8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 1/17

SHORELINES

a) Wavesb)Longshore transport

c) Erosional shoresd)Depositional shorese) Emergent and submergent shores

f) Sealevel rise

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 2/17

= orbital wave (waves ofoscillation)

Energy advances

But:

Water does not!Water moves in circular orbits

Ocean WAVES

a) Wavesa) WavesShorelinesShorelines

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 3/17

Waves ‘feel bottom when it comes to within half of thewavelength

Wave length decreases wave height increases "t critical #oint the wave becomes too stee# and brea$s

Surf sloshes onshore

Breaking WAVES

%ig& ' &'

a) Wavesa) WavesShorelinesShorelines

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 4/17

Summertime and wintertime beach conditions

Summertime beach Wintertime beach

a) Wavesa) Waves

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 5/17

Wave refraction strongly influences erosion and sediment transport

Waves travel moreslowly in shallow waterso they refract towards

the beach.

a) Wavesa) Waves

Waves refract aroundheadlands, increasing

wave impact onheadlands, decreasing it

on beaches. Fig. 17.13

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 6/17

Longshore transport • Swash is oblique,

bac wash straight,causing beach drift of

sediment along the shore

• !blique waves also causelongshore currents parallel to beach

b) Longshore transportb) Longshore transport

Beaches = *ivers of sand!Beaches = *ivers of sand!

ShorelinesShorelines

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 7/17

Longshore currents and rip currents

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 8/17

Wave refraction along an irregular shoreline

• Wave energy isconcentrated atheadlands anddispersed in

bays• Causes erosion

of headlandsand creation oferosionalfeatures Figure 10-1 b

c) Erosional Shoresc) Erosional ShoresShorelinesShorelines

%ig& Story ' &'

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 9/17

• !eadland• Wave-cut cliff • Wave-cut

terrace"bench#• Sea cave• Sea arch• Sea stac$

c) Erosional Shoresc) Erosional ShoresShorelinesShorelines

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 10/17

ShorelinesShorelines

BEACHES

+ Source of beach sediments

, rivers, cliff erosion, marine life

+ Sand com#osition

d) Depositional Shoresd) Depositional Shores

Beaches

See %ig& ' &'-

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 11/17

ShorelinesShorelines

BEACHES

+ Source of beach sediments

, rivers, cliff erosion, marine life

+ Sand com#osition

d) Depositional Shoresd) Depositional Shores

See %ig& ' &'-

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 12/17

• Spit

• %ay barrier"baymouth bar#

•&ombolo• %arrier island

• 'elta

d) Depositional Shoresd) Depositional ShoresShorelinesShorelines

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 13/17

Emergent coasts

Develop because of uplift of an area or adrop in sea level

"eatures of an emergent coast ( Wave#cut cliffs ( Wave#cut platforms

e) Emergent and submergent coastse) Emergent and submergent coasts

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 14/17

)plifted* ancient wave-cut benches e+posed in southern California

e) Emergent and submergent coastse) Emergent and submergent coasts

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 15/17

Submergent coast

$aused by subsidence of land ad%acent tothe sea or a rise in sea level

"eatures of a submergent coast ( &ighly irregular shoreline ( Estuaries ' drown river mouths

e) Emergent and submergent coastse) Emergent and submergent coasts

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 16/17

Chesapeake Bay is a goodexample of a submergent coastline

e) Emergent and submergent coastse) Emergent and submergent coasts

8/20/2019 04. garis pantai_2014(1)

http://slidepdf.com/reader/full/04-garis-pantai20141 17/17

f) Sea-level risef) Sea-level rise

Fossil fuelburning has addedgreenhouse gases toatmos#here

Sea-level rise:

thermal e.#ansion ofseawater and ice,sheetmelting /mm0yr 12,32 cmduring this century

Global warming follows(u# to 2&4 5 in #ast century)