Oceans and coasts

Factors that impact coastlines

1. Tectonic setting

2. Materials present at the shore

3. Energy of water and wind striking the coast

Waves

Small undulations on the water surface that are generated by wind

Propagate through water away from source

Modifies shorelines when they break

Tides

Small variations in local sea level due to gravitational effects of both the Sun and the Moon

Creates currents

Bay of Fundy has the highest tides in the world

Storm surge

Localized increase in water level of an ocean or large lake

1. Caused by the high winds and extreme low pressure associated with major storms

Factors that affect the magnitude of the surge are

1. Speed at which the storm approaches the coast

2. Geometry of the particular coastline

Tsunamis

1. Caused by earthquakes, landslides, or volcanic eruptions

2. Can travel across entire ocean basins with minimal energy loss

Beaches

Gently sloping depositional surfaces washed over by waves and covered by sediment

Change seasonally with more fine grained sand in the summer and rocky during the winter, This is because of wave energy and the resulting movement of sand and other sediments (winter = less waves but stronger, summer = more waves but weaker)

Emergent vs Submergent coastline

Emergent

1. When water is getting lower relative to the local coast

Submergent

1. When water is getting higher relative to the local coast

Currents

Distinct bodies of water moving in a definite direction

Wave-cut platforms

Form when land is elevated or sea level falls

Littoral drift

Gradual sand movement down the beach in the same general direction as the motion of the longshore current

Longshore current

Net movement of water parallel to a coastline, arising when waves and currents approach the shore at an angle

Storm tide

The overall water level during a storm, Sum of storm surge + normal tides