Lecture 8 Coastal Hazards Flashcards
what are the major coastal hazards
landcapes where cinentts meet oceans, dynamic and capcble of rapid change, include rip current, erosion, seal level rise, storm surges and tusanami
what are the 2 coastal margins
coast lines can be influenced by plate techtonics
passive margins: distant from plate cboudnries, wide continential shavles, snady beaches and barrier islands
active margins: relatively close to plate boundires, rocky shores and sea cliffs
what does the size of a wave depend on
velocity of wind, duration of wind, and fetch (distance of wind)
describe the motion of waves
circular, circles decrease in diameter with depth because engery decreases withdpeth
what are sweels
set of waves genreated by storms fa out at dea, predicted using equation, as approach the land become unstable
what are the types of wave breaks
plunging breakersL forma on steep beaches, erosive high energy
spilling breakers: wide gently sloping beaches less erosive
what are tidal bores
waves the form when inflowing tidal water is slowed by outslowing river water
what are the different parts of the beach
sea cliff; worded landform that marks the landward boundry of the beach
berm: an onshor portion of the beach that is generally falt and formed by deposition of sediment
beach face: on shore portion of the beach that slopes seaward lies within swash zone
surf zone: an area where waves move toward the shore after they break
breaker zone: an area wher eincoming waves peak and break
lond shore barL a low ridge on the sea floor in the breaker zone
long shore trough: a depression on the sea floor formed by ave action land ward of the long shore bar
what is littoral transport
sand movment paallel to the shore, two processes
beach driftL snad moving in a zig zag pattern in the swash zone
long shore drift: transport of sediment by current that flow parallel o the shore ling
what are barrier islands
long narrow islands seperated from the land land by a bay of lagoon
what are eutasy
global changes in sea level
what are ripcurrents
undertow, horiztonal currents that move away from a shoreline, develop when waves pile up water bettern thelong shor bar and the swash zone, a breakage developed in the long shore bar and the water rushes back through tht brek
what are the linkages with other naural hazards
earthqukes, volanic eruptions all can change he shape of the shorline
erision
landlisdes can be caused by eroded cliffs
climate ahcge is causing more intense tropical storms and high sea levels
what are the nautral service functions
seceiv coastal landscape and bluffs are a reuslt of erosion, beaches are mamainted by constant depostion of sediment
popular tourist attraction
what are the human interactions with the coastal process
barrier islands are popular locations, removal of coastal sand dunes for consitruction and left areas vulnerable to storm surges, resulting loss o sand has led to erosion occuring
