Changes to Earth’s Surface Chapter 6. Prior Knowledge What are the layers of the Earth? What are the layers of the Earth? What causes Earth’s surface.

Changes to Earth’s Changes to Earth’s SurfaceSurface

Chapter 6Chapter 6

Prior KnowledgePrior Knowledge

What are the layers of the Earth?What are the layers of the Earth? What causes Earth’s surface to What causes Earth’s surface to

change?change? What causes earthquakes?What causes earthquakes? Describe a volcano and how it Describe a volcano and how it

erupts.erupts.

Lesson 1Lesson 1

How Does Earth’s How Does Earth’s Surface Change?Surface Change?

Layers of the EarthLayers of the Earth

1.1. Crust Crust (0-100 km thick) The thin (0-100 km thick) The thin outer layer of Earth, including dry outer layer of Earth, including dry land and the ocean floor.land and the ocean floor.

• This is the thinnest and least This is the thinnest and least dense layer. dense layer.

• The crust is thick under The crust is thick under continents and thinner under continents and thinner under oceans.oceans.

Layers of the EarthLayers of the Earth

2.2. MantleMantle - - The thick layer of the The thick layer of the Earth beneath the crustEarth beneath the crust

a.a. Upper part is rigid, like Earth’s Upper part is rigid, like Earth’s crust. crust.

• Underneath it is a thick zone of Underneath it is a thick zone of hot, soft rock. hot, soft rock.

Layers of the MantleLayers of the Mantleb.b. Lithosphere Lithosphere - (1.6-130 km - (1.6-130 km

thick) is the crust and the stiff thick) is the crust and the stiff upper part of the mantleupper part of the mantle

• Moho Moho - The Mohorovicic - The Mohorovicic Discontinuity is the boundary Discontinuity is the boundary between the crust and the between the crust and the mantle, where seismic waves mantle, where seismic waves change velocity.change velocity.

c.c. AsthenosphereAsthenosphere (72-250 km (72-250 km thick) is the lower part of the thick) is the lower part of the mantle which is made up of iron mantle which is made up of iron and magnesium silicate and magnesium silicate minerals. This layer is said to minerals. This layer is said to have plasticity because it is hot, have plasticity because it is hot, soft and can flow.soft and can flow.

Layers of the EarthLayers of the Earth4.4. CoreCore - - The layer of Earth extending The layer of Earth extending

from the Earth’s center to the bottom from the Earth’s center to the bottom of the mantle. It is mostly iron and of the mantle. It is mostly iron and nickel.nickel.

Outer coreOuter core (2200km thick) is made of (2200km thick) is made of very hot liquid iron and nickel. The very hot liquid iron and nickel. The movement of the outer core produces movement of the outer core produces Earth’s magnetic field.Earth’s magnetic field.

Inner coreInner core (1250km thick) is very hot but (1250km thick) is very hot but the pressure from the layers around it the pressure from the layers around it make it into a solid metal ball.make it into a solid metal ball.

Wind, Water, & Gravity Wind, Water, & Gravity Change Earth’s SurfaceChange Earth’s Surface

5.5. WeatheringWeathering - The process by which - The process by which rock is broken down into smaller rock is broken down into smaller pieces.pieces.

6.6. ErosionErosion - The removal of - The removal of transportation of weathered transportation of weathered materials.materials.

a.a. GravityGravity - is a powerful tool that causes - is a powerful tool that causes erosion. erosion.

7.7. SedimentsSediments - small pieces of rock - small pieces of rock that are weathered and eroded that are weathered and eroded and carried by wind and water. and carried by wind and water.

8.8. DepositionDeposition - is the dropping or - is the dropping or settling of eroded material and settling of eroded material and occurs very close to where occurs very close to where sediment was originally produced. sediment was originally produced.

Wind, Water, & Gravity Wind, Water, & Gravity Change Earth’s SurfaceChange Earth’s Surface

9. How do wind, water 9. How do wind, water and gravity change and gravity change Earth’s surface?Earth’s surface? They weather, erode and deposit They weather, erode and deposit

materials.materials.

Ice Changes Earth’s Ice Changes Earth’s SurfaceSurface10.10. Glaciers-Glaciers- A large sheet of moving ice A large sheet of moving ice

that stays frozen year around. that stays frozen year around.

