tides

Tidal range

The difference in height between high tide and low tide.

Spring tides

Tides with a higher-than-normal tidal range that occur when the Earth, Moon, and sun are aligned.

Neap tides

Tides with a lower-than-normal tidal range that occur when the Moon is at right angles to the Earth-sun system.

Wave height

The vertical distance between the crest and trough of a wave.

Wavelength

The horizontal distance between two adjacent crests or troughs of a wave.

Wave base

The depth at which particle motion is negligible, equal to half the wavelength.

Swash

The movement of water up the beach in the direction of wave motion.

Backwash

The movement of water down the beach in the direction of greatest slope.

Longshore currents

Currents of water and sediment moving parallel to the beach.

Rip currents

Strong currents that flow away from the shore.

Wave refraction

The bending of waves as they approach the shoreline at an angle.

Breaker

A collapsed wave that rushes up the shoreface.

Surf

Turbulent water related to breaking waves.

Coastal erosion

The process by which coastlines are eroded by wave action.

Sediment transport

The movement of sand and other materials along the coast by wave action.

Spit

An elongated ridge of sand or gravel that projects into a body of water.

Baymouth bar

A ridge of sediment that extends completely across a bay.

Barrier islands

Long, narrow sandy islands lying offshore and parallel to the coast.

Tidal bore

A wave of water during a rising tide that moves upstream against the current.

Intertidal zone

The area between high tide and low tide.

Wave height increase

As wind speed increases, the wave height also increases.

Fetch

The length of water surface over which the wind blows, affecting wave height.

Oceanic waves

Waves produced by wind blowing over the surface of the ocean.

Wave period

The time it takes for successive crests to pass a given point.

Erosion zone

The area below sea level where wave-induced erosion occurs.

Coral reef

A marine structure formed from colonies of calcium carbonate-secreting microorganisms.

Drowned river valleys

Coastal features created by rising sea levels, forming estuaries.

Wavecut bench

A flat area formed at wave base due to erosion.

Wavecut notch

An erosional feature forming at the base of cliffs due to wave action.

Summer beaches

Beaches that widen and flatten due to long-period waves depositing sediment.

Winter beaches

Beaches that narrow and steepen due to storm waves carrying sediment offshore.

Coastal dunes

Sand formations created in windy areas with a large sediment supply.

Fjords

Narrow, deep coastal inlets formed by glacial activity.

Volcanic island subsidence

The process that leads to the formation of atolls from fringing reefs.