Geology Flashcards
Seismic waves
Waves produced by earthquake
Mechanical layers of the earth
Atmosphere Hydrosphere Crust Mantle Outer core Inner core
Compositional layers
Crust
Mantle
Outer core
Inner core
Atmosphere
Blanket of gas surrounding earth to height of 145km. Mostly made up of nitrogen and oxygen
Hydrosphere
Water on earth’s surface
Crust
Included landforms, rocks and soils. Varies from thickness 5-70km. Thinness can be compared to as the skin of apple
Mantle
Partially molten rock. Temp from 500-2000 degrees celcuis. About 2900km thick
Outer core
Molten iron and nickel. Temp between 4000-6000 degrees celcius. About 2300km thick
Inner core
Mostly iron. Solid due to extreme pressure. Temp up to 7000 degrees celcius. About 1200km thick
Continental drift
Theory proposing continents float or drift on denser materials. Continents break apart and rejoin in process
Pangae
Name of the continent when all continents were together.
Panthalasia
Ocean that was surrounding pangae
Continental crust
Makes up continents. 30-70km thick
Oceanic crust
Under oceans
About 6 km thick
Subduction
Oceanic crust pushed under continental crust
Subduction zone
Zone where old oceanic crust pushed downwards towards mantle to form magma.
Destructive plate boundaries
Boundary between converging plates
Constructive plate boundaries
Boundary between divergent plates
Ocean ridges
Plate boundaries underwater. New oceanic crust being created at oceanic plate boundary
Conservative plate boundaries
Boundary between transform plates
Converging plates
Plates moving towards from each other
Divergent plates
Plates moving away from each other
Transform plates
Plates that slip and slide against each other
Hotspots
Where volcanoes form within plates.
Folding
Process of folding and bending of layers of rock
Anticlines
Folds that bend upwards
Synclines
Folds that bend downwards
Fault
When movement occurs along a crack on rock
Rift valleys
Formed when a block of crust have dropped down between faults
Horst
Block of crust pushed upwards from force created by rift valley
Slip fault
If movement along a fault is sideways
4 causes of earthquakes
Movements 700km under surface
Pushing against each other in subduction zones
Spreading apart at ocean ridges
Plates slipping and sliding each other
Epicentre
Point directly above where movement started under surface
Focus
Point which earthquake begins
Triangulation
Process using 3 different seismic stations to find epicentre
Seismograph
Used to record movement in the earth
Richer scale
Most used method of measuring strength of earthquakes. Is the measure of amount of energy released by earthquakes
Microquake
Earthquake measuring 2.0 or less on ritcher scale
3 types of waves
P-waves
S-waves
L-waves
P-waves
Fastest seismic wave
Travels in compression waves
Is a body wave
S-waves
Travel in transversal waves
Body wave
L-wave
Is a surface wave
Slowest seismic wave
Body wave
Seismic wave that travels through body of earth
Surface wave
Seismic wave that travels on surface.
Responsible for most of damage created by earthquakes
Seismologists
Scientists who measure earthquakes
Tsunami
Giant wave created by an earthquake underwater
DART
(Deep-ocean, Assessment and Reporting of Tsunamis)
Early warning system for tsunamis
Sudden rises detected by buoys and sent to tsunami warning centres