Continental drift Theory
*Wegener noticed that Africa and South America fit together the puzzle pieces
*Matching Fossils on separated coastlines
*One Large Landmass
Pangea
One large landmass
Lairasia
Two large landmass
Compositional Layers of the earth
Crust mantal and outter core.
Plate Tectonics
*earths crist and upper mantle are broken into sections called plates
*Plates move around on top of the mantle like rafts
Lithosphere
crust and part of the upper mantle
100 km thick (pretty thick)
less dense than the material below it so it floats
Asthenosphere
Plastic layer below the lithosphere=asthenosphere
plates of the lithosphere floats
2 types of plates
ocean plates=plates below the ocean
continental plates=plates below the continental
divergent boundaries
boundary between two plates that are moving apart or rifting
Types of mountains
folded fault block Volcanic
unwarped
folded mountains
form when two plates collide mainly of sedimentary rocks
Convection currents
in the Earth's mantle are what drive plate motions. Convection currents are driven by the simple fact that hot things (such as gases and liquids) rise while cool things fall.
epicenter
The point on the surface of Earth that is right above the focus of an earthquake
Earthquakes
How do we measure the intensity of an earthquake?
Mercalli Scale
V.
People feel movement.
Doors open
Pictures fall off wall. VII.
Some buildings lose bricks.
Difficulty driving.
p waves
are the 1st
s waves
waves the deadly high energy waves of an earth quake travel at 1/2 the speed of p waves