Tsunamis are considered destructive waves. They have high wave heights that can cause powerful breaking waves and significant erosion. Erosion transports sediments away from the coast. Constructive waves are smaller with less powerful breakers that cause minimal erosion and may deposit sediments on the coast. Factors like wave frequency, backwash, coastal slope gradients, and coastal positioning determine whether a wave is destructive or constructive.

1. 1

2. Q: Are tsunamis considered as
destructive or constructive
waves?
2

3. Q: Are tsunamis considered as
destructive or constructive
waves? Issues:
wave frequency? no backwash?
gentle slope or sheltered
coast?
Destructive:
- high wave height/ plunging
breakers
- erosion process more prominent
- transports eroded sediments
away
3

4. Text pg Tides
91
• Rising and falling
of the sea level
• Cause : pull of the
moon & sun,
rotation of the
earth
• Each coastal area
receive two high
tides and two low
tides daily
4

5. W ic a a n h bah t
h h r o t ec ish
e e e
Tides
m spoe oe s n
ot rn t r io?
o
Aes
ra
bten
e e
w
high and
low te
ids
hv m r
ae oe
e sn
r io
o
5

6. 6

7. LSON OB C I
ES JTE
E V
• Todescribe and
explain the 4 coastal
erosion processes
• D escribe
what a
longshore drift is
( time?)
7

8. 3 OA T L R ESS
Erosion C orrasion
C SA P OC SE
A brasion
Solution
H ydraulic action
T ransport
Longshore drift
D eposition Fc r
at s
o:
-Supply of sediment
-G radient of slope
-C oast position
8

9. C SA E OS
OA T L R I
ON
Txp 9
et g 2 More erosion Less erosion
Types of waves - et c e ae - osute ae
D sut wvs C nt c wvs
r iv r iv
( oe nr )
m r ee y
g (es nr )
l ee y
s g
Structure and -N mru le o -N c cs
u e s sf o rk
o in a
composition of wans
ekes -H r rcs
a ok
d
coastal rocks -Sfrcs
o ok
t
Position of the -Opn os
e cat -Poet ad
rt e n
cd
coast see d y
hlr b
te
9 sut e
tc r
r us

10. G OU W K
R P OR
• Ec g u t r e e
ah r p o e iv
o c
oe aga setn 4
n vnur he ad
d
mr r
ae
ks
• W ilwitgt hn u
he ain, o ad p
hmwrinrn
o e ok f t
o
• T oe ht a nt
hs t hs o
a
cmle, t s y ak
o p t o t bc
ed a
drgeeso o
uin r st d .
c
1
0

11. G OU W K
R P OR
• D etermine which erosion process has created this coast : C orrasion/
A ttrition/ Solution/ H ydraulic action
• W rite down the characteristics and traits of the coastal features
• Explain how the erosion process occur
• T extbook time
• T eacher time
1
1

12. C R S /B A I
OR A I A R S
ON ON
• Ipco t mt ia c rd
mat fh a rl a ie
e e s r
b t wvsc p g gint
yh ae s ain aa s
e r
t ca ( g 3
h os p 9)
e t
• T r l c o t cr n
ub e e fh ur t
un e es
po ue s uin eet
rdc a c rg fc
o f
• C islg fc/rd g
hein eet g in
l f in
atn n h ca
c o t os
io e t
• C t g n b ain t rc
u in ad r k gh ok
t e e s
o t ca s
n h os
e t
1
2

13. A T ION
TR I
T
• R csu o h aa sec
ok rb r itgint ah
ohr r k d w in s a
t , be s o n t ml
e a o l
rud m oh iee( g 3
on s o t p cs 9)
p
• Mt ia f m h wvs
a rl r t ae
e so e
cl e it mt ia o t
oid wh a rl n h
l e s e
ca
ost
• Ipccue mt ia t
matass a rl o
e s
bek t s a r iee
r in ml p cs
a o l
e
wic bcmsad
h h eo e sn
1
3

