Volcanoes And Earthquakes Flashcards
At what plate margins are volcanoes found?
Destructive and constructive.
How are volcanoes formed at destructive plate margins?
The oceanic plate is destroyed in the mantle,
A pool of magma forms,
The magma rises through cracks called vents,
The magma (now lava) erupts onto the surface where it forms a volcano.
How are volcanoes formed at constructive plate margins?
The magma rises up into the gap created by the plates, forming a volcano.
Apart from at constructive and destructive plate margins, how else do volcanoes form?
Volcanoes can form over very hot areas of the mantle, called hotspots, eg Hawaii.
How do earthquakes occur at destructive plate margins?
Tension builds up when one plate gets stuck when moving into the mantle.
How do earthquakes occur at constructive plate margins?
Tension builds up along cracks in the plate as they move away from each other.
How do earthquakes occur at conservative plate margins?
Tension builds up when plates get stuck whilst moving past each other.
What is the focus?
The point in the Earth where the earthquake originated.
What is the epicentre?
The point on the Earth’s surface, directly above the focus.
What scale is used the measure the magnitude of earthquakes?
The Richter scale.
