EQ1 Flashcards
Where are earthquakes found?
Near tectonic plate boundaries
70% of all earthquakes found near the pacific ring of fire
Volcanoes found?
Near tectonic plates
Tsunami cause?
Underwater earthquakes
Disrupt the seabed
Displaces water
Water spreads in multiple directions
Can also cause ground shaking
Divergent
Plates moving away from each other
Convergent
Plates moving towards each other, one sinks under the other
Oceanic vs continental crust
Oceanic crust is denser
Continental crust is less dense
Oceanic crusts sinks under the continental plate
This is known as subduction
What happens when two continental plates move away from each other?
Convection currents push them apart
Force puts pressure creating cracks
Magma rises
Explosion occurs
Leaves behind a rift valley
Example of a convergent plate boundary
The Himalayas
Indo Australian and Eurasian plates (continental)
The plates collide
They crumble
Create tectonic uplift
Himalayas are formed
What happens when an oceanic plate meets a continental plate?
Denser oceanic plate sinks
Subducts
Melts
Produces magma
Explodes
Benioff zone
Point of subduction
Constructive
Plates slide past each other
Alfred Wegners continental drift hypothesis
Assumes that all now separated countries used to be joined at one point
Paleomagnetism
The study of the polarity of the earths magnetic field, it reverses every 200,000 years
Earths internal structure
Made from metals such as iron
The metals in the core produce a magnetic field
Mantle convection
When plate moves near the asthenosphere
Convection currents cause magma to move in circles
