2. By: Febdian Rusydi Aree Witolear
Physics of Tsunami
By:
Febdian Rusydi
Aree Witolear

4. Part 1 Earthquake

5. Causes of Earthquake Volcanic eruption Meteor impacts
Underground explosions (like nuclear tests)
Movement of plates (tectonic)

6. Plate Tectonics Lithosphere  Why does it move?
Comprised of many plates that slide over the lubricating athenosphere layer.
Why does it move?
Fluid (magma) underneath is moving all the time.

7. Plate Tectonics At the boundaries between plates
Plates slide against each other
Plates move apart  magma flows up to the surface
Plates push together  one subducts the other, or neither plate subducts under the other.
San Andreas Fault 2 3 1

8. Earthquake at Sea
1st possibility:

9. Earthquake at Sea
2nd possibility:

11. Part 2 Tsunami

12. Tsunami Tsunami (tsoo – nah – mee)
Tsu (harbor) & nami (wave)
“A natural phenomenon consisting of a series of waves generated when water in a lake or the sea is rapidly displaced on a massive scale” (

13. Theory of Waves Traveling Wave Wave moves energy, not matter!
Energy  E ~ f ~ v/ 
T = 1/f

14. Ocean Waves Wind blows  grab water molecules
Water’s surface stretches  ripples (capillary waves)
Ripples moves  more molecules collected
Size and momentum increase  reach the beach

15. Tsunami Waves

16. “…we only felt that the waves were larger than normal. Only that!”
Tsunami At Sea
Unlike a normal wave, energy of a tsunami moves through the water, not on top of it.
Velocity:
d = water depth
Moves fast in deep waters  400 km/hour!
No more than 1 meter high  can not be seen
“…we only felt that the waves were larger than normal. Only that!”
- Rusli, a fisherman

17. Energy Loss Waves loses energy as it moves away from its source
Energy loss rate ~ 1 / wavelength
 The longer the wavelength, the less energy it loses
Tsunami wavelength = 200 km!
 Energy is almost constant far from epicenter

18. Normal Wave vs Tsunami Wave
Ocean Wave
Speed = kph
Wave Period = 5-20 seconds apart
Wave Length = meters apart
Tsunami Wave
Speed = kph
Wave Period = 10 min-2 hours apart
Wave Length = km apart

19. As Tsunami Moves…

21. At the Beach  v &  decrease, A increase
Shallow water compresses the energy
Tsunami moving away the beach: fast, short height
 v &  increase, A decrease
Tsunami moving toward the beach: slow, tall height
 v &  decrease, A increase

24. Part 3 Impact

25. Some Pictures from Satellite

26. Tsunami 12/26 Magnitude of earthquake = 9.0 SR
Slipped plate length = 1,200 km
Slip over = 15 m
Height of wave reach up to 30 m with speed ~ 800 km/hr

27. Detected Earthquake

28. Tsunami Animation

29. Tsunami in Aceh Magnitude: 9.0 on the Richter scale
The Energy possessed (roughly):
~ 5 MTons of TNT = 2*1018 Joules
~ 2 x explosive energy during all WW II
~ 30% energy consumed in USA a year
~ 70 days Hurricane Isabel

30. Impact on Earth
Some smaller island southwest Sumatera moved ~ 20 m to southwest
Northern tip of Sumatera moved ~ 36m to southwest
Some small islands near Aceh province are gone forever
New lakes/rivers created in ex-land in Aceh, disconnecting transportation to ex-villages

31. What we believe DONATE YOUR MONEY FOR ACEH!
This is not a disaster, but a miracle
Miracle that changes many things in our social life!
The miracle is not finished yet
We have a responsibility, to finish the miracle:
DONATE YOUR MONEY FOR ACEH!

32. Poem by Heri Latief

33. Credits: BBC, How Stuff Works
The End
Credits: BBC, How Stuff Works