blind Thrust Fault Earthquake Rupture Animation (Northridge, 1994)Brad Aagaard, USGS

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.htmlThe fault rupture will be visible in the animation. Displacements (magnified 3000

times) will be visible by the movement of the mesh from the model. The amplitude of motions and seismic waves is color coded according to ground velocity.

Note the rupture along the fault over time from the deepest extent of the fault.

http://web.ics.purdue.edu/~braile/new/AagaardBlindThrustAnimation.ppt, http://web.ics.purdue.edu/~braile/edumod/tsunami/BlindThrustSlice.gif

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.html

Earthquake Rupture Blind Thrust Fault Earthquake Rupture Animation – Brad Aagaard, USGS

http://pasadena.wr.usgs.gov/office/baagaard/research/animations/animations.htmlThe fault rupture will be visible in the animation. Displacements (magnified 3000

times) will be visible by the movement of the mesh from the model. The amplitude of seismic waves is color coded according to ground velocity.

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Descriptor Magnitude Average Annually

Great 8 and higher 1 ¹

Major 7 - 7.9 17 ²

Strong 6 - 6.9 134 ²

Moderate 5 - 5.9 1319 ²

Worldwide earthquakes per year (from USGS):

Light 4 - 4.9 13,000 (est.)

Minor 3 - 3.9 130,000 (est.)

Very Minor 2 - 2.9 1,300,000 (est.)

¹ Based on observations since 1900. ² Based on observations since 1990.

Worldwide earthquakes per year:

Frequency-magnitude relationship suggests that magnitude 9+ events will occur about once per decade, statistically; since 1900, the actual number is ~once per 20 years.

Tsunami Statistics (NOAA): http://wcatwc.arh.noaa.gov/tsustats.pdf (Sumatra

Tsunami Statistics

Tsunami Statistics (NOAA): http://wcatwc.arh.noaa.gov/tsustats.pdf

( ) p g p (Dec. 26, 2004 tsunami, over 250,000 deaths; Mar.11, 2011 Japan tsunami, over 18,000 deaths)

Tsunami wave propagation characteristics –note that as water depth becomes smaller, waves slow down, become shorter wavelength (), and have larger amplitude.

When the water is 10 m deep, what is the separation of the waves in minutes? (hint: t = v)

NOAA

Water waves animationDirection of propagation

Animation courtesy of Dr. Dan Russell, Kettering University (now at Penn State; http://www.acs.psu.edu/drussell/demos.html)

Tsunami velocity and amplitude equations(These are plane layer [flat ocean bottom] equations)

1. Wave velocity controlled by water depth:

v = (g x d)1/2 where v is velocity, d is water depth and g is the acceleration of gravity = 9.8 m/s2; so, velocity decreases in shallower water(http://www.tulane.edu/~sanelson/Natural_Disasters/tsunami.htm,https://www.youtube.com/watch?v=8SXsgcnNWUM – model wave tank)

2. Wave height (amplitude) increases (conservation of energy) in shallow water:AS = AD x (VD/VS)1/2 where AS = amplitude in shallow water, AD = amplitude in deep water, VS= velocity in shallow water, and VD = velocity in deep water.

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Wave Heights – Satellite observation versus calculated model – open ocean, deep water

Geist, Titov and Synolakis, Tsunami: Wave of Change, Scientific American, January, 2006.

~1600 km; ~2.2 hours of waves at 750 km/hr

Waves spread out in circular pattern and the amplitudes become smaller with time (conservation of energy), also note dispersion (longer wavelengths travel faster) http://web.ics.purdue.edu/~braile/edumod/tsunami/sept2009_87.short.5.wmv

Large wave tank using a plastic storage container. Distances in are marked on the bottom of the container for measurement of wave velocity from the distance and travel time. Small floating flags are useful for identifying the time and relative amplitude of propagating water waves. In this sequence of photos, one can see the waves propagating outward from the source (a ping pong ball dropped into the water). B. (~ 0.5 s after the source) Water waves have propagated from the source to about 10 cm p p gdistance. A circular expanding wavefront is visible and the wave height is larger than in the later photos. C. (~ 1.0 s) The wavefronthas propagated to about 20 cm distance and the waves have decreased in amplitude. D. (~ 1.5 s) The wavefront has propagated to about 30 cm distance. Because the waves traveled about 40 cm in 2 seconds, the velocity of propagation is about 20 cm/s or 0.2 m/s. (Also see: http://web.ics.purdue.edu/~braile/edumod/slinky/slinky.htm.)

