Processes Flashcards
Earth structure
-inner core: solid 5100km thick
-outer core: liquid 2900km thick
-mantle
-upper mantle made up of asthenosphere and lithosphere
-crust: 0-100km thick
What does heat from the core create?
Convection currents
Ridge push
Occurs at mid ocean ridges at constructive plate boundaries
Oceanic vs continental
- C is older
- O is more dense
-O is basaltic and C is granitic
-C is thicker
Slab pull
Occurs at subduction zones
90% of worlds earthquakes
Converging
What formed earths structure
-collisions of clouds of dust and gas
-meteorite collisions
What causes movement of tectonic plates
Convection currents
Oceanic vs continental
-180 million years old vs 3.5 billion
-continental much thicker
-oceanic more dense
-basaltic vs granitic
Divergent
Mid ocean ridges
Move away from each other
Oceanic plates
Shield volcanoes
Less powerful earthquakes
Slab pull
At subduction zones
Denser oceanic plates sink into mantle
Destructive
Convergent boundary
Move towards
Oceanic and continental
90% Earthquake
volcanoes composite
Subduction
Converging
Continental plates drag past eachother
Earthquakes no volcanoes
What is focus and epicentre
Focus= below the surface the
Epicentre= on the surface directly above focus
Body waves
Travel through earth before surface waves
-Primary waves slinky movement fastest first waves to arrive caused by compression
-Secondary waves skipping rope shake slower but cause lots of damage
Surface waves
Travel only through the crust mist destruction
-Love waves side to side fastest move ground side to side greatest damage
-Rayleigh waves up and down felt the most moves ground up and down
Ways to predicts
-monitor microquakes
-changes in ground levels
-gass measurements collection through fumaroles
-seismic activity
-cone temp
How Philippines monitor
-1984
-timely alerts
And hazard mapping and risk assessments
Land use planning
Identify most hazardous areas and avoiding to overly high density the area
