Plate Tectonics Flashcards
What are the 4 layers of the Earth
Crust, mantle, outer core, inner core
How thick is the mantle
2885km
How thick is the crust
Continental crust - 35-70km
Oceanic crust- 5-10km
How thick is the inner and outer core
inner- 1250km
outer- 2200km
What temperature is each of the layers
Crust- 200-400°C
Mantle- 1400-3000°C
Core- 5000-6000°C
What is the mantle made of
Magma
How do plates move
convection currents
what is a convection current
the magma closest to the core is heated up and rises, it then cools and sinks, dragging the plates above with it
what is a constructive plate boundary
two plates move apart
what is an example of a constructive plate boundary
mid-atlantic ridge
what is a destructive plate boundary
where a continental plate meets an oceanic plate + the oceanic plate is subducted under the continental plate
what mountains form at a destructive margin
fold mountains
what is a conservative plate boundary
two plates slide past each other
what is an example of a conservative plate boundary
San Andreas fault, California
what is a collision boundary
where 2 continental plates are being pulled together
which plate boundaries have volcanoes
constructive + destructive
where are there a lot of earthquakes and volcanoes
Pacific Ring of fire
what are the 3 types of volcano
Extinct- hasn’t erupted in the last 10,000 years
Active- erupted in the last 2000 years
Dormant- hasn’t erupted in the last 10,000 years but will erupt again
6 volcanic hazards
Lava flows
Volcanic dust and ash
Pyroclastic flows
Lahars (mudflows)
Gas
Acid rain
3 benefits of volcanic activity
Tourism
Geothermal energy
Mineral deposits
what is an earthquake
a tremor starting in the crust which causes shaking to be felt on the earths surface
how is an earthquake caused
when plates meet or move past each other, they often get stuck. Tension and friction build up over time and eventually the plates break free and pressure is released. This jolting force caused an earthquake
what is the magnitude of an earthquake
strength of the earthquake
What is a seismometer
the instrument used to measure earthquake magnitude
what is the Richter scale
a scale that describes the magnitude or the amount of energy released by an earthquake
where is the epicentre of an earthquake
directly above the focus
how is earthquake damage limited
Protect- overlapping bricks, cross-bracing, base isolation
Predict- seismometers, water levels rising in wells and lakes, animals acting strangely
Plan- emergency plans, earthquake drills, emergency kits
what is a tsunami
a large wave of seawater that can travel thousands of miles and is a result of an underwater earthquake
what is an example of an earthquake
Indian Ocean earthquake
date- 26 december 2004
magnitude- 9.2
length- 10 minutes
epicentre- off the west coast of Sumatra, Indonesia
people- 187,000 confirmed dead + at least 125,000 injured
66% of Sri Lanka’s fishing boats were destroyed
