earth Flashcards
earths formation:
1) inner core
2) outer core
3) lower mantle
4) upper mantle
5) continental/ oceanic crust
continental crust:
- forms the land
- made mostly of granite
- 30-50km thick
- less dense
oceanic crust
- under the oceans
- made of igneous rock
- 6-8km thick
- denser
asthenosphere
top layer of mantle
- very dense and thick
- partially molten and solid rock
lithosphere
upper layer of the earth cool and brittle
convection currents:
the heating, cooling, rising, sinking of the molten rock in the mantle causing movement.
convection currents causes
the movement of tectonic plates
continental drift
theory by alfred wegner
divergent plate boundaries
two plates move apart
convergent
two plates collide
conservative
two plates slide past each other
pangea
original super continent
predict volcanic eruptions
tilt meters
air craft
tilt meters
detects when a volcano swells up as it fills with magma
air craft
measure amount of gas volcano gives off
volcano case study:
sakurajima, Japan
composite volcanoes
- andesitic (high magma content)
- high pressure
- thick sticky lava
- high with steep sides
- explosive eruptions
shield volcanoes
- basaltic magma
- low pressure
- thin runny lava
- low, gently sloped sides
- gentle eruptions
eq focus:
the point of origin of a earthquake under ground
epicentre
location on the earths surface above the focus
impacts of earthquake:
- death
- damage
- tsunami
- storm surges
- blocked roads
- fire
magnitude=
how much a ground shakes (power)
seismometer
measures magnitude using the richter scale
earthquake case study:
nepal
formation of a tsunami
- plates move towards eachother
- plate moment causes earthquakes
- sea about earthquake forced upward
- sea movement causes tsunami
- tsunami waves spread quickly outward
- waves crash onto shore
