Hazardous Earth

• what is a tectonic hazard?

  a natural event which could cause damage to human property and the environment
• what are tectonic hazards caused by?

  convection currents causing plates to move
• what are the 4 key terms for the earths structure?

  Crust, mantle, outer core, inner core
• what is the top layer of the mantle called?

  lithosphere
• what is the lithosphere sandwiched between?

  crust & asthensophere
• who studied continental drift?


  Wegener
• what was the super continent called?

  pangaea
• what are the 4 pieces of evidence Wegner found?

  • fit of coastlines
  • fossil correlation
  • rocks and mountain correlation
  • paleoclimate data
• what is meant by paleomagnetism?

  the study of the Earth's magnetic field preserved in rocks. 
• define convection currents...

  movement of magma generated by heat in the mantle, rising and falling
• what are divergent plate boundaries also known as?

  conservative
• what are convergent boundaries also known as?

  collision / destructive
• what are transform boundaries also known as?

  conservative
• what happens at a divergent boundary?

  continental plates move apart - magma rises through
• give an example of a divergent plate boundary

  Pacific & Nazca
• what happens at a conservative boundary?

  plates slide past each other
• what happens at an oceanic/ continental convergent plate?

  oceaninc plate subducts under continental plate
• what happens at a oceanic/oceanic convergent plate boundary?

  older denser plate subducts under the other
• name an example of an oceanic/ oceanic convergent boundary

  North American / Caribbean
• name an example of a conservative boundary

  California / North American plates
• what happens at a collisional boundary?

  2 continental plates collide
• name an example of a collisional boundary

  African and Eurasian
• what is a hotspot?

  small area of earths crust where there is an unusually high amount of heat flow
• how are hotspots formed?

  strong convection currents - raise mantle plumes -plumes push upwards - becomes molten at low pressures
• where are hotspots usually located?

  no where near plate boundaries
• name 2 examples of hotspots

  Iceland

  Hawaiian islands
• define the characteristics of explosive volcanoes

  • convergent boundary
  • viscous lava
  • calderas form as sides collapse
• define the characteristics of effusive volcanoes

  • divergent boundary
  • thin/runny lava
  • lava plateau
  • shield volcano
• what is the style of eruption for explosive volcanoes?

  violent bursting of gas bubbles

  vent/ cone shatters
• what is the style of eruption for effusive volcanoes?

  gas bubbles expand freely

  limited force
• how do you measure volcanoes?

  magnitude and intensity
• what does VEI stand for?

  volcanic explosivity index
• what are the main volcanic hazards?

  Lava flows

  pyroclastic flows

  tephra

  toxic gas

  lahars

  floods

  tsunamis
• why do people live near volcanoes?

  • fertile soils
  • cheap housing
  • geothermal energy
  • tourism - income
  • uneducated
  • cannot afford anywhere else
• how do you calculate disaster risk?

  Hazard x vulnerability /capacity to cope
• what are the 3 stages of managing hazards?

  modify event

  modify vulnerability

  modify loss
• describe the disaster response curve

  stage 1 = happens before event

  stage 2 = when hazard occurs

  stage 3 = when event has happened - help is coming

  stage 4 = relief stages are on going
• what are the physical factors influencing the disaster response curve?

  • speed of event
  • magnitude
  • secondary hazard
• what are the human factors affecting disaster response curve?

  • level of monitoring
  • preparation
  • quality/ quantity of relief
• what are the three ways of measuring earthquakes?

  • richter scale
  • modified mercalli scale
  • moment magnitude scale