1. Physics of Tsunamis Part 3: Energy of Tsunamis

2. Review from last week  Energy: potential, kinetic, mechanical?  What kind of energy is originally created by displacement of water caused by an earthquake?  Once created, what kind of energy do tsunamis have?  Why is height of the tsunami wave increased in the shallow water?

3. Speed of water waves  In shallow water, bottom of the ocean interfaces with circular motion of the wave causing a friction- like effect and slowing down a wave

4. Check your understanding  Tsunamis are created in the deep ocean, approximately 4km. What is the speed of tsunami wave?  What is the speed of tsunami wave when it reaches shallow water, approximately 90m? 198 m/s ~ 713km/h ~ 445 mph 30 m/s ~ 107 km/h ~ 67 mph

5. Potential energy of tsunami  Displacement of water caused by an earthquake will rise the water above the sea level. The amount of water lifted above the sea level is tied up to gravitational potential energy. E P =mgh [J] m=  h L   - water density: 1000 kg/m 3  - wavelength [m] L h

6. Check your understanding  Determine the energy of the tsunami when it is created.( =150km, L=1200km,h=5m.) E P =8.82 x 10 15 J

7. Group topics  Deadliest Tsunamis in history  Generation of Tsunamis  Creation and propagation of Tsunami waves  Tsunami’s conservation of energy