Tsunami Wave Tank (2014 images and videos)1. “SnapLock Select” plastic underbed storage box

118 x 51 x 13 cm (45” x 21” 5”) from Walmart, K-Mart, etc.(or Sterilite #1996, 74 qt.), remove handles, fill holes with silicon sealer.

2. Plexiglass53 x 48 x 0.5 cm (21” x 19” x 3/16”) [could use[could use sand for “coastalarea” instead ofplexiglass].

3. Two 30 cm plasticrulers with claybase, 30 cm apart.

4. Fill to 8 cm deepwith water.

Tsunami Wave Tank Tsunami Wave Tank (close-up of ruler and plexiglass –note slope representing shallowing of water depth adjacent to coast)

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Tsunami Wave Tank – Video of Wave TankDownload Tank.mov from:

http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm

Tsunami Wave Tank – Video of WavesWater Drop – Point source, circular spreading of energy:Download WaterDrop3.mov and WaterDrop4Measure.mov from:

http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm

1. What are the characteristics of the wavesgenerated by the water drop?2 Measure the velocity of the2. Measure the velocity of the wave using a stopwatch (distance from center to side of tank in cm, divided by timein seconds).3. Can you observe reflectedwaves.4. Why do the waves eventually disappear?

Tsunami Wave Tank – Video of WavesLine Source (plane wave) – No spreading of energy:

Download PlaneWave1.mov from:http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm 1. What are the characteristics of the wavesgenerated by the line source?2. Measure the velocity of the wave using a stopwatch (follow one wave crest from firstruler to the second – 30 cm divided by time).3. What is the wave height?4. What is the wave length?5. Do the waves get smallerwith distance of propagation?6. What type of water wave inthe ocean is similar to thesewaves?

Ocean Waves

Tsunami Wave Tank – Video of WavesTsunami – Line source and entire water column disturbed:

Download Tsunami2.mov from:http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm 1. What are the characteristics of the waves generated by the tsunami source?2. Measure the velocity of the wave using single frame advancewave using single frame advance (follow one wave crest from firstruler to the second – 30 cm divided by time).3. What is the wave height?4. What is the wave length?5. What happens to the wave as it propagates into shallow water?

Tsunami Wave Tank – Video of WavesTsunami – Line source and entire water column disturbed:

Download Tsunami4Measure.mov from:http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm

(Use pause and single frame advance to observe wave characteristics)

~5.8 s ~6.2 s

Note Long Wavelength Note Wave Cresting

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Tsunami Wave Tank MaterialsWave generation sources; drop into water or oscillate up and down

on water surface to create waves: Golf ball, plastic golf ball (or table tennis ball), eye dropper, clay, wood, styrofoam strips

48 x 10 x 2.5 cm(19” x 3.75” x 1”)

Tsunami Wave Tsunami Wave Tank (2017 images and videos)

From point source, waves spread out in all directions and lose energy quickly.

http://web.ics.purdue.edu/~braile/edumod/tsunami/BallDrop.avi

For a plane wave source, wave does not spread out so it loses energy slowly.

http://web.ics.purdue.edu/~braile/edumod/tsunami/PlaneWave.avi

Multiple plane waves simulate wind-generated waves from a distant storm system creating wave action on the coastline that we often call surf.http://web.ics.purdue.edu/~braile/edumod/tsunami/Surf.avi

The tsunami wave is created by large volumes water being disturbed by sudden movements of the ocean bottom by faulting. Notice that the waves “bounce around” in our model ocean basin – of course our ocean basin is quite small, but the same effect is seen in Earth’s oceans.http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiWave.avi

