Hazards Flashcards
Adaptation
People can prepare for the hazard to reduce hazard risk
Asthenosphere
softer semi-molten layer on which plates sit + move slowly
Atmospheric hazard
Driven by processes at work in the atmosphere
Tropical storms, droughts
Benioff zone
Inclined zone which deep earthquakes occur, situated beneath destructive plate boundary where oceanic crust is being subducted
Conservative plate boundary
2 plates move laterally past each other (transform margin)
No volcanic activity
Earthquakes occur frequency and low magnitude
Continental crust
Less dense
Convection currents
Heat driven cycles
Convergent plate boundary
O-o: subduction, island arc
Divergent plate boundary
Plates move away from each other due to diverging convection cell currents
When plates move apart in continental crust produce rift valleys
When move apart oceanic areas form mid-oceanic ridges
Space between plates filled with basaltic lava upwelling from below creating new crust
Fatalism
Do nothing
Acceptance hazards are natural events
Action concerned with safety first
Fear
People feel so vulnerable to event they no longer able to face living in area + move away to place perceived to be safe
Fold mountains
Occur due to conservative plate boundary
E.g. himalayas
As plates collide sediments are folded up into fold mountains
Geophysical hazard
Driven by earth’s own internal energy sources
Plate tectonics, volcanoes, seismic activity, landslide
Hydrological hazard
Driven by water bodies
Floods, storm surges, tsunamis
Integrated risk management
Analysing potential risks and implementing a coordinated approach to manage and reduce risks
Island arc
Chain of volcanic islands
Magma plume
hot spots - upwellings of superheated rock that rise from mantle towards surface - break through middle of tectonic plate causing volcanic eruptions and earthquakes
mitigation
actions aimed at reducing severity of event and lessening impacts - involve direct intervention (building design) or preparation barriers that may slow down/halt wildfires
natural disaster
occur as a result of a hazard and may potentially have enormous impacts on people and property
natural hazard
threat of substantial loss of life, substantial impact upon life or damage to property
oceanic crust
more dense
ocean trenches
deep depression in ocean bed, running parallel to plate boundary and marking subduction zone
rift valley
plates pull apart crust subjected to huge pressures causing fracturing - sections of crust between parallel fault lines drop down resulting in volcanic activity
seamount/guyots
seamount - underwater volcano that doesn’t reach the surface
guyot - seamount that has a flat top due to erosional processes
subduction zone
spot where two tectonic plates collides and one subducts beneath the other
lithosphere
crust + rigid upper section of mantle
approx 80-90km thick
