Coastal Hazards

Question 1

definition of coast

Answer 1

is where the land and sea meet, and goes 50km back inland

Question 2

what is a coastal hazard model?

Answer 2

source, pathway and receptor model

Question 3

social aspects of coastal hazards:

Answer 3

fatality by gender/age, deprivation correlation (both local and country scale)

Question 3

what causes changes in sea level?

Answer 3

tides or wind (movement), glaciation (add or subtract), global warming (properties) and tectonics (basin volume)

Question 4

what is glacio-eustacy?

Answer 4

global sea-level changes resulting from terrestrial ice-volume changes

Question 5

what is glacial-isostacy?

Answer 5

process by which the earth’s crust seeks to reach equilibrium following loading or unloading by ice

Question 6

what are local changes that contribute to sea level rise?

Answer 6

subsidence (due to sediment weight) and tectonic control

Question 7

what are impacts from sea level rise effects?

Answer 7

inundation and loss of land and rising groundwater

Question 8

what are coastal retreat processes?

Answer 8

erosion occurs when the beach is out of equilibrium (Bruun rule/equation), barrier translation (coarser material migrating shoreward) and barrier overstepping (a large event causing barriers to be moved)

Question 9

what are options to deal with coastal retreat?

Answer 9

do nothing, managed realignment, hold the line and limited intervention

Question 10

characteristics of a tropical cyclone

Answer 10

form over large, warm bodies of water, between 100 and 4,000 km in diameter, energy from ocean surface evaporation and considered a cyclone when reaches 120km/h

Question 11

characteristics of a extra-tropical cyclone

Answer 11

known as depressions/lows, formed by horizontal pressure contrasts and form within extra-tropical regions

Question 12

what is a storm surge?

Answer 12

a rise above the normal water level along a shore resulting from reduced atmospheric pressure and strong onshore winds associated with a storm

Question 13

what are the pre-requisites for tropical cyclone formation?

Answer 13

large, still warm ocean water (exceeding 26.5 degrees). low altitude winds blowing from different directions

Question 14

what are the pre-requisites for extra-tropical cyclone formation?

Answer 14

large horizontal, near surface temperature gradient. strong winds in the upper troposphere (jet streams)

Question 15

what are some climate controls on cyclone activity?

Answer 15

ENSO circulation (surface temperature warming globally, forming more common cyclones) and climate change impacts increasing cyclone and storm frequency/intensity

Question 16

where are the largest drowning statistics from? why?

Answer 16

central Africa, Bolivia, Afghanistan due to cultural context leading to lack of training and experience

Question 17

what are the types of bathymetric rip currents?

Answer 17

channel rips and focussed rips

Question 18

when are rip currents at high risk?

Answer 18

low tide and when wave height increases

Question 19

how to manage rip current risk?

Answer 19

awareness, education, signage, rules and regulations

Question 20

what are tsunamis?

Answer 20

a large wave, or series of waves, caused by catastrophic displacement of water (a type of wave generated in a non-standard way)

Question 20

what are the four events that could cause a tsunami?

Answer 20

earthquakes, landslides (subaerial and submarine), volcanoes and asteroids

Question 21

where do tsunamis occur?

Answer 21

within the ring of fire - 60% within the Pacific ocean and a lot in the Mediterranean sea

Question 22

what are mitigation and evacuation practices for tsunamis?

Answer 22

sea walls, floodgates, pacific tsunami warning system, evacuation zones, training of locals and maps

Question 23

what are the short-term impacts from a tsunami?

Answer 23

land submersion, broken infrastructure (hospitals), fatalities, displacement, failed warning system, disease spread, salinity impacts (soil salination), and aid (wells etc.)

Question 24

what are the medium-term impacts from a tsunami?

Answer 24

river geomorphology and ecosystems change, estuarine system change (saltwater limit, sediment supply and river mouth location) and coastal retreat

Question 25

what are the long-term impacts from a tsunami?

Answer 25

uplift in water and land e.g. reefs, causing a long recovery time