Maximum wave height at first ruler ~ 1.0 cm; Wave height at second ruler ~ 1.5 cm. The wave height has increased in the shallow water because the waves travel slower and the energy is almost the same so the wave amplitude increases (conservation of energy).http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiMeasure.avi

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Single plane wave impacting coastline with model clay buildings.

http://web.ics.purdue.edu/~braile/edumod/tsunami/PlaneWaveBuildings.avi

Multiple plane waves impacting coastline with model clay buildings; notice surf effect including breaking waves in the shallow water.http://web.ics.purdue.edu/~braile/edumod/tsunami/SurfBuildings.avi

Tsunami waves impacting coastline with model clay buildings. Waves inundate the beach area and the base of the buildings.

http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiBuildings.avi https://www.youtube.com/watch?v=tc-x3ELeYhs

26 Dec. 2004 Tsunami max. wave height and arrival time

Geist, Titov and Synolakis, Tsunami: Wave of Change, Scientific American, January, 2006.

Seismic Eruption (SeisVolE) software: https://www.binghamton.edu/geology/people/faculty/jones.htmlIndonesia area historical earthquakes files, download from:http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm

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Seismic Eruption (SeisVolE) software: https://www.binghamton.edu/geology/people/faculty/jones.htmlIndonesia area historical earthquakes files, download from:http://web.ics.purdue.edu/~braile/edumod/tsunami/TsunamiFiles.htm

Tsunami simulation(Note: wave trough is first arriving energy propagating to th E t d the East, and focusing of energy to west and east of the earthquake rupture area)

http://staff.aist.go.jp/kenji.satake/animation.gif

Chedi Resort,Phuket, Thailand, wave height ~4+ m (?, from estimates of water level from beach umbrellas on grassy area above the beach)

Teaching about natural hazards (earthquakes, tsunamis, hurricanes, tornadoes, etc., where there is “death and destruction”)Fear factor

An excellent positive and moving story about the Japan tsunami is “The Extraordinary Voyage of Kamome – A Tsunami Boat Comes Home” by Lori Dengler and others, (2015) Humboldt State University ***(can be purchased from amazon.com or downloaded for free (full pdf) from http://digitalcommons humboldt edu/monographs/1/)***http://digitalcommons.humboldt.edu/monographs/1/)

Note risk factors, locations and probabilities

How to stay safe

Importance of understanding of Earth processes

Tsunami concepts are not likely to be included on typical state standardized tests, but the concepts (causes, generation and propagation of tsunami, probabilities and risk assessment, etc.) are good exercises in science and critical thinking.

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Tilly Smith and the Dec. 26, 2004 Sumatra tsunami, Phuket, Thailand (about 10,000 people were killed by the tsunami in Thailand). Tilly is credited with saving the lives of about 100 people because she recognized the warning signs of an oncoming tsunami.“Tilly Smith learned about tsunamis in a geography lesson two weeks before the tsunami from her teacher Andrew Kearney at Danes Hill School in Oxshott, Surrey. She recognised the symptoms of receding water from the shoreline and frothing bubbles on

http://en.wikipedia.org/wiki/Tilly_Smith

http://news.nationalgeographic.com/news/2005/01/0118_050118_tsunami_geography_lesson.html

https://www.youtube.com/watch?v=6C3CJX1-d_8&spfreload=10

http://nalakagunawardene.com/2007/10/10/geography-lesson-that-saved-many-lives-the-story-of-tilly-smith/

recognised the symptoms of receding water from the shoreline and frothing bubbles on the surface of the sea and alerted her parents, who warned others on the beach and the staff at the hotel on Phuket, where they were staying. The beach was evacuated before the tsunami reached shore, and was one of the few beaches on the island with no reported casualties.” (http://en.wikipedia.org/wiki/Tilly_Smith)

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Banda Aceh, Sumatra, before tsunamihttp://geo-world.org/tsunami/

