9GE01 - 3.3 - Longshore Trips

What can stabilize tombolos and cuspsate forelands?

• Urban development

• Vegetation

• Offshore drilling

• Artificial reefs

Answer explanation

Vegetation can stabilize tombolos and cuspsate forelands by reducing erosion, promoting sediment accumulation, and providing habitat for other stabilizing organisms.

What is the angle at which swash is most efficient for longshore drift?

• 90°

• 45°

• 30°

• 60°

Answer explanation

A 30° angle is most efficient for longshore drift as it maximizes the movement of sediment along the coast without causing excessive erosion or deposition.

Which type of wave movement results in the most deposition?

• Destructive waves

• Constructive waves

• Refracted waves

• Orthogonal waves

Answer explanation

Constructive waves result in the most deposition by depositing sediment on the shore due to their strong swash and weak backwash.

What is the direction of sediment transport in a drift aligned coast?

• Perpendicular to the shoreline

• Parallel to the wave crests

• In the direction of the prevailing wind

• At 90° to the wave orthogonals

Answer explanation

Sediment transport in a drift-aligned coast occurs in the direction of the prevailing wind, influencing the movement of sediment along the shoreline.

What causes the backwash to move out perpendicular to the shoreline in a drift aligned coast?

• Wave refraction

• Marine transgression

• Gravity

• Prevailing wind

Answer explanation

In a drift-aligned coast, the backwash moves out perpendicular to the shoreline due to gravity pulling the water back towards the ocean.

What is the result of wave refraction around headlands?

• Wave energy converging on headlands

• Wave energy diverging in bays

• Limited longshore movement

• Both A and B

Answer explanation

Wave refraction around headlands results in wave energy converging on headlands and diverging in bays, leading to limited longshore movement. Therefore, the correct answer is both A and B.

What happens to the transport of material when interference occurs?

• The transport of material continues in the same direction

• The transport of material is accelerated

• The transport of material is stopped or changed

• The transport of material is unaffected

Answer explanation

When interference occurs, the transport of material is stopped or changed, affecting the movement of the material.

What is affected by wave refraction?

• The color of the waves

• The salinity of the water

• The energy levels and direction of material transport

• The temperature of the water

Answer explanation

Wave refraction affects the energy levels and direction of material transport, causing waves to bend and change direction as they interact with varying depths.

During distance decay/gravity settling, what happens to larger material?

• It is transported further

• It is broken down into smaller pieces

• It is deposited

• It floats on the water surface

Answer explanation

During distance decay/gravity settling, larger material is deposited, meaning it settles to the bottom rather than being transported further or broken down into smaller pieces.

What happens to smaller material as a result of distance decay/gravity settling?

• It is immediately deposited

• It is transported further or deposited later

• It dissolves in the water

• It rises to the water surface

Answer explanation

Smaller material is transported further or deposited later due to distance decay/gravity settling, rather than being immediately deposited, dissolved in the water, or rising to the water surface.