Plate Tectonics Flashcards
what is a volcanic eruption
escape of hot materials from under the earth’s surface
what could erupt from a volcano
ash, lava, gas, rock
what is an active volcano
volcano that could erupt at any time
what is a dormant volcano
hasn’t erupted for a considerable time but has the potential to
what is an extinct volcano
no longer able to erupt
what are the parts of a volcano
magma chamber, pipe, vent, crater
what is the vent
the part of the volcano where the lava flows through just before exiting the crater
what is the crater
the opening of the volcano where the material erupts from
what are the types of volcano
shield + composite
where do shield volcanoes occur
divergent boundaries + hotspots
where do composite volcanoes occur
convergent boundaries - subduction zones
what are the layers of the earth called
crust, mantle, outer core, inner core
what is the lithosphere
the crust and top rocky part of the mantle
describe the crust
solid rock, thinnest layer of the earth, broken into plates that float on the mantle (tectonic plates)
describe the mantle
semi-solid plastic rock, largest layer
describe the outer core
semi-liquid metals, melted from inner core’s heat
describe the inner core
solid due to pressure, metals
what is an earthquake
movement in the Earth’s crust
what is the shake that comes before a major earthquake called
Foreshock
what is the shake that comes after a major earthquake called
aftershock
where do earthquakes mainly occur
plate boundaries
how do earthquakes work
plates slip past each each other releasing energy which causes vibrations called seismic waves
what are the vibrations called
seismic waves
what scale measures the power of the earthquake
richter
what scale measures the intensity of the earthquake
mercalli
what is the focus
point where the earthquake begins
what is the epicentre
point on the surface above the focus
what is a fault
crack in the crust - pressure builds up and is released suddenly causing earthquakes
what are tectonic plates
pieces of crust
what causes plate movement
convection currents
how do convection currents work
Hot magma rises closer to the surface and as it cools it sinks back down. As it moves across, it drags the tectonic plates with it.
what is a divergent boundary AKA
constructive boundary
what directions do plates move at divergent boundary
away from each other <- ->
what happens at divergent boundaries
mid ocean ridges, rift valleys, volcanoes (plates move apart allowing magma to come up)
what is a mid ocean ridge and how are they formed
underwater mountains - plates separate, magma rises up to fill the gap, solidifying and forming new crust
what is a rift valley
a long depression in the earth’s crust
how do rift valleys form volcanoes
magma rises through the thinned crust
what are convergent boundaries AKA
destructive boundary
what directions do plates move at convergent boundary
towards each other -> <-
what happens at convergent boundaries
oceanic-oceanic: subduction = trenches + volcanoes
oceanic-continental: subduction - oceanic sinks = ocean trenches + land volcanoes
continental-continental: too light to sink in mantle = pushed up = mountains
what is subduction
when two tectonic plates collide and the less dense one sinks under the other one
what are the types of crust and which is denser
oceanic + continental / oceanic is denser but continental is more thick
what are transform boundaries
…
plates slide against each other in opposite directions | |
…
what happens at transform boundaries
friction = earthquakes
