8. Tectonics Flashcards
what are the 4 layers of the earth
- crust
- mantle
- outer core
- inner core
destructive/convergent margin
where the tectonic plates are moving towards eachother and the denser plate is forced below the other one
*here volcanoes are formed and occur
constructive margin
the plates are moving apart from one another
*when this happens, the magma rises to make a new crust
collision plate boundary
where two tectonic plates are moving towards eachother
*This is how mountains occur
conservative margin
when two different plates slide past eachother in opposite directions
what is the lithosphere
crust and upper most mantle
crust
the outer layer of the earth
continental crust
thicker, older, less dense, made of granite
oceanic crust
thinner, newer, more dense, made of basalt
convection currents
heated plumes of magma which create crustal plate movement
what happens when convection currents diverge (go out)
plates move apart
where convection currents converge
plates move towards eachother
what is a plate
pieces of the earth’s crust
what is a plate boundary
the point where two tectonic plates meet
how many plates are there
7 major and 8 minor
what is a hotspot
places where the crust is very thin
where are there the most volcanoes and earthquakes?
- up across the west side of the americas
- in indonesia, australia and the islands in the pacific ocean (in between indonesia and australia)
- across the east side of asia
- Across the north of the mediterranean sea (right of Italy)
earthquake
the violent shaking of the earth’s crust
earthquake magnitude
the strength of an earthquake
earthquake intensity
the violence of earth movements produced by an earthquake
mercali scale
scale used to measure earthquake
damage
richter scale
scale used to measure earthquake
magnitude
focus
where the eqarthquake originated from
epicentre
the point on the ground surface immediately above the focus (where the earthquake originates). This is where the greatest damage usually occurs
