Earths Forces Flashcards
What is the core
The centre of the earth, made up of a solid iron inner core surrounded by a liquid outer core. 6,400km deep. Up to 6000*c
What is the mantle
The liquid layer surrounding the core 3000km deep
What is the crust
The solid outer layer of the earth 30-50km deep
What is the continental crust
Older, thicker but less dense (lighter) crust
What is the oceanic crust
Younger, thinner but more dense (heavier) crust
What are convection currents
Currents of rock in the mantle that rise up from the core, spread outwards and sink back down again
What are constructive boundaries
Where two plates are pulled apart, allowing new oceanic crust to be formed in the gap
What are destructive boundaries
Where oceanic crust meet continental crust. The oceanic crust is subducted under the continental crust. Heat from the mantle, and friction with the continental crust, cause it to melt. The melted rock can then force a way to the surface and erupt
What are conservative boundaries
Where two plates (of any type) move side by side. Crust is neither created or destroyed
What are collision boundaries
Where continental crust meets continental crust. Both plates buckle and fold upwards
What are the effects of volcanic eruptions
Pyroclastic flow and lahars (Hot mudflows) can kill people, lava flows destroyed crops and bury towns and villages, Ash can ruin crops and cause roofs to collapse, volcanic gas causes acid rain which kills trees and plants, dust can cause plants to crash
What are the effects of earthquakes
Buildings and bridges can collapse, gas and water pipes can burst, electricity wires get torn down, landslides can block roads
How can we reduce the effects of earthquakes
Earthquake drills e.g. in school, emergency grab bags, earthquake proof buildings
