Vocabulary#14 Volcanoes

Hot spot:A very hot part of the mantle, where magma can melt through a plate moving above it.
S:As a plate moves over the hot spot,magma melts up through the crust and form volcanoes.

Vent:A central opening in a volcanic area through which magma may escape.
S:The magma escape from th vent in a volcanoe.

Lava:Magma that reaches Earth`s surface and flows out of a vent.
S:The Lava is like a magma that flows out the vent.

Crater:A cuplike hollow that forms at the top of a volcano around the vent.
S:When a volcano collapses it form a crater.

Cinder-cone volcano:A steep-sided cone that forms from explosive eruptions of hot rocks,ranging from particles to boulders.
S:Italy`s Stromboli is a cinder-cone volcano.

Shield volcano:A wide ,gently sloped cone that forms from flows of lava.
S:Hawaii`s Mauna Loa is a shield volcano.

Composite volcano:A cone formed from explosive eruptions of hot rocks followed by a flow of lava,over and over.
S:Shishaldin is a composite volcano.

Geothermal energy:Heat from below Earth`s surface.
S:Today scientist are finding ways to use geothermal energy.

Vocabulary#13 Earthquakes

Fault:A huge crack in the crust,at or below the surface,the sides of which may show evidence of motion.
S:Faults are huge cracks in the crust.

Focus:The point where an earthquake starts,where rocks begin to slide past each other.
S:The focus is usually below the surface.

Seismic wave:a vibration that spreads out away from a focus when an earthquake happens.
S:The vibrations travel through the crust in seismic waves.
 
Epicenter:The point on Earth`s surface directly above the focus.
S:The epicenter that people can feel the ground shaking.

Aftershock:The shaking of the crust after the initial shaking of an earthquake.
S:Aftershocks continue the damage of an earthquake.

Seismograph:A sensitive device that detects the shaking of the crust.
S:Seismograph is a tool to detects the shacking of the crust.

Magnitude:The amount of energy released by an earthquake.
S:The Richter Scale rates earthquakes from 1 to 10 according to magnitude.

Vocabulary#12 Moving Plates

Crust:Earth`s solid,rocky surface containing the continents and ocean floor.
S:For example when an earthquake occur the crust is moving.

Original horizontality:The idea that many kinds of rocks from in flat,horizontal layers.
S:The layers of sedimentary rock were once original horizontality.

Continental drift:The idea that a supercontinent split apart into pieces,the continents,which drifted in time to their present locations.
S:Pangaea was a supercontinent were there occur the continental drift.

Sea-floor spreading:The idea that new crust is forming at ridges in the sea floor,spreading apart the crust on either side of the ridges.
S:Scientist suggested a model to explain the huge crack called sea-floor spreading.

Magma:hot ,molten rock below Earth`s surface.
S:Magma flows through cracks,cools and hardens into new solid rock along the ridges.

Plate Tectonics:The idea that Earth`s surface is broken into plates that move.
S:Earth`s surface is broken in plates.

Mantle:Earth`s layers beneath the crust.
S:Plates move aroun in low portion of mantle.

Subduction:Where plates collide,the sliding of a denser ocean plate under another plate.
S:Subduction is a part of a cycle.