describe and explain the distribution of earthquakes and volcanoes

•the crust is very thin - either oceanic or continental. Oceanic crust is younger, heavier, thinner and is continually being formed and destroyed 

•the crust is broken into some large and several smaller segments called tectonic plates 

•underneath the crust is the mantel. The temperatures are so high that rock exists in a semi molten state

•beneath the mantel is the outer core, where temperatures are even higher and rock exists molten

•in the centre is the inner core which is solid due to the pressure of the overlying layers

•if oceanic crusts collide the oceanic crust, being denser, will go under the continental crust (subduction) 

•deep within the Earth, heat is produced by radioactivity 

           •at the hotter areas the plastic rocks in the mantle become lighter and rise, causing

             convection currents

                     •these currents’ friction drag the rigid plates above them causing them to move 

Type of Plate Boundary	Examples	Type of Stress	Features
Destructive (Oceanic vs. Continental)	The Andes (Nazca Plate)	Compression	•earthquakes •fold mountains •volcanoes •ocean trenches •subduction
Destructive (Oceanic vs. Oceanic)	Phillipines	Compression	•earthquakes •island arcs  •volcanoes •ocean trenches •subduction
Destructive (Continental vs. Continental)	Himalayas	Compression	•earthquakes  •fold mountains
Constructive	Mid-Atlantic Ridge	Tension	•earthquakes •ocean ridges  •volcanoes
Conservative	San Andreas Fault	Shearing	•earthquakes