14. SM A Y
U MR
• A s e d t et us n b u dsute
nwr s dn qet aot et c
e u io r iv
ad osute ae
n cnt c wvs
r iv
• D fitn f ids
e io o T e
in
• D s ib t ca c rts f ca ae s n
ec e h hr t is o 4 os lr ioa
r e a e ic t o
poes A H
rcs C S
:
• Ep ind o t p cs s c r
xl e hwh r es oc s
a e o e u
1
4

15. S U I /OR OS
OL TON C R ION
• W vsecce icl wh
ae r thm a it
a ly
sl lm e l t rcs
o b inrs h ok
ue a in e
ad is l t m p 9)
n ds v h ( g 3
oe e
• C r s n fok b
or io o rcs y
o
sa a r
ewt e
• W v atn c a sh r e
ae c inr s t a
io ee e t
o r c n ye oin t
fe t b r v gh
a io m e
r c d hm aslio
e t ce icl u n
ae ot
• E l etn
gims e
o
1
5

16. H E OR A S E S
OMW K N W R ON BOG
L
1
6

17. HDAL AT
Y R UI C I
C ON
• D et pco t wvs ginth
ir imat fh ae aa st
c e e
ca . C mr s irn ee
os o pe a ad xr
t s t
pesr in h c cs fok ( g 2
r ue t r k o rcsp 9)
s e a
• Elgsins f ekess fr
n r le o wans ae
ae e t
r et c se o wvs
e a d r hs f ae
p e a
• C avitation: wt sr s t c cs
a rug in r k
e e o a ,
j t f l. R sl in o pesd ir
o s a t eus cmr e a
in , us t s
ad ud pesr W t r r t
n bil r ue a re e
s s . e ta
ress r sr ad r pd ir
e a pe ue n t pe a
l e s a
wic bek t rc u.
h h r sh ok p
a e
1
7

18. L GH E RT
ON S OR D I
F
1
8

19. Coasts are shaped by ...
Text pg
Currents 189
• Large scale
movement of
water in the ocean
driven by wind
• Longshore
current: flow
parallel to a coast
( form by waves
approaching at an
oblique angle)
1
9

20. OL eg 20 P Q4
G o N 04 2 QUZ
I
U sing a labelled diagram,
describe the process of
longshore drift [ 4]
2
0

21. P 9
G 3
C SA T A SOR A I
OA T L R N P T TON
• Longshore drift: wvsr soteimn a n t ca
ae t np rsd etl gh os
a o e t
• Longshore drift: beach drift + longshore current
• W v apoc ca aa ag : S a cr s a rl o lu
ae prah os tn nl ws a ie mt ia in b e
t e h r e s iq
ag
nle
• Bcws cr s a rl e ed u r d w bcue fr it
ak a a ie mt ia pr nicll o n eas o g vy
h r e s p ay a
• Z zg oe et ec dif sd etm v g l g ec)
iga m vmn bah r ( eimn oin a n bah
: t s o
2
1

22. LO N G SH O RE D RIFT
2
2

23. ( beach drift)
Longshore current
DA R M L G H E
IG A OF ON S OR
DI
RT
F
2
3

24. U in aaee d g mds ib t poes
sg l ld iar , ec e h rcs
bl a r e
o l g oe r [ ]
f ns r dif 4
o h t
• W aves reach the coast at an oblique angle creates a longshore
current
• T he materials move in a zigzag pattern in a down drift
direction ( beach drift)
• T he swash carries materials up the beach at the same angle as
when the war approaches the shore
• A s the swash dies away, the backwash and any materials
carries by it return straight down the beach at right angles to
the water line due to gravity.
• Longshore drift = beach drift + longshore current
2
4

25. C SA D P ION
OA T L EOS I
T
More Less
P9
g4
deposition deposition
W a wv ee y
ek ae nr g
Supply of S og ae nr
t n wv ee y
r g
E cnt c e
g osut
r iv
sediment e dsute ae
g et c wvs
r iv
wvs
ae
G ne g d n
etrr iet
l a
G radient of
r ue wv ee y S e g d n
e cs ae nr
d g t p r iet
e a
slope bcue f ic n
eas o f t
r io
C l cs l
a ot
m a
Position of
cnitn/ rt t
odiospoe ecd Opn os
e ca s
t
the coast by
as
2
5