Coasts

Question 1

What is a coast?

Answer 1

Dynamic interface where land, sea, and atmosphere meet and interact.

Question 2

What is the main natural agent responsible for sediment detachment, transport, and deposition along coasts?

Answer 2

Waves

Question 3

Define wave base.

Answer 3

Wave base is the depth below the water surface at which wave motion is negligible—approximately half the wavelength.

Question 4

What happens to wave velocity as waves approach shallow water?

Answer 4

Wave velocity decreases.

Question 5

What is longshore drift?

Answer 5

Movement of sand along the shore caused by oblique wave approach and longshore currents.

Question 6

Wave height decreases as waves enter shallow waters.

Answer 6

False — wave height increases.

Question 7

Waves approaching headlands concentrate energy and cause erosion.

Answer 7

True

Question 8

Barrier islands are always attached to the mainland.

Answer 8

False — they are separated by lagoons or marshes.

Question 9

A spit always grows perpendicular to longshore drift.

Answer 9

False — it grows in the direction of longshore drift.

Question 10

A tombolo connects an offshore island to the mainland.

Answer 10

True

Question 11

When waves enter shallow water, which change occurs?

Answer 11

Wavelength shortens

Question 12

Wave refraction causes:

Answer 12

Energy concentration on headlands

Question 13

Longshore currents move:

Answer 13

Parallel to shore

Question 14

A cuspate foreland forms where:

Answer 14

Waves approach from two directions

Question 15

A wave-cut platform forms due to:

Answer 15

Continuous cliff erosion

Question 16

When depth is more than half the wavelength, the wave is in ______ water.

Answer 16

deep water

Question 17

Longshore currents move parallel to the beach within the ______ zone.

Answer 17

surf zone

Question 18

A ______ forms when a spit joins an offshore island.

Answer 18

tombolo

Question 19

A narrow ridge of sand growing outward from a bay mouth is a ______.

Answer 19

spit

Question 20

A wave-cut ______ forms at the base of an eroding cliff.

Answer 20

notch

Question 21

Rock bridge formed by erosion

Answer 21

Sea arch

Question 22

Narrow sandy ridge attached to land

Answer 22

Spit

Question 23

Offshore sandy island separated by lagoon

Answer 23

Barrier island

Question 24

Isolated pillar of rock

Answer 24

Sea stack

Question 25

Flat surface formed by cliff retreat

Answer 25

Wave-cut platform

Question 26

Explain how wave refraction affects headlands and bays.

Answer 26

Headlands receive focused wave energy → erosion Bays receive dispersed energy → deposition

Question 27

What causes breakers to form near shore?

Answer 27

Decrease in wave velocity as water becomes shallow → crest becomes steep → wave breaks.

Question 28

Describe the process of longshore drift.

Answer 28

Oblique wave approach pushes sand up the beach; backwash pulls it down perpendicular → zig-zag transport along shore.

Question 29

How does a wave-cut cliff form?

Answer 29

Constant wave erosion at the base creates a notch; cliff becomes unstable and collapses.

Question 30

How does a barrier island form from a spit?

Answer 30

Spit grows by longshore drift → tidal inlets cut through → isolated sandy island.

Question 31

Why are coastal areas highly dynamic?

Answer 31

Because they are influenced simultaneously by land processes, marine processes, and atmospheric conditions.

Question 32

Explain how multiple wave-cut terraces form.

Answer 32

They indicate repeated sea-level drops or tectonic uplift, each producing a new erosional platform.

Question 33

Describe how annual storm events accelerate coastal erosion.

Answer 33

Storm waves have higher energy → rapidly undercut cliffs → cause mass wasting → reshape coastlines. (Example: Tusang Beach.)

Question 34

What are the environmental impacts of coastal human activity?

Answer 34

Construction, dredging, seawalls, and pollution accelerate erosion or disrupt natural sediment movement.

Question 35

Differentiate between rocky coasts and sandy embayments.

Answer 35

Rocky coasts: dominated by erosion, cliffs, platforms Sandy embayments: dominated by deposition, beaches, spits

Question 36

Describe the transition of wave behavior from deep to shallow water.

Answer 36

Include: Wave base Wavelength shortening Height increase Velocity decrease Steeper wave crests Formation of breakers

Question 37

Explain how tombolos and cuspate forelands form.

Answer 37

Tombolo: spit grows until it connects an offshore island; controlled by wave refraction. Cuspate foreland: sediment accumulates where waves approach from two directions.

Question 38

Discuss the sequence of coastal erosion features from headland to stack.

Answer 38

Headland → sea cave → sea arch → collapse → sea stack.

Question 39

Outline the formation and evolution of spits and barrier islands.

Answer 39

Steps: longshore drift → spit formation → spit extension → tidal cut-through → barrier island development.

Question 40

Evaluate the role of wave refraction in shaping coastlines globally.

Answer 40

Include energy distribution, erosion intensity, depositional pattern, and long-term coastal morphology formation.

Question 41

If a coastline shows rapid cliff retreat, what coastal process is dominant?

Answer 41

Wave undercutting and cliff failure (erosion). Example: Tusang Beach.

Question 42

A curved sandbar grows across a bay mouth. What feature is forming?

Answer 42

Spit

Question 43

If waves approach from NE and NW directions, what morphology is likely?

Answer 43

Cuspate foreland

Question 44

What coastal type is likely where cliffs, platforms, and arches dominate?

Answer 44

Rocky erosional coast.

Question 45

A platform with multiple terrace levels suggests what history?

Answer 45

Several episodes of sea-level change.

Question 46

Why are spits excellent indicators of longshore drift direction?

Answer 46

They grow in the same direction as dominant sediment transport.

Question 47

Explain how wave refraction creates both erosional and depositional landforms along the same coastline.

Answer 47

Concentrated energy at headlands → erosion; dispersed energy in bays → deposition.

Question 48

Why do wave-cut platforms eventually become abandoned terraces?

Answer 48

Tectonic uplift or sea-level fall raises the platform above active wave erosion.

Question 49

How can humans unintentionally increase coastal erosion?

Answer 49

By building seawalls, groynes, or altering sediment supply, which intensifies wave attack elsewhere.

Question 50

Why are barrier islands extremely vulnerable to climate change?

Answer 50

Rising sea levels and stronger storms reshape islands, breach inlets, and migrate barriers inland.