Class 30: Tides, Waves, Tsunamis, Beaches

Today’s topics:

• Tides

• Wave features

• Beaches & Coastlines

• Tsunamis

Class Updates

• Reading: 16.3-16.4; 16.6-16.8

• Homework #5 posted, due Wed.

4/30

• Final Exam: Mon. May 5th @ 10am

Class 30: Tides, Waves, Tsunamis, Beaches

Ocean Tides - What Causes Them?

Ocean Tides From Gravity

F ~ M / R2

F = forceM = massR = radius

Tidal Pulls: Moon vs. SunWhich exerts a greater pull - Moon or Sun?

Daily Tides from the Moon

Monthly Tides: Moon Phases & Sun

Extreme Tides

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lowtide

high tide

Bay of Fundy (Nova Scotia,

Canada)

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Which statement is most correct about spring tides?

a. They occur in the spring.

b. They occur when the sun, the moon and the Earth all fall on a straight line

c. They are the largest high tides on Earth

d. Both statements b and c are true.

a. Yes, and they would be much LARGER

b. Yes, but they would be much SMALLER

c. No, we would not have tidesd. Maybe, it depends on the season

If Earth didn’t have a moon, would we still have tides?

Sea Waves

1

2

3

4

Circular Motion of Water

Types of WavesQuickTime™ and a

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Sediment Transport Along Coastlines

Beaches

Rocky Coastlines

cliffs

plaforms

Sandy Coastlines

Barrier Islands

Tsunamis

Banda Aceh, Sumatra, Indonesia

December 26, 2004 Magnitude 9.3

TsunamisTsunamis

Underwater fault

1.

BIG earthquake

2.

Tsunami generated

3.

Tsunami Animation

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Tsunami Example: Sumatra

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Tsunami Example: Alaska

Review: Ocean in Motion