Plate Boundaries, Earthquakes, Tectonics

Question 1

destructive plate boundary

Answer 1

found where continental plate meets oceanic plate. oceanic is heavier so continental sinks under. As they scrape together, friction melts the rock and escapes as lava in a violent volcanic eruption along with severe earthquakes

Question 2

conservative plate boundary

Answer 2

found when two plates slide past eachother along a fault.

No volcanoes are found but severe earthquakes occur

Question 3

constructive plate boundary

Answer 3

found where two plates move apart. as they do a gap appears and allows lava to eacape. makes gentle volcanic eruption and less violent earthquakes

Question 4

andesitic magma

Answer 4

low in temp
has more silica and dissolved gas
more likely to explode when reaches surface
very viscous (flows much slower)
creates steep sided volcanoes

Question 5

basaltic magma

Answer 5

high in temp
very low on silica
produces fluid lava with very little explosive activity
non acidic, very runny
creates gentle sides as lava flows before soldifies

Question 6

composite volcanoes

Answer 6

a tall explosive cone shaped volcano formed by layers of silica rich lava and ash

Question 7

what are shield volcanoes

Answer 7

a low flat gently sloping volcano built from many flows of liquid, low viscosity basaltic lava

Question 8

collision zone

Answer 8

fold mountains produced by upthrust
as they have an equal density, when they move together neither of them can sink and the land between them is pushed upwards to form high fold mountains.
No volcanoes, severe earthquakes

Question 9

how do tectonic plates move

Answer 9

plates float on top of soft rock below upper mantle
earth’s core heats up mantle due to radioactive day and residual heat
causes moltenn rock to rise on convection currents
when the liquid rock reaches surface it moves crust below
it then cools and forms it own crust before sinking down again

Question 10

inner core

Answer 10

6000 degrees celcius
very dense
solid ball of iron
cant melt as under enormous pressure

Question 11

outer core

Answer 11

very hot and dense (4500-5500 degrees celcius), made of liquid iron

Question 12

mantle

Answer 12

thickest layer of earth, 2900km? 1000 to 3700 degrees celcius, mantle is solid and becomes hotter and denser with depth

Question 13

crust

Answer 13

thinnest layer of the earth
oceanic is 5-8 km thick
continental - 30-40 km thick

Question 14

astenosphere

Answer 14

highly viscous region of the upper mantle of the earth

lies below the lithosphere, 80-200 km depths below surface

Question 15

lithosphere

Answer 15

rigid outer part of earth. consists of crust and upper mantle

Question 16

pyroclastic flow

Answer 16

hot chaotic mixture of rock fragments gas and ash that travels rapidly asay from a volcanic vent
can be extremely destructive, high in temp, flow along ground away from volcano at 100-700 km/h

Question 17

lahars (hazards at composite volcanoes)

Answer 17

fast-moving slurries of rock, mud and water
landslides can transform into lahars
pyroclastic flows cause lahars by melting snow and ice