SECTION C Flashcards
how do waves form
by wind blowing over the sea causing friction
how do tsunamis form
when earthquakes or volcanic eruptions shake the seabed
what are the two types of waves
destructive and constructive
when are constructive waves formed and how
summer and formed by storms often hundreds of kilometres away
when and how do destructive waves form
formed by local storms close to coast
winter
what are characteristics of constructive waves
create a gently sloping beach
low waves with wave crest far apart
what are characteristics of destructive waves
waves close together
little swash
high backwash
steep beach
what are the three types of weathering
mechanical, chemical, biological
an example of mechanical weathering is freeze thaw describe this process
where water collects in cracks in rock
at night, water freezes and expands making cracks larger
as temperature rises ice thaws and water seeps deeper into rock
repeated freezing and thawing makes rock fragments break off
what is mass movement and state the 4 types
it’s the downward movement of weathered material
- rockfall
- landslide
- mudflow
- rotational slip
what is solution
dissolving of soluble chemicals in rock eg limestone
what is corrasion
rock fragments picked up by the sea are thrown at the cliff. they scrape and wear away the rock
what is abrasion
the sandpapering effect of pebbles grinding over a rocky platform
what is attrition
rock fragments carried by the sea knock against each other becoming smaller/ more rounded
what is hydraulic action
the power of waves as they hit the cliff trapped air is forced inside cracks in the rock which eventually cause it to collapse
what are the four ways sediment is transported
- solution
- suspension
- saltation
- traction
how does longshore drift occur
- where waves approach ‘head on’ sediment moves up and down the beach
- where waves approach at an angle, sediment moves along the beach in a zig zag pattern
how are bays and headlands formed
: tougher resistant bands of rock are eroded to form headlands
:weaker rock erodes more easily to form bays
bays are sheltered, depositon occurs and a beach forms
describe the formation of a wave cut notch and how it turns into a wave cute platform
waves break against a cliff, erosion close to high tide line will form a wave cut notch. over time it deepens undercutting the cliff which eventually collapses. this process repeats and cliff fully collapses and retreats leaves behind a gently sloping rocky wave cut platform