Which coastal process causes zigzag movement along the shore due to oblique waves?

• A. Swell profile
• B. Longshore current
• C. Beach nourishment
• D. Storm profile

Answer: (B)

Oblique wave approach creates a current that runs along the coast, called the longshore current. As waves hit the shore at an angle, water and sediment are pushed along the coastline, producing continuous alongshore transport of material. This movement causes the beach to erode in some areas and accrete in others, giving the shore a zigzag pattern as sediment is carried in the direction of the current and deposited where conditions change. This alongshore transport is the key mechanism behind the zigzag movement seen with oblique waves.

Other options don’t describe this persistent alongshore process: swell profile relates to the shape and characteristics of incoming waves rather than sediment transport along the coast; beach nourishment is a human intervention that adds sediment without explaining natural zigzag movement; storm profile refers to changes during storms and doesn’t capture the regular alongshore drift driven by oblique waves.