Hazourdous earth plate techtonics Flashcards
what is a divergent plate boundary
example
Plates move apart
eurasian and north american
what is a convergent plate boundary
example
when the continental and oceanic plate meet the denser oceanic plate sinks under
Nazcan under south american
what is a conservative plate boundary
example
Both plates move side by side
north american and pacific
what is a collision plate boundary
example
two continental plates collide together
eurasian and pacific
divergent plate in more detail
As the plates move apart magma is forced between the plates and this forms new oceanic plate. The earth quakes are also formed from friction between both plates.
convergent plate in more detail
When the oceanic plate sinks under the continental it melts from the heat of the mantel and the rising magma plumes escape out the crust. This forms volcanic action. It also creates earthquakes because of the rubbing friction.
conservative plate in more detail
As the two plates rub against each other the friction breaks and this causes trembles in the earth
collision plate in more detail
When both plates collide it creates trembles in the crust creating earthquakes
features of continental crust
30-50 km thick granite cannot sink less dense(2.7g/cm) cannot be renewed and destroyed older
features of oceanic crust
basalt denser(2.9g/cm) can be renewed and destroyed can sink thinner 6-8 km thick newer
def of plumes
concentrated zones of heat where the mantle is less dense and causes magma to rise to the surface
def of geothermal
heat produced from radioactive decay of elements in the core and mantel, raising the tem to 5000.c
def of convection currents
the heating, cooling, rising and sinking of the molten rock in the mantel causing it’s movement
def of magnetosphere
a huge magnetic field that surrounds the earth is made by the outer core and protects the earth from harmful radiation from space and the sun
how does the earths heat engine work
1) the radioactive decay from the inner core heats up the magma in the mantel
2) when it cools down the magma then starts to sink
3) This creates currents called convection currents
4) Because of the movement plates start to move
features of a shield volcano
basaltic lava which is runny
low pressure because of divergent plate boundary
low gentle sliding slopes
gentle eruptions
features of a composite volcano
tall
explosive as water turned into steam
high pressure because of convergent plate boundary
andesitic magma which means viscosity
what is the epicenter
the location on the earths surface above the focus
what is the focus
origin of earthquake
how are earthquakes measured
magnitude
seisometer from richter scale
(each area is 10* bigger)
how are tsunamis formed
convergent plates collide forcing ripples upwards
start of tsunami is short but builds as gets in to shallow water
when it gets to land water gets pulled back because there is less space to go
