tectonics Flashcards
what data presentation technique would show contrasting impact of a hazard event on different countries
choropleth map
describe the outer core
a liquid layer of 2200km in thickness
which one of the earths layer has the highest density
inner core
state one primary impact of tectonic hazards
destruction of buildings
two facts about the distribution of volcanoes
- on the edge of plates = plate boundaries
- volcanoes are locates along coasts
- not evenly distributes
state two ways in which volcanic activities can endanger human life
- can damage buildings
- ash can damage aeroplane engines
- landslides can damage property
name one landform often found on destructive plate boundaries
composite volcanoes
subduction zone
fold mountains
name one landform often found on destructive plate boundaries
composite volcanoes
subduction zone
fold mountains
outline why shield volcanoes form on divergent plate boundaries
convection currents cause the plates to move apart = basaltic lave is erupted through the fissure = travels a long distance before cooling to form a volcanoes
explain one reason some earthquakes kill more people then others
- population density
- emergency service preparedness
- nature of buildings
- level of development
outline one difference between oceanic and continental crust
continental crust is thicker = oceanic thinner
continental more folded
relativste thickness of continual 50km oceanic as little as 0 km
explain one cause for the movement of tectonic plates
at convergent boundaries, gravity causes denser oceanic crust to subduct dragging the rest of the tectonic plate down
suggest two reasons for the distribution of volcanoes
clusters of volcanoes near ISLAND CHAINS occur on convergent plate boundaries = caused by oceanic crust being subjected under
volcanoes in mid ocean locations are usually divergent plate boundary as the sea floor is spreading
no volcanoes in the middle of landmasses where there is no plate boundary = limits volcanic activity
mid ocean volcanoes due to hotspots = caused by mantle plumes where the oceanic crust is very thin
explain one way people can predict volcanic activity
earthquakes = a seismometer = used to pick up vibrations in the earths crust = increase in vibrations may indicate an earthquake
eruptions = using thermal imaging techniques and satellite cameras = in order to track temp fluctuations in around the volcano = increase when an eruption is imminent
explain one cause of a tsunami
caused by earthquakes = which is caused by plate boundaries = energy
caused by landslides = causes water to be displaced generating waves
describe one way a region affected by earthquakes can prepare for this hazard
evacuating population from danger zones
suggest one reason why the number of deaths varies between earthquakes
emergency services are poorly equipped in some countries = making it difficult to access people under collapsed buildings
construction laws are less strict in some countries = leading to buildings that quickly collapse when tremors hit
describe one action that can be taken to reduce the impact of earthquakes
authorities can provide an action plan = tell emergency services what to do in event of a earthquake
construction laws can be tightened = preventing buildings from collapsing
issue early warning systems = more evacuations = out of danger zone
describe one way to reduce the impact of FUTURE earthquakes
new building laws introduced =. to ensure buildings are string enough to withstand earthquake
describe how convection currents cause plate movements
in the mantle magma circulates in huge convection currents = these currents driven by heat of core = push the plates causing them to move
magma within the mantle is heated by radioactive decay = hot magma rises = pushes against the plates causing them to move
describe the layer structure of the earths interior
lithosphere = crust
- split into tectonic plates
- oceanic and continental crust
- least dense part of the planet
asthenosphere = mantle
- partially molten
- temp range from 1000-4000
- made from peridotite
- convection currents
core
- mostly made up of iron and nickel
- divided into solid inner and liquid outer core
- densest part
- hottest part = 4000-5000 degrees
explain how volcanoes form on destructive plate boundaries
- convection currents cause plates to collide
- denser oceanic plate is pushed down into the mantle
- melts
- as the melted crust has a higher gaseous content magma rises up through crust
- magma is viscous
- forming a composite volcano
explain why earthquakes occur on conservative plate boundaries
- plates slide past each other
- friction occurs
- resulting in a build up of pressure
- release of pressure results in a earthquake
- epicentre/focus
- eg. San Andreas
explain why earthquakes happen on destructive plate margins
destructive margin where two plates collide - denser oceanic plate subducts - friction - pressure builds up and gives way - releases energy
explain how building design can help reduce impact of a earthquake
steel rod foundations - prevent collapse
cross - bracing - stops floor collapsing + walls
dampers in a roof - reducing building sway
double glaze windows = stop glass breaking
shock absorbers built into frame and foundations
explain how building design can help reduce impact of a earthquake
steel rod foundations - prevent collapse
cross - bracing - stops floor collapsing
dampers in a roof - reducing building sway
describe how people can prepare for earthquakes
- authorise action plans = tell emergency services what to do
- construction laws tightened = ensuring all buildings have STEEL SUPPORTS = enable nehme to BEND rather than crumble when shaken
describe how people can prepare for earthquakes
- authorise action plans = tell emergency services what to do
- construction laws tightened = ensuring all buildings have STEEL SUPPORTS = enable nehme to BEND rather than crumble when shaken
explain why some earthquakes are more hazardous
depth of the focus can effect strength of the earthquake = a shallow focus leads to STRONGER shock waves
emergency services are poorly equipped in some countries = harder to reach people trapped under buildings = injured may not get medical care
differences between oceanic and continental
oceanic = beneath sea vs continental = forms the land
continental crust thicker = 50km vs oceanic crust thinner = between 6-10km
continental crust has a lower density than oceanic
