Flashcards in theme two Deck (218)
cone shaped mountained formed by eruptions of lava at the surface of the earth
a depression on the surface of a volcano, formed by volcanic activity, often circular in shape with deep sides.
the natural pipe or fissure that links the magma chamber to the crater or opening on the earths surface through which lava, ash and gases flow.
magma that has escaped from beneath the earth's crust and has flowed onto the surface.
tectonic plates def
huge pieces of the earths crust that float and move on top of the much denser mantle below them
constructive/divergent plate boundary def
where two plates move apart, allowing magma to come to the surface as lava
molten rock found beneath the earths crust
magma chamber def
a large natural underground chamber of magma found within the surface of the earth beneath a volcano.
destructive/convergent plate boundary def
where two plates move towards each other
when one plate sinks below another
hot spot def
a central part of the earths crust where plumes of magma rise to the earths surface
how can magma leave a volcano on to the earths crust
very fine ash
what can volcanic eruptions be accompanied by
these are made from alternating layers of lava and ash as both come out of the vent during an eruption.
where do composite/strato volcanoes form
on destructive plate boundaries
these are made from lava. they from large volcanoes with gently sloping sides, sometimes hundreds of kilometres across before cooling and solidfying
where do shield volcanoes form
on a constructive plate boundary
these are also made from lava but the lava is acid and thicker and cools quicker. it does not flow very far before becoming solid and are steep sided and high.
one that has recently erupted and is likely to again.
one that has erupted in the last 2000 years and may erupt again. hard to predict.
long since finished erupting and has cooled down
a sudden and often violent shift in the rocks forming the earth's crust, which is felt at the surface.
fault line def
a fracture or break in the earths surface along which rocks have moved alongside each other
the location of the actual source of an earthquake below the ground surface; also called the origin
conservative platae boundary def
where two plates are sliding alongside each other
location on the surface of the earth above the focus or origin of the earthquake
powerful, devastating waves at the coast caused by an undersea earthquake or volcanic eruption that displaces the water lying above it
an instrument that meaures movement of the ground, including the seismic waves generated by earthquakes and volcanic eruptions
waves of energy that travel through the earths layers as a result of earthquakes, volcanic eruptions, magma movements and large landslides