Tectonic activity Flashcards
Composite Volcano
- layers of ash and lava
- found at destructive or compressional boundaries
- Erupt pyroclastic flow
- Explosive eruptions
- Andesitic Magma
- High with steep sides
- High pressure
- Thick, sticky lava
Shield Volcanoes
- found at constructive or tensions boundaries
- Basaltic magma
- Low pressure
- Thin runny lava
- Frequent but gentle eruptions
- Low with gently sloping sides
Earthquake Preparation for developed countries
- earthquake drills
- earthquake proof infrastructure
- X bracing in buildings
- Underground building shock absorbers
- Damper in roof acts reducing building sway
- Cross bracing stops floor collapsing
- steel frame used because it is flexible
- double glazing to stop broken glass showering down
Conservative plate boundary
- plates slide past each other in opposite or same direction but at different speeds
- Friction is over come and one plate slips past in a sudden movement
- e.g. San Andreas Fault in California
- North american + Pacific plate
Primary impacts of volcanoes
- Deaths
- Volcanic ash released into atmosphere
- Loss of homes
List Earths Layered Structure
- Inner Core
- Outer Core
- Mantle (asthenosphere)
- Crust
Crust
- made of igneous, metamorphic + sedimentary rocks
- Oceanic + Continental
- Temp ranges from 200C to 400C
Continental crust
- 30km to 50km thick
- Made of granite
- Less dense
- Older
- Can’t be renewed and destroyed
Secondary impacts of earthquakes
- Diseases from poor sanitation
- Loss in economy
- Loss of jobs
- Tsunamis
- Rebuilding cost
Oceanic crust
- 6-8km thick
- Made of basalt, diabase and gabbro
- Denser
- Can sink
- Can be renewed and destroyed
How the core’s internal heat source generated through convection?
Radioactive decay heats up in the inner core and rises magma up to the mantle. the magma then cools causing it to go in opposite directions and fall creating a convection current. The convection current then causes the outer core to also push apart causing movement of tectonic plates.
Primary impacts of earthquakes
- Deaths
- Loss of homes
- Building damage
- Loss of water
Volcano Preparation
- Exclusion zone around the volcano
- Ready + able to evacuate residents
- Emergency kit
Earthquake Preparation for developing countries
- Emergency kits
- Hollow concrete bricks used to minimise damage if they fall.
- Steel corner pillars to provide strength and flexibility
- Cross braces or wood frame
- lightweight thatched roof
- simple steel rod foundations
- Wall made of mud and straw packed between wooden slats
Properties of the inner core
- Solid
- Radius(thickness) of 1,220km
- Made of iron-nickel
- Boundary is approximately 5400C
Convergent plate boundary(continental collision)
- Caused if two continental crusts push towards each other
- Creates mountains or earthquakes
- Nepal earthquake 2015
Upper Mantle
Inner asthenosphere: -Lubricating layer underneath lithosphere -Made of plastic flowing rocks -200km thick -Highly viscous Lithosphere: -Made of rigid rock -50 to 120km thick
Properties of the outer core
- Liquid layer
- Radius(thickness) of 3483km
- Made of iron-nickel
- Temp ranges from 2,700C to 7,730C near boundary
Divergent plate boundary
- Moving away from each other
- As tectonic plates tear apart earthquakes are caused by friction
- earthquakes are small
- when plates move apart hot and runny magma rises through gaps
Pyroclastic Flow
- hot steam, ash, rock and dust.
- roll down sides of a volcano at high speeds
- temps over 400C
Convergent plate boundary (subduction zone)
- oceanic and continental crust
- towards each other but Oceanic crust sub-ducts because more dense
- As oceanic plate sinks it melts and creates magma
- Creates volcanoes or earthquakes
Earthquake Hazards
- Buildings can be damaged by shaking
- Flow of electricity through cities can be cut
- Causes tsunamis
- Lose of economy
- Infrastructure damage
- Disease
- Looting
Properties of the mantle
- Mainly solid
- Silicate rocky shell
- Radius(thickness) of 2,886km
- Made if iron-nickel
Seismic waves
The longer seismic waves have to reach the surface the weaker the earthquake becomes
Secondary impacts of volcanoes
- Tourism attraction
- nutrients for soil
- deaths from mud flows(lahars)
