Tectonics Flashcards
Describe mantle convection
Heat from inner core (created by radioactive decay) moves lower mantle
Magma rises up but cools and drops back down
Moves in circles
Describe subduction
Two plates move towards each other
Denser one slides under
Melts and joins the mantle
Describe slab pull
Plates pull apart Hot magma forced up Hardens and forms new crust Cools and becomes dense Causes plate to sink and pulled down
Describe sea floor spreading
Hot magma forced up and hardens to form new crust
Earths magnetic field changes direction
Lava cools
Minerals line up with magnetic field
Where are earthquakes found?
Clustered along plate boundaries
Which plate boundary is the highest magnitude earthquakes found at?
At convergent and conservative boundaries
Where is most at risk of earthquakes?
Pacific coast of America, Japan and SE Asian Islands
Where are volcanoes found?
Clustered in narrow bands
Which plate boundary is volcanoes found at?
Convergent
Where are most volcanoes located at?
The Pacific Ring of Fire
Where are tsunami found at?
Coastal zones at risk of earthquakes
Which plate boundary are tsunami found at?
Near convergent boundaries
Where is most at risk of tsunami?
SE Asia
West/south coast of North and South America
