Convection Currents, Plate Tectonics, volcanoes and earthquakes review (8th)

volcano

A weak spot in the crust where magma has come to the surface

Forms from multiple explosive eruptions and produces a lot of lava and ash and is small with steep sides

Composite

circular depression caused by volcanic activity. the bowl-shape forms when material explodes out of the vent

crater

______________ a seismic sea wave is a ocean wave caused by a ________________

tsunami earthquake

the opening in which hot magma has been able to rise up from the magma chamber and reach the surface

vent

A pile or hill of lava,dust, ashes and rock that build up around the vent

volcanic cone

A ______________ is a ____________________ that forms when ____________ reaches the surfaces

volcano mountain magma

Rocks break apart at the __________ points along the fault and ____________ is released

weak energy

Magma ___________ because it is less dense than the solid rock around it

rises

This energy spreads outward in all directions as vibrations called _____________ __________

seismic waves

the record of the vibrations is called a ______________ and looks like jagged lines on the paper

seismogram

Seismic waves are measured and recorded by a ________________

seismograph

Andes Mountains

A large system of mountain ranges located along the Pacific coast of South America formed above the subduction zone of two convverging plates.

San Andreas Fault

A major geological fault in California formed by a sliding transform boundary.

earthquake

A shaking or sliding of the ground. It is caused by the sudden movement of masses of rock along a fault or by changes in the size and shape of masses of rock far beneath the earth's surface.

Cone shaped, tall, very steep sides eruption produces a lot cinder and ash

Cinder cone

Convergent

Equally dense plates collide and make mountains or If plates are different densities, subduction occurs, one plate slides under the other.

North American Plate

Lithospheric plate that includes almost all of North America and part of the Atlantic Ocean.

Measuring the time between the arrival of ___ and ___ waves determines the distance between the recording seismograph and the earthquake epicenter

P S

Surface waves form when ____ and ____ reach the _________. Can cause the ground to __________ making rock side to side and roll like an ocean wave

P S surface

Divergent

Plates pull apart and magma rises up.

Transform

Plates slide past each other

Alfred Wegener

Proposed the continental drift theory in the 1900s

When rock material is heated by Earth's core, will it rise or sink?

Rise

What are the 3 types of volcanoes

Shield composite cinder cone

When rock material is cool towards the top of the mantle, will it rise or sink?

Sink

Transform Boundary

The boundary between tectonic plates that are sliding past each other horizontally

Divergent Boundary

The boundary between two tectonic plates that are moving away from each other

Convergent Boundary

The boundary formed by the collision of two plates

Continental Drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

mantle

The layer of hot, solid material between Earth's crust and core. The thickest layer.

Mariana Trench

The location of the deepest trench on earth made from two oceanic crusts converging.

Convection

The movement caused within a fluid by the tendency of less dense material to rise and denser material to sink

continental crust

The portion of the earth's crust that primarily contains granite, is less dense than oceanic crust, and is 20-50 km thick

Sea-floor spreading

The process by which new oceanic crust forms as magma rises towards the surface and solidifies at divergeny boundaries.

What causes the movement of crustal plates?

The rising and sinking of material in the mantle.

Asthenosphere

The soft layer of the mantle on which the tectonic plates move

Lithosphere

The solid, outer layer of the Earth that consists of the the crust and the rigid upper part of the mantle

Plate Tectonics

The theory that the earth is broken into plates and are in motion due to convection currents in the asthenosphere (upper mantle)

Crust

The thin and solid outermost layer of the Earth above the mantle

Plate Tectonics

Theory that the Earth's crust is divided into tectonic plates which move around due to convection currents in the mantle.

convection current

a current caused by the rising of heated fluid and sinking of cooled fluid believed to drive plate movement in the mantle of the earth

mid-ocean ridge

an underwater mountain range made at divergent plate boundaries

__________________ result when forces and stresses (tension, ___________________, and shearing) along faults becomes too great as blocks of rock are pushed (compression or shearing) or _________ apart (tension)

earthquakes compression pulled

the ______________ is the point on earth's surface directly above the focus; energy that reaches the surface is ________________ at this point

epicenter greatest

trench

extremely deep areas in the ocean that are created by a subducting plate

Since earthquakes travel ____________ through the ____________ than the ______________, scientists know that the mantle is ________ than the crust

faster mantle crust denser

primary waves come ___________ secondary waves come _____________

first second

the __________ of the earthquake is the point in the crust, or ______________, where the energy is released

focus mantle

a compass needle will align with the lines of ____________ of the magnetic field

force

Volcanoes are classified by ________________

how they form

______________ occurs when soil acts more like liquid during a earthquake

liquefaction

rift valley

long, narrow depression formed at divergent boundaries

molten mixture of rock, gases and water beneath the crust

magma

_____________________ is a large _____________ of molten rock sitting underneath the _______________

magma chamber underground crust

Scientists believe that the movement of materials in the outer core of earth is what causes earth's _____________ field

magnetic

Is wide and somewhat flat and forms from a quiet eruption, lava flows quietly and far

shield

________________ is the measure of energy released during an earthquake. This is measured on the _______________ scale. the higher the number, the more ____________ released

magnitude richter energy

waves travel faster through ___________ ___________ than through _____________ ______________ material

more dense less dense

Primary waves move ______ from the earthquake focus, travel the __________ of the 3 waves, move through ___________ and ________ layers of earth, and push and pull rock creating a back-and forth motion in the direction the wave is moving (________________ wave)

out fastest solid liquid longitudinal

Secondary waves move ________ from the earthquake focus. Move _________ than primary waves, can only move through _____________ _______. Move at ________ angles to primary waves causing rocks to move up and down and side to side ( _____________ wave)

out slower solid rock right transverse

Earthquakes produce 3 types of waves

primary secondary surface

subduction

process in which two plates collide and the denser ocean plate descends below the other

the ______________ and ________________ of a seismic wave depends on the ___________ it travels. Because of the behavior of these different waves, scientists have __________ evidence for the solid inner core and ________________ outer core of the Earth

speed direction material indirect liquid

Pangea

term for the super continent which contained all the plates together

oceanic crust

thinner, more dense, younger crust making ocean floor

____________________ tells us where the epicenter is

triangulation