Waves are generated by wind blowing over the surface of the ocean. The document defines different components of waves like crest, trough, wavelength, height, and period. It discusses different types of waves such as wind-generated waves, tsunami waves, tidal waves, and rogue waves. Waves are classified based on the generating force, water depth, geomorphic significance, and how they break. Deep water waves occur in deep ocean water while shallow water waves interact with the sea floor near the shore.

1. WAVES
DIVYA DAS S S
ASST PROFESSOR OF GEOGRAPHY
GOVT ARTS AND SCIENCE COLLEGE,
KULATHOOR

2. WAVES
●
Sea waves are defined as undulations of
sea water characterized by well-developed
crests and troughs.
●
The undulations of sea water at the place
of their origin are called swells, which are
low, broad, regular and rounded ridges
and troughs of water.

4. Components of seawaves
●
Wave Crest- upper part of a wave
●
Wave Trough- lower part of a wave
●
Wave length- The straight horizontal
distance between two
successive crests or troughs.
●
Wave height- the vertical distance
between the crest and trough.

5. Continued....
●
Wave period- The time taken by a sea wave to
cover the distance of one
wavelength or wave cycle.
●
Wave frequency- The number of sea waves
passing through a certain point
per unit time (usually one second)

6. Terms to remember
●
Fetch- the distance or length of sea surface over
which the wind blows in one direction for longer
duration.
●
Sea area- the area of the ocean where sea waves are
generated by winds and radiate in all directions.
– Breeding area of wind generated waves
●
Plunge line- the distance from the sea shore where
the waves break due to shallow water depth and
enormous wave height
●

7. ●
Swash/ surf waves/ uprush- the foaming
waves rushes upto the beach generated
by breaking of waves at the plunge line
●
Backwash- body of foaming waves
returning down to the sea.

8. WAVE FREQUENCY

9. GENERATION OF SEAWAVES
●
Atmospheric circulation and wind
●
Movement of fluids of two contrasting densities
along the interfaces of two masses of fluids of
varying densities
●
Movement of water masses of varying densities in
the oceans such as turbidity currents
●
Mass movement into the oceans such as landslides in
the coastal areas.

10. Continues...
●
Tectonic activities on the sea floor such as faulting,
thrusting etc.
●
Occurence of undersea earthquakes, known as
tsunamigenic quakes.
●
Undersea volcanic eruptions
●
Gravitational forces of the sun and the moon- tidal
waves
●
Atmospheric storms such as tropical cyclones
●
Anthropogenic activities- undersea nuclear tests and
explosions

12. Types of sea waves
●
On the basis of wave generating force
– Wind generated sea waves
– Undersea landslide generated sea waves
– Tectonic sea waves
– Tsunami waves
– Tidal waves
– Storm surges
– Volcanogenic sea waves

13. Classification continues...
●
On the basis of depth of sea water
a) deep water waves or oscillatory waves
b)shallow water waves or translatory waves
c) transitional waves
●
On the basis of geomorphic significance
a) constructive waves
b) destructive waves

14. Classification continues....
●
On the basis of breaking of waves
a) spilling breakers
b) plunging breakers
c) surging breakers
d) collapsing breakers
●
On the basis of multiple causes
a)swell waves
b) rogue waves
c) surf waves

15. Wind Generated Waves
●
Sea waves are generated due to friction on water
surface of the oceans by gusty winds.
●
Wind generated waves vary in size, speed and
directions.
●
Controlled by:
– Velocity of the wind
– Duration of the wind blowing in one direction
– Extent of fetch
– Original condition of the sea.

16. Continues....
●
The wind generated sea waves pass through a life cycle
– Stage 1: generation of small and young waves
– Stage 2: their development in terms of WL, WH & velocity
– Stage 3: movement of waves
– Stage 4: their termination when they break either in open
sea or at plunge line near the sea shore and
release their energy.

17. Stages of development of waves
●
Ripples or capillary waves- initial sea waves
with shortest wavelengths, usually less than 2
cms and having rounded crests and V-shaped
troughs
●
Gravity waves- as winds blow in the same
direction, the capillary waves develop into larger
waves with more energy and longer
wavelengths, usually more than 2cms and upto
10 meters.

18. Continues....
●
Fully developed sea- the stage of
maximum development of sea waves,
when sea waves attain maximum wave
height and wavelength under certain
condition of wind speed
●
Surf waves- the waves leave the fetch
area and break at the plunge line and
advance coastward as surf waves.

19. ●
Also called oscillatory
waves
●
Waves generated in the
deep ocean water by
winds.
●
They do not have any
interaction with the
ocean bottoms.
●
The water particles move
in orbital cycle and they
return to their original
position after the passage
of waves while wave
form or wave energy
move forward.
●
Also called translatory
or long waves.
●
The sea waves travelling
in shallow water zone
near the shore
●
They touch the bottom
of the oceans.
●
The water particles in
such wave follow
flattened orbits and
hence there is forward
movement of water
mass also.
Deep water waves Shallow water waves

21. Transitional waves
●
Also called intermediate waves
●
The sea waves between deep water waves and
shallow water waves.

22. Rogue waves
●
Also called super waves or monstrous waves
●
The occasional and unusual or non-regular sea waves
of enormous wave height.
●
Very severe and destructive
●
The collision of strong storm waves generated by
powerful atmospheric disturbance and strong ocean
currents results in the genesis of rogue waves becxause
the collision force causes steepening and shorteninng of
storm waves which ultimately are tramsformed into
monstrous waves.

24. ●
Low frequency waves
with longer wavelength
and lower wave height
●
Have a strong swash
and weak backwash.
●
Deposition is greater
than erosion
●
Helps in the building of
beaches
Constructive waves
●
High frequency waves
with shorter wavelength
and higher waveheight
●
Have a weak swash and a
strong backwash.
●
Erosion is greater than
deposition
●
Removes the beach
materials and transports
them towards the sea
Destructive waves

25. Breakers
●
Spilling breaker- those in which water doesn’t
fall but gradually spills down the front of sea
waves and forms prominent foaming coast
– Associated with steep waves
●
Plunging breakers- those in which water falls vertically
and rushes shoreward in the form of turbulent
watermass.
– Associated with intermediate waves
●
Surging breakers- those in which water moves rapidly
shoreward.
– Associated with gentle waves