TOPIC 12 Earths Dynamic Crust and Interior

Lithosphere:Layer of rock that forms the outer shell of the earth

Crust:The upper part of the lithosphere

Small Scale Crustal ChangesLaw of original

Horizontality:Sedimentary rocks form flat horizontal layers

The Four ways that Rock Layers are Changed

1) Folding:

Compression causes layers to bend

2) Tilting:

Layer of strata get tipped

The Four ways that Rock Layers are Changed3)

Faulting:Rocks are displaced along a crack called a fault

4) Uplift:

Rock layers get pushed up many meters

Earthquakes and Igneous Activity Including Volcanoes

Earthquake:

Natural rapid shaking of the earthquake

The stored energy in the ground is released as seismic waves

Focus:

Place where the earthquake originatesEpicenter:

Place on earth’s surface directly above focus

Fault:

Plane where the rock breaks

Example

Earthquakes and Igneous Activity Including Volcanoes

Seismograph:

Instrument used to detect and measure quakes

Seismogram:

Actual recording of the quake

How it WorksAgain

3 Types of Earthquake Waves

1) P-waves (primary): Compression wave that vibrates in the same direction as particles

2) S-waves (secondary): Shear wave that moves perpendicular to the particles

3) L-waves (surface): Travel on surface and cause the damage

Properties of Seismic Waves

-P-waves are fastest and arrive at the seismograph 1st-Waves travel faster in more dense material-Waves travel faster as pressure is increased-P-waves travel through solids, liquids and gasses-S-waves only travel through solids

Location of an Epicenter

The location of any earthquake can be found by knowing the distance from the epicenter to three seismic stations.Process1) Find the time difference between P and S waves 2) Mark the time difference on scrap paper3) Use ESRT to find distance4) Repeat for 2 more seismograms

Location of an EpicenterWhat does the distance from one

seismograph tell us?The quake was somewhere on the circle

What does the distance from one seismograph tell us?

What does the distance from two seismographs tell us?Narrows it down to 2 possibilities

Exact location

Finding the Origin Time of Earthquakes

1) Use the distance to determine travel time2) Subtract travel time from arrival time

AT 10:27:35TT - 7:42

10:19:53

AT 15:26:12TT - 3:20 15:22:52

Magnitude of Earthquakes

Measure of the intensity of an earthquakeMercalli Scale:

Rates the effects of the earthquake

Richter Scale:

Measures magnitude of actual energy released

Tsunami:

Seismic sea wave triggered by a quakeHow they work

Igneous Activity and Volcanoes Volcano:

Mountain made of extrusive igneous rocksVolcanic

Eruption:Giving off of gasses lava and rock

Mount Saint HelensPyroclastic Fl

ow

Zones of Crustal ActivityRing of Fire:Area of volcanic activity surrounding the

PacificWhere are other areas of activity located?

Plate Boundaries

A Model of Earth’s Interior

Scientists use seismic waves to create a modelWhat happens to pressure as you go from crust to core?What happens to temperature as you go from crust to core?

Zones of the Earth LithosphereThinnest layer (shell on a hard boiled egg)2 Types of Crust1) Continental Crust:

Rock that makes up the continentsCompositio

n:Granite

Density:

2.7 g/cm3

2) Oceanic Crust:

Rock that makes up the ocean floorCompositio

n:Basalt

Density:

3.0 g/cm3

Zones of the Earth Moho:

The interface between lithosphere and the mantleAsthenospher

e:Upper mantle (like silly putty) able to flowMantl

e:Layer of rock between the Asthenosphere and outer core

Core:

Central part of the earth

Makes Up 80% of Earth’s Volume

2 Cores1) Outer CoreComposition

: Iron and NickelState of Matter:Liquid

2) Inner Core Composition: Iron and NickelState of Matter:Solid

NO WE ARE NOT GOING TO WATCH THE MOVIE THE CORE BECAUSE IT IS DUMB

Also Dumb!!

Plate Tectonic Theory

What is a plate?

Large section of the lithosphereThe lithosphere of the earth is made up of 12 major PlatesHow fast do these plates move? 3 to 10 cm/yr.

Evidence of Plate Tectonics

Fossils:

Land fossils match on different continentsGeolog

y:Rock types and ages match on different continentsPuzzle

:Continents fit together like a puzzle

The Driving Force Behind Plate Movements

The Three Types of Plate Boundaries1)

Divergent:Plates move away from each other

a.) Midocean ridges:

Mountain ranges in the middle of oceans

b.) Rift valleys:

Deep valleys formed from separating plates

How it happens

The Three Types of Plate Boundaries

2) Convergent:

Plates are coming together3 Varieties of ConvergenceOceanic-Oceanic:

2 oceanic plates collide-Volcanic island arcs-Destruction due to subduction

The Three Types of Plate Boundariesb) Oceanic-

Continental:Collision of oceanic and continental plates

-Mountain ranges and volcanoes-Deep sea trenches

The Three Types of Plate Boundariesc.) Continent-

Continent:2 continental plates collide

-Mountain ranges -Earthquakes

Creation and Destruction

The Three Types of Plate Boundaries3.) Transform Plate

Boundaries:Plates grind horizontally

-Deformation of rock and many quakes

San Andreas Fault

Hot Spots

Hot Spots:

Major volcanic activity in the middle of plate-Caused by concentrations of radioactive

elements-Ex: Hawaii and the GalapagosHow do they form

Effects of Plate Tectonics

Appearance of Continents:

Fit togetherFeatures of Landmasses:

Fossils on different continents, coal bed correlation, tropical fossils in NYS, marine fossils on mountainsHeat and Age

PatternsAge:

Edges of the ocean is the oldest, new material at MOR

Heat Patterns:

Rock gets cooler and denser towards the continents

Magnetic Patterns-Poles have reversed throughout

history

Sea Floor Spreading

Polarity