Tectonic Plates

Question 1

State the 4 layers of the earth(4 marks)

Answer 1

• crust- floats on mantle - thin - broken
• mantle - semi molten rock
• outer core- liquid
• inner core- solid

Question 2

Convection currents(5 marks)

Answer 2

•Happens in the upper mantle
•the core is hot and heats molten rock •this heated rock rises hitting the underside of the plate
• the molten rock cools further away from the core falls and rises again heating up again
• this drags the tectonic plates that is on top of the mantle with it.

Question 3

Constructive plate margins(3 marks)

Answer 3

• the plates move apart( diverge)
• causes a gap to form between the plates
• magma rises up to fill the gap created

Question 4

Destructive plate margins(4 marks)

Answer 4

• oceanic plate subducts under continental plate
• the rocks get stuck because they both are not smooth surfaces
• the friction and pressure between the plates build causing cracks (vents) where the magma rises until it’s released
• they slip past each other causing both plates to move resulting in the ground shaking

Question 5

Conservative plate margins(4 marks)

Answer 5

• plates are sliding past each other
• the rocks don’t have smooth edges so they get stuck
• friction and pressure between the plates builds until released
• they slip past each other causing both plates to move resulting in the ground shaking

Question 6

Volcanic eruptions produces( 4 marks)

Answer 6

• lava flow
• gases( sulfur, co2)
• ash - burnt rock fragments blown into the atmosphere
- can cause volcanic winters
• pyroclastic flows - hot ash, lava, and gas that can move downhill at the speed of 500 km/ h during an eruption an reach 1000*c

Question 7

Primary effects of volcanoes( 4 marks)

Answer 7

• crop and livestock deaths - lead to famine or starvation
• suffocation - ash bc of gases produced
• damaged buildings - lava and hot ash can start fires
• human deaths - large pieces of lava can burn people - pyroclastic fellows destroys everything in its path

Question 8

Secondary effects of volcanoes(7 marks)

Answer 8

• lahars ( mudflows) - destroy buildings
• flooding and tsunamis - created by a sudden displacement of the ocean - volcanoes below the ocean
• lost forests and farmland
• infrastructure damage
• volcanic winter
• economic damage
•increased soil fertility - ash is broken down

Question 9

Immediate responses to volcanic eruptions

Answer 9

• Warnings and monitoring
• temporary infrastructure
• evacuation
• aid

Question 10

Long term responses to volcanoes

Answer 10

• relocation
• improve local economy
• rebuild infrastructure

Question 11

Measuring earthquakes

Answer 11

• moment magnitude scale - measures how much energy is released
• logarithmic - goes up in tens 2 is 10x stronger then 1
• magnitude - earthquakes with a magnitude of 7 or more cause the most destruction

Question 12

Immediate responses to earthquakes( 5 marks)

Answer 12

• temporary housing
• evacuations or warnings
• temporary infrastructure
• rescue operations
• aid