LAYERS OF THE EARTH

The Earth is made up of 3 main layers:

CRUST MANTLE CORE

Thinnest layer of the Earth that ranges from only 2 miles in some areas of the ocean floor to 75 miles deep under mountains

Made up of large amounts of silicon and aluminum

Two types of crust: oceanic crust and continental crust

Composed of plates on which the continents and oceans rest

CRUST

Solid but capable of flow (like hot asphalt or fudge)

Thickest layer of the Earth (making up 70% of the Earth’s mass)

The hot material (magma) in the mantle rises to the top of the mantle, cools, then sinks, reheats, and rises again. These convection currents cause changes in the Earth’s surface

MANTLE

Molten (liquid) metal that is about 4,700°C (8,500°F)

Located about 1,800 miles beneath the crust and is about 1,400 miles thick

Composed of the melted metals nickel and iron

OUTER CORE

Solid sphere composed mostly of iron

It is believed to be as hot as 6,650°C (12,000°F)

Heat in the core is probably generated by the radioactive decay of uranium and other elements

It is solid because of the pressure from the outer core, mantle, and crust compressing it tremendously

INNER CORE

(crust and upper mantle) is divided into separate plates which move very slowly in response to the “convecting” part of the mantle.

LITHOSPHERE

The Earth’s crust and upper mantle are broken into sections called plates

Plates move around on top of the mantle like rafts.

Plate Tectonics

Tectonic is a term derived from a Greek word _____ ,

tekton

what does tekton mean?

“carpenter” or “builder”.

The plastic layer below the lithosphere = _________

The plates of the lithosphere float on the _______

Asthenosphere

what plates is below the oceans

ocean plates

what plates is below the continents

continental plates

Boundary between two plates that are moving apart or rifting

RIFTING causes SEAFLOOR SPREADING

Divergent Boundaries

Features of Divergent Boundaries

Mid-ocean ridges

rift valleys

fissure volcanoes

Boundaries between two plates that are colliding

Convergent Boundaries

it occur at subduction zones
it collides ocean plate to continental plate

VOLCANOES

The less dense plate slides under the more dense plate creating a subduction zone called a _________

it collides ocean plates to ocean plates

TRENCH

Boundary between two plates that are sliding past each other

EARTHQUAKES along faults

Transform Fault Boundaries

Hot magma in the Earth moves toward the surface, cools, then sinks again.

Creates ____________ beneath the plates that cause the plates to move.

convection currents

The shaking or trembling caused by the sudden release of energy

Usually associated with faulting or breaking of rocks

Continuing adjustment of position results in aftershocks

Earthquakes

earthquakes occur

Fractures, faults

and seismic waves

Where do earthquakes occur?

oceanic and continental plate

Vibration of the Earth produced by the rapid release of energy

Earthquakes

Energy moving outward from the focus of an earthquake

Seismic waves

location of initial slip on the fault; where the earthquake origins

Focus

spot on Earth’s surface directly above the focus

Epicenter

instruments that detect seismic waves

Seismometers

Record intensity, height

and amplitude of seismic

waves

Seismographs

it is a vent or 'chimney' that connects molten rock (magma) from within the Earth’s crust to the Earth's surface.

The ______ includes the surrounding cone of erupted material.

volcano

A volcano that erupts often

active

When a volcano is -______, or sleeping, it has not

erupted for a long time – but it might in the future.

dormant

A volcano is ______, or dead, when it hasn’t erupted

for at least 100,000 years.

extinct

This is where all the active volcanoes are

pacific ring of fire