Banda Aceh, Sumatra, after tsunamiAlso: http://www.digitalglobe.com/

Up to 10 m high tsunami waves hit coastal area near Up to 10 m high tsunami waves hit coastal area near Sendai, in northern Honshu, JapanSendai, in northern Honshu, Japan

Tohoku, Japan tsunami, March 11, 2011

Tohoku, Japan Earthquake: Aftershock (and Foreshock) Sequence, 03/08/11 - 03/16/11

Note that the magnitudes of the 2011/03/11 06:15 (Mw 7.9) and 2011/03/11 06:25 (Mw 7.7) aftershocks were updated from earlier, lower estimates. Updates occurred on 03/16 and 03/18, respectively.

Maximum wave amplitudes – 2011 Japan tsunami. (http://www.noaa.gov/features/03_protecting/images/Energy_plot_japantsunami.png - note) significant directivity in the wave energy. Wave height and velocity can also be greatly affected by shape of the coastline and details of ocean bottom bathymetry in coastal shallow waters.

Kahului, Maui Tide data, March 8 – March 10, 2011 GMT

Predicted Observed

(http://tidesandcurrents.noaa.gov/index.shtml, http://tidesandcurrents.noaa.gov/station_retrieve.shtml?type=Tide+Data)

Difference

Max. Amplitude ~ 0.3 meters

Tides

24 hr

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Kahului, Maui Tide data, March 11, 2011 GMT

Ob d

Tsunami (+/- 2 m waves, ~ 30 minute period)

PredictedObserved

Difference

Max. Amplitude ~ 2.0 meters

8 hr

Kahului, Maui Tide data, February 18 - March 20, 2011 GMT

Predicted Observed

Tsunami (still propagating through Pacific Ocean 7 days later)

Tides

DifferenceMax. Amplitude ~ 2.0 meters

10 days

Tsunami Near Sendai Airport

Tsunami Damage Near Sendai

Tsunami Damage from the Tohoku [Northern Honshu, Japan] M9.0 Earthquake of March 11 – Satellite View before Tsunamihttp://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html

Tsunami Damage from the Tohoku [Northern Honshu, Japan] M9.0 Earthquake of March 11 – Satellite View after Tsunamihttp://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html

Tsunami Damage from the Tohoku [Northern Honshu, Japan] M9.0 Earthquake of March 11 – Satellite View before Tsunamihttp://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html

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Tsunami Damage from the Tohoku [Northern Honshu, Japan] M9.0 Earthquake of March 11 – Satellite View after Tsunamihttp://www.nytimes.com/interactive/2011/03/13/world/asia/satellite-photos-japan-before-and-after-tsunami.html

Some other recent tsunamis that have impacted the western U.S.

1946 Aleutian Islands earthquake (M8.6)

Tsunami wave heights and fatalities: Oregon and California –Coo’s Bay (~3 m), Ft. Bragg (~2-3 m), Half Moon Bay (~3-4 m), Muir Beach (~4 m), Santa Cruz (~3 m, one death). Hawaiian Islands – (6-7 waves, ~15 minute period, ~8-16 m, 159 deaths, mostly in Hilo)., y )

1964 Aleutian Islands earthquake (M9.2)

Tsunami wave heights and fatalities: Seaside, Oregon (3-4 m, 4 deaths; Crescent City, California (6 m), 10 deaths (total of 12 deaths in California).

http://www.usc.edu/dept/tsunamis/alaska/1946/webpages/index.htmlhttp://www.usc.edu/dept/tsunamis/alaska/1964/webpages/index.html

M9.2 1964 Alaska earthquake

Largest Waves

http://www.usc.edu/dept/tsunamis/alaska/1946/webpages/http://www.aeic.alaska.edu/quakes/Alaska_1964_earthquake.html, Revisions in red.

M8.6 1946 Aleutians earthquake

Other sources of tsunamis for western U.S.

The Cascadia subduction zone is likely the source area for a tsunami that struck Japan in the year 1700.

