Chapter 3 Wearing Down Landforms: Wind and Waves

Wind Erosion  Wind erosion occurs when sand and silt particles are removed from one area and blown against rock surfaces.

Wind Erosion  Deflation: the lowering or hollowing out of the land are from which the particles were removed from.  Hamada: a deflated landscape in which all loose particles are removed from; the land is bare, exposed rock.  Abrasion: the grinding away of bedrock by loose rock particles, blown by the wind

Wind Deposition  Erg: Airy, sandy desert areas.  Sand Dunes: A hill or ridge of sand sorted and accumulated by wind action.  Barchan: a crescent- shaped dune.  Loess: loose, fine- grained soil.

Wave Erosion  Lake and ocean water gets its energy from the wind, which transfers its energy to the water as friction. The result is a wave.  When waves strike shorelines, erosion results. The processes are parallel to that of river erosion.

Wave Erosion  Wave Movement and Direction: –In open water, waves develop in long ridges perpendicular to the wind. The waves bend to strike parallel to shorelines, called wave refraction. –Wave Refraction AnimationWave Refraction Animation

Wave Erosion –When the largest waves in a wave front strike the shoreline on an angle, loose sediment is removed. This is called longshore drift. –Long shore Drift Animation Long shore Drift AnimationLong shore Drift Animation

Effects of Wave Erosion & Deposition  The ways in which waves affect a coastline are depend on how it was formed: –Coastline resulting from rising sea levels: embayed shoreline, drowned/submerged coastline, ria coast (see fig 3.6, p.43)

Effects of Wave Erosion & Deposition –Coastline resulting from rising land levels: cliff- and-terrace, emergent coastline (see fig. 3.11, p.48-49)

Natural Disasters Caused by Wind and Waves (p.50)  Places all over the world have been affected by tornadoes, hurricanes, typhoons, tsunami and storms in general. Some places are more affected than others.  Read the case study, ‘Storm Surges in Bangladesh’ and respond to the questions handed out to you on worksheet 3.6. Hand it in at the end of class today.