hazards Flashcards
what is a hazard
a perceived natural event that can potentially threaten life and property
when is a natural event not a hazard
if it does affect life/ people.
what is nuees ardentes
flow of ash a from a volcano;
what are some examples of hydrological hazards
hazards caused by water. tsunamis, lahars, tropical storms, coastal flooding
glacial flooding
river flooding
what are the 3 types of hazard
geophysical, hydrological, atmospheric
what are some examples of atmospheric hazards
fires
high winds/ hurricanes
storm surges
what is a disatster
the realisation of a hazard when it causes significant impact on vulnerable population the hazard exceeds the capacity and resilience level of the population
what is meant by vulnerability
the risk of exposure to hazards combined with an inability to cope with them
what are the characteristics of oceanic crust?
oceanic crust
- dense 3.0g/cm^3
- younger and temporary <200 million years
- composed of SIMA, silicone, magnesium, basalt
-thinner by 6-10km
what are the characteristics of continental crust?
- thicker 30-70 km
- older and permanent >1500 million years
- lighter 2.6g/cm^3
- composed of mainly granate, silicon, aluminium and oxygen
what happens to an oceanic crust when it encounters a continental crust?
the oceanic crust will sink beneath the continental crust as its more dense
if the oceanic crust is more dense and therefore sinks beneath the continental crust what does this mean about the state of the continental and oceanic crust?
it means the oceanic crust is temporary as it is always changing but the continental crust is permanent
what is different about the Eurasian plate?
its made up of oceanic and continental crust
can the continental crust extend further than the margins of the landmass?
yes, for example, the under the north sea and off the west coast of the british Isles.
how are mountains formed?
when two continental plates colide with eachother at a convergent plate boundary
what landform occurs when an oceanic and a continental plate meet at a comvergent plate boundary
the oceanic plate is subducted beneath the continentl plate due to the contrasts in density. this forms a deep ocean trench.
what must be happening when new oceanic crust is being formed?
it must be being destroyed (or continental crust is buckling creating new mountains
what is the speed and frequency that tectonic plates are moving in
slow and continuous
if there is a sudden movement of the crust its detected as a what?
an earthquake
where are significant landforms such as volcanoes and deep sea trenches found?
divergent plate boundaries
what are the areas away from boundaries within plates known as?
shield lands