Comparison of the size of the aftershock zone for the 2004 Sumatra

http://en.wikipedia.org/wiki/1700_Cascadia_earthquake

Evidence for Cascadia tsunami: The Orphan Tsunami of 1700(published 2005, Brian Atwater and others)

aftershock zone for the 2004 Sumatra earthquake with the Cascadiasubduction zone

http://en.wikipedia.org/wiki/1700_Cascadia_earthquake

Tsunami simulation for megathrustearthquake in Cascadia impacting Japan, and other locations on the Pacific ocean basin (http://pubs.usgs.gov/pp/pp1707).

“A simulated tsunami reaches Japan ten hours after its start along the Pacific coast of North America” (http://pubs.usgs.gov/pp/pp1707).

http://pubs.usgs.gov/pp/pp1707/pp1707.pdf

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Earthquake and Tsunami Safety• Earthquake safety – “Duck and cover”.

• Tsunami safety (when in a coastal, near-sea-level area; two situations: local EQ or distant EQ):

• If you feel strong shaking for 15+ seconds; after shaking, move to higher ground.

If h i i i if b• If there is a tsunami warning, or if you observe unusual waves (appear to be large and rapid tidal changes, or water recedes), move to higher ground.

• Do not return until event is over; a tsunami includes multiple waves sometimes separated

by 10-30 minutes and may last for hours.

Tsunami Teacher Resources (ITIC)

Tsunami Teacher Resource Kit (17 MB pdf) from ITIC (International Tsunami Information Centre) http://www.tsunamiwave.info/

Tsunami Basics (ITIC): https://www.youtube.com/watch?v=tUN_UTY0GNo&list=PL3BDBAAAA7D4EB2DA&index=11

IRIS Posters: http://www.iris.edu/about/publications.htm#p

Tsunami Videos:Tsunami wave spills over seawall, smashes boats, cars http://www.youtube.com/watch?v=5-zfCBCq-8I&feature=player_embedded#at=22

Massive Quake Triggers Tsunami in Japanhttp://www.youtube.com/watch?v=1XpSLiPHLPk&feature=player_embedded

Japan Earthquake 3.11.2011 - Tsunami hits http://www.youtube.com/watch?v=s8L2kikyVzk&feature=player_embedded

TSUNAMI SENDAI AIRPORT (JAPAN 3/11/11) http://www.youtube.com/watch?v=k6agTZo3E5Y&feature=related

First tsunami waves hit Hawaii islands, California coast after Japan 2011 earthquake http://www.youtube.com/watch?v=FEeHkr5ew3c&feature=related

Crescent City CA March 11 2011 Tsunami Time Lapse videoh // b / h? i6 Pk0VHDYhttp://www.youtube.com/watch?v=ai6pPk0VHDY

Crescent City Takes Tsunami Toll http://www.youtube.com/watch?v=SPqCX1FUdU0

Tsunami rocks boats in Santa Cruz harborhttp://www.youtube.com/watch?v=cswolureeF4

Wall of Water Slams Japanese Townhttp://news.yahoo.com/video/world-15749633/wall-of-water-slams-japanese-town-24518186

Kailua Kona Tsunami Time Lapse 2011 Bay Fronthttp://www.youtube.com/watch?v=YjCV182S5y4&feature=player_embedded

Japanese Earthquake Tsunami Wave arrives in Emeryville CAhttp://www.youtube.com/watch?v=jdMDCLwblkY&feature=player_embedded

https://www.youtube.com/watch?v=k3_m3lACJOo 2004

Larry Braile,braile@purdue.edu, web.ics.purdue.edu/~braile

Sheryl Braile

Tsunami! Understanding the Generation, Propagation, and Hazards of Tsunamis

(Despite the popularity of this image, tsunami waves do not normally look like this, especially in the open ocean)

This PowerPoint Presentation (last modified September 30, 2017):http://web.ics.purdue.edu/~braile/edumod/tsunami/Tsunami!.2017.pptx (~28MB)

2014 PowerPoint Presentation (last modified December, 2014):http://web.ics.purdue.edu/~braile/edumod/tsunami/Tsunami!.ppt