A
Dense center of the earth made of solid and melted metals.
Core
Layer of the earth that surrounds the core.
Mantle
Outer layer of the Earth
Crust
Theory that the major landmasses of the Earth move
Continental Drift
Single landmass from which Alfred Wegener thought
the continents separated millions of years ago.
Pangaea
Theory that the ocean floor spreads apart as new crust is formed at mid-ocean ridges.
seafloor spreading
Theory that the Earth's surface is made of large sections of crust that move
Plate tectonics
Large section of the Earths crust that moves
plates
Circular motion of a gas or liquid as it heats.
Convection current
Mountain that develops where magma pushes up through the earths surface.
volcanos
Round opening through which magma reaches the surface of the Earth.
Vent
Small volcano with steep sides and explosive eruptions; made of ash and rock
Cinder cones
Low, broad volcano with a wide crater; formed from thin layers of lava
shield volcano
Tall volcano; formed from quiet lava flows that alternate with eruptions of ash and rock
composite volcano
folding
Break in the Earth's crust along which movement occurs
Fault
Break in the crust in which the overhanging block of rock has slid down
normal fault
Break in the crust in which the overhanging block of rock has been raised.
reverse fault
Shaking of Earths crust
Earthquake
Instrument that detects and records earthquakes
seismograph
Point inside the Earth where rock first moves starting and earthquake
focus
Scale used to measure the strength of an earthquake
richter scale
Large sea wave caused by vibrations of the Earth
Tsunami