volcanoes and earthquakes Flashcards
(31 cards)
What are plates created from?
Molten magma coming to the surface and they are made of all different types of rocks
What is the crust divided into?
Plates like a jigsaw puzzle
Name some features of the core?
Very dense, very hot, inner core solid, outer core liquid
Name features of the mantle?
solid, dense, heat from the core moved through it
name features of the crust?
outermost layer, low density, easily folded, variable thickness
name features of the lithosphere?
crust+ upper part of the mantle, low density, brittle, oceanic and continetal
name features of the asthenosphere?
part of the upper mantle, high density, has convection currents, when convections diverge new lithosphere when they converge lithosphere destroyed
Constructive
divergent plates=new lithosphere
e.g. N. plate & Eurasian plate
Earthquakes yes= low magnitude due to magma rising
volcanoes yes= new crust, non-explosive, lots of lava
Destructive: subduction zone
convergent plates= continental & oceanic
Nazca plate & S. American plate
earthquakes=yes really high magnitude the highest earthquakes have happened on subduction zone Chile (9.1)
volcanoes= yes extremely explosive, pyroclastic flows, lahars, little lava, ash, gas usually blast the top of the volcanoe
Destructive: island arc
convergent plates= 2 oceanic
Caribbean plate+ N. American plate
earthquakes and volcanoes are same as subduction
Destructive: collision zone
convergent plates=2 continental
Indian plate + Eurasian plate
Earthquakes yes=any magnitude but the higher they are the less frequent they are
volcanoes yes= little volcanic activity, little lava and fire fountains
conservative/transform
2 plates slide side by side
N. American + pacific plate
earthquakes yes = quite frequent can have a high magnitude though
No volcanoes
hot spots oceanic
plume of magma very close to the centre of the oceans surface
Hawaiian islands
earthquakes yes = low magnitude and infrequent due to rising magma
volcanoes yes=produces large volumes of lava, activity continuous
Hot spots continental
plume of magma rising the surface of the centre of a continental plate
yellow stone park
earthquakes yes =but infrequent and low magnitude
volcanoes yes= infrequent but are super volcanoes produce loads of different types of lava
What is a pyroclastic flow?
gas, ash large lumps of lava traveling at 200kph at
up to 100 Celsius
What are lahars?
volcanic mud flows formed when ash mixes with water moving up to 100kph
What does the sinking oceanic plate create?
ocean trench
how is an earthquake formed in a subduction zone?
two of the plates stick together then they build up pressure and then a sudden jerk happens causing an earthquake.
What is the name of where the melting occurs?
Benioff zone
what can rise through the continental crust?
plutons it is very light and full of gas
what is formed when some plutons reach the surface?
volcanoes
due to the continental plate being less dense than the oceanic plate what is formed?
The continental plate crumbles forming fold mountains
explain how fold mountains are formed
starts as a collision zone the ocean basin becomes narrower until no oceanic crust was is left and the two continental collide which = fold mountains
how are islands formed?
2 oceanic plates subducts but the non subducting plate does not fold but volcanoes occur forming a curving line of islands
