Please enable JavaScript.
Coggle requires JavaScript to display documents.
Under and at the Earth's surface - Coggle Diagram
Under and at the Earth's surface
Powerful forces have been at work beneath and at the Earth's surface
With the development of aerial photography,satellites and mapping the ocean floor in the past 100 years, surface patterns have revealed a great deal about where and why earthquakes and volcanoes take place
The former lie on stable sections of the Earth's crust called TECTONIC PLATES
The latter are ofthen affected by earthquakes or volcanoes along PLATE BOUNDARIES
At the centre of the Earth there is a layer of molten magma.Though this layer flow convection currents. The plates floot on the mantle. These movements give rise to earthquakes, volcanoes and fold mountains.
CONVERGING AND DIVERGING PLATES
A CRUST BIN: Oceanic crust sinks beneath continental crust (light) and melts, creating heat and pressure and magma (molten rock)
Continental plate, this part is mostly above the ocean, forming land. It is mostly made of granite, a lighter rock.
Oceanic Plate: This part is below the ocean. It is made of basalt. It is a dense, heavy rock so it sinks below the continental plates
A Crust Factory: New crust as magma cools from mantle. Sea floor spreads as plates move apart or diverge
Types of plate Boundary
Convergent boundary
MOVEMENT: Subduction
EFFECT: Destructive, old crust destroyed. A crust "bin"
RELIEF: Trench
ACTIVITY: Earthquakes and strato-volcanoes
Divergent Boundary
MOVEMENT: Spreading
EFFECT: Constructive, new crust created. A crust "factory"
RELIEF: Ridge
ACTIVITY: Eathquakes and shield volcanoes
Conservative boundary
MOVEMENT: The plates slide sideways by each other
EFFECT: Crust neither created nor destroyed
RELIEF: No major impact
ACTIVITY: Earthquakes