Earth unitreview

EARTH SCIENCE REVIEW

DIFFERENCE BETWEEN CONSTRUCTIVE AND DESTRUCTIVE FORCES

Constructive forces build up the earth’s surface

Destructive wear away earth’s surface

LAYERS OF EARTH

Lithosphere- consists of crust and top of mantle Separates into plates Meets at plate boundaries

Asthenosphere- located under lithosphere; what the lithosphere glides on top of

PANGEA

All the continents were once joined together in a super continent

Continents fit together like puzzle pieces

SEA FLOOR SPREADING

Two oceanic plates moving away from each other (diverging)

The ocean floors move like conveyor belts, moving the continents away from each other

New crust is formed where the plates are spreading

SEA FLOOR SPREADING AND PLATE TECTONICS

Convection currents is the engine that drives the plates to move

TYPES OF PLATE BOUNDARIES

Convergent Divergent Transform

WHAT HAPPENS WHEN PLATES COLLIDE?

Oceanic/Oceanic- the older plate (more dense plate) will subduct

Oceanic/Continental- oceanic plate subducts because it is more dense

Continental/Continental- forms mountain ranges

DEFORMATIONS CAUSED BY STRESS

Anticlines Synclines Plateaus

TYPES OF FAULTS

Strike- Slip Fault Reverse Fault Normal Fault

FOCUS AND EPICENTER

Focus- point BENEATH Earth’s surface where rock under stress breaks to cause an earthquake

Epicenter- point on the surface directly above the focus

SEISMIC WAVES

P Waves- compress and expand the ground like an accordion (happen first)

S Waves- vibrate from side to side and up and down

Surface Waves- when waves reach the surface (cause most damage)

SCALES FOR MEASURING EARTHQUAKES

Mercalli Scale- rates earthquakes based on damage

Richter Scale Moment Magnitude scale

RISK FACTORS FOR EARTHQUAKES

Shaking Liquefaction Aftershocks Tsunamis

DEVICES TO MONITOR AND DETECT EARTHQUAKES

tiltmeter

WHERE DO VOLCANOES FORM?

Convergent boundaries Divergent boundaries Hot spots

TYPES OF VOLCANOES

Composite Shield Cinder cone

PARTS OF A VOLCANO

ACTIVITY OF VOLCANOES

Active Dormant Extinct

MAGMA AND LAVA

Magma is molten rock under the ground When magma reaches the Earth’s surface, it

is called lava

SILICA AND MAGMA’S VISCOSITY

Silica determines viscosity The more silica, the more viscous a

substance is More silica magma is light colored and is too

sticky to flow far Less silica magma flows readily and produces

dark colored lava

HOW DOES TRAPPED GAS EFFECT A VOLCANO’S ERUPTION?

As magma rises toward the surface, the pressure decreases and the dissolved gases begin to expand and exert an enormous force