waves and tides

1. PRESENTED BY UNDER GUIDANCE OF
PRAMODA G DR. BALASUBRAMANIAN A
1ST
SEMESTER, PROFESSOR
APPLIED GEOLOGY
Presentation on
OCEAN WAVES AND
TIDES

2. CONTENTS
• Introduction
• Waves
• Types of waves
• Tsunamis
• Tides
• Types of tides
• Importance of tides
• Conclusion
• Reference

3. INTRODUCTION
• A wave is any disturbance created when energy
moves through an object or substance.
• There are many types of waves caused by different
forces – some examples are earthquakes, ocean
waves, radio waves, visible light waves, and
atmospheric waves.
• Tide, alternate and regular rise and fall of sea level in
oceans and other large bodies of water.
• These changes are caused by the gravitational
attraction of the moon and, to a lesser extent, of the
sun on the earth.

4. •
A disturbance on the surface
of water, caused by the
rhythmic movement of
water particles due to the
action of winds.
•
The height of the wave
depends on the speed of the
wind.
•
A tsunami is a very long
wave caused by submarine
or coastal earthquakes,
landslide or volcanic
eruption.
WAVES

5. WAVE
CHARACTERISTICS
Parts of a Wave

Crest = high point

Trough = low point

Height = vertical distance
a from crest to trough

Wavelength = Horizontal
distance between crest to
crest or trough to trough

6. Wave period : time
for 2 crests to pass
fixed point (T) sec
Wave speed (C) : C =
wavelength / T (m/s)
Wave steepness : H /
wavelength
When H /
wavelength = 1/7 or
angle at crest 120 or
less = Breaker

7. SIZE OF WIND GENERATED WAVES
 Depends on 3 things:

Wind Speed

Wind Duration
(length of time wind
blows)

“Fetch” Extent of
open water across
which the wind can
blow

8. WATER MOTION IN WAVES
 Water travels in
vertical circular
orbits
 Wave moves,
particles don’t!

9. TYPES OF WAVES

10. Tsunami Waves
Caused by undersea quake
or volcano
Wavelength = ~150 mi.
Wave height = 6” – 1’
Can NOT perceive in boat
Speed > 500 mph
lows down to ~25 mph at
shore; water builds up to
~65+ ft
A tsunami also known as a seismic sea wave, is a series of
waves in a water body caused by the displacement of a large
volume of water, generally in an ocean or a large lake.

12. IMPORTANCE OF WAVES
 Shaping Coastlines

Erode cliffs

Grind rock into sand
 Ecology
 Returns O2
to water

Stir up food for filter
feeders

13. TIDES

14. • Are the alternate rise and fall in the level of sea
water, caused by the combined effects of the
gravitational forces exerted by the Moon and the
Sun and the rotation of the Earth.

15. • High Tide is when the level of sea water rises, and
moves up the shore.
• Low tide is when the level of sea water falls and
water recedes from the shore.
• Most coastal areas experience two high and two low
tides per day.

17. • Is caused when the pulls
of the moon and sun act
on the same line during
full moon and new
moon
• High tides are higher
than usual and low tides
lower

18. • Is caused when the moon is in
the first or third quarter,when
the moon,sun and earth form
a right angle
• The height of the tide
produced by the moon's
attraction is reduced by the
sun's attraction
• High tides are not as high as
usual and low tides not as low

20. SPRING TIDES AND NEAP TIDES
The Bay of Fundy at high tide The Bay of Fundy at low tide

21. HOW ARE TIDES USEFUL?

The rise in water during high tide
allows big ships to enter or leave
harbors safely.

During high tide, water rushes up
the mouths of rivers. This helps
ships to move in and out of river
ports.

The saline waters of the sea
freeze at a lower temperature
than river water does. In cold
countries, the sea water rushing
in during high tide prevents
harbors from freezing in winter.

22. CONCLUSION
• Wind waves are the most common type of wave in the
ocean and are found superimposed on currents, tides,
and tsunami.
• There are different types of waves they can classified
depending upon velocity of waves.
• The wind transfers some of its energy to the water,
through friction between the air molecules and the
water molecules. Stronger winds (like storm surges)
cause larger waves.
• Tides are play major role in the sea or ocean transport.
• The water in the ocean tides moves back and forth
and these mass redistributions cause periodic loading
of the ocean bottom

23. REFERENCE
• Oceans and Oceanography By John P. Rafferty –
2011
• Waves, Tides, and Shallow-water Processes by John
Wright, Angela Colling, Dave Park, Open University.
Oceanography Course Team 1999.
• www.googleimages.com
• www.Wikipedia.com

24. THANK
YOU!!!