Marine Processes

Aim
  • types of waves
  • component of waves
  • erosional processes: corrasion, corrosion, hydraulic action, attrition
  • onshore and offshore movement
  • longshore drift
  • wind actions and dunes

Waves

  • energy transmitted through matter
  • the medium (solid liquid gas) does not actually travel as the energy passes, but its particles vibrate as the energy passes through
  • Progressive waves
  • Size of wave depends on fetch= distance a wave travels
  • The greater the fetch, the larger the wave
  • The stronger the wind, the larger the wave
  • As the wave approaches the beach, it slows down due to friction between water and beach, and this causes the wave to break.
  • terms: break, swash, backwash
  • If swash is bigger than backwash, more deposition occurs so beach is created. If backwash is bigger than swash, beach is destroyed
  • Destructive waves destroy beaches. Back wash has less time to soak into sand. So it carries a lot of sand with it. As waves continue to hit the beach, more running water carry material to the sea.
  • Wind generated waves originate in windy places of the ocean
  • They keep on moving along large areas without the aid of wind
  • As wind blows over ocean surface, it creates pressure that deform the surface of the ocean
  • If power increases, it becomes gravity waves

Prevention and Cause of volcanic eruptions

Definitions for commonly used terms

Hazard– thing (usually has dates)

Risk– chance/likeliness

Disaster– occurence

 

Volcanic Features

Eruption column and cloud– volcanic ash emitted during volcanic explosion. Ash forms a column rising many km into air above peak of volcano. Eruption cloud- cloud that forms when volcano erupts. Lung problems, harm ecosystem.

Volcanic gases– Gas ejected of volcanoes during eruption.

Lava flow and domes– Lava dome is created by volcanic eruption. Forms when lava flow is too thick to flow, and piles up on the side, creating a steep side. Lava flow- movement of lava created during non-explosive eruption.

Pyroclastic Flows– Flow of ash, rocks, and gas down the volcano, carrying everything on its pathway.

Lahars– Type of mudflow, contains: pyroclastic material, rocky debris, and water.  Over 60km/hour. Material flows down volcano, occurs along river valley.

Edifice collapse– Structure of volcano collapse.

Hot springs and Geysers– Hot springs- Warm water above body temperature. Heated naturally. Above ground. Geyser- When spring releases hot water and steam into water, from hole in ground. Occurs due to build up of pressure.

Other notes: http://greenfieldgeography.wikispaces.com/IGCSE+Plate+Tectonics+and+GCSE+Plate+Tectonics

Noted from video.