11. 11. What are the 3 ways that glaciers What are the 3 ways that glaciers can chance the landscape? can chance the landscape?

1.1. Glaciers can carve out areas of Earth’s Glaciers can carve out areas of Earth’s surface.surface.

2.2. Deposit large piles of sediment.Deposit large piles of sediment.

3.3. Can cause the land to uplift when glaciers Can cause the land to uplift when glaciers retreat. retreat.

Impacts Change Earth’s Impacts Change Earth’s SurfaceSurface

12. 12. Meteorites-Meteorites- rocks from space rocks from space

13. 13. What causes Craters to What causes Craters to form? form?

Meteorite impacts cause Meteorite impacts cause craters to form.craters to form.

6-2 What Are Plates and 6-2 What Are Plates and How Do They Move?How Do They Move?

1. 1. Plate TectonicsPlate Tectonics -The theory -The theory that the lithosphere is divided that the lithosphere is divided into plates that are always into plates that are always moving, breaking apart, and moving, breaking apart, and colliding!colliding!

2. Most plates are made up of both 2. Most plates are made up of both oceanic and continental crust.oceanic and continental crust.

3. Look at the maps on pages 308-3. Look at the maps on pages 308-309. Compare the North 309. Compare the North American plate with the Pacific American plate with the Pacific Plate? Plate?

North American plate is smaller and North American plate is smaller and has more continental crust than has more continental crust than

the Pacific plate.the Pacific plate.

Plate BoundariesPlate Boundaries

4.4. The three main types of plate boundaries The three main types of plate boundaries are:are:

1.1. Divergent boundaryDivergent boundary -a place where 2 or -a place where 2 or more plate are moving AWAY from each other. more plate are moving AWAY from each other.

a)a) Mid-Ocean RidgeMid-Ocean Ridge - a chain of mountains beneath - a chain of mountains beneath the ocean. the ocean.

b)b) Rift Rift - highest part of the mid-ocean ridge - highest part of the mid-ocean ridge where where plates move apart. plates move apart.

c)c) Sea-floor spreadingSea-floor spreading - new lithosphere formed along - new lithosphere formed along the mid-ocean ridge from the ocean bottom cooling the mid-ocean ridge from the ocean bottom cooling and becoming rigid. and becoming rigid.

Plate BoundariesPlate Boundaries

2.2. Convergent boundaries -Convergent boundaries - Where 2 Where 2 plates move TOWARD each other. plates move TOWARD each other.

3.3. Transform Fault Boundary -Transform Fault Boundary - 2 2 plates moving PAST each other. plates moving PAST each other.

a. San Andreas fault in a. San Andreas fault in California is California is a famous transform a famous transform fault boundary fault boundary where where EarthquakesEarthquakes occur from occur from the the plates grinding past each other. plates grinding past each other.

Plate Movements change Plate Movements change Earth’s SurfaceEarth’s Surface

5.5. PangeaPangea - a supercontinent where all - a supercontinent where all of the continents were connected of the continents were connected about 220 Million years ago. about 220 Million years ago.

6.6. Why do scientists believe there was a Why do scientists believe there was a super continent that existed about super continent that existed about 220 million years ago? 220 million years ago?

PangeaPangea

6-3 What Causes 6-3 What Causes Earthquakes and Earthquakes and Volcanoes?Volcanoes?

1.1. FaultFault - a break in Earth’s crust - a break in Earth’s crust where rock on one side can where rock on one side can move in relation to rock on the move in relation to rock on the other side. other side.

2.2. EarthquakeEarthquake - A vibration in Earth's - A vibration in Earth's crust, caused by the release of crust, caused by the release of energy at a fault.energy at a fault.

3.3. FocusFocus - The point inside Earth where - The point inside Earth where an earthquake begins.an earthquake begins.

4.4. EpicenterEpicenter - The point on Earth’s - The point on Earth’s surface directly above the focus of surface directly above the focus of an earthquake.an earthquake.

5.5. P wavesP waves - Fastest waved caused by - Fastest waved caused by earthquakes, they compress and earthquakes, they compress and expand the ground as they travel.expand the ground as they travel.

6.6. S wavesS waves - Second-fastest waves caused - Second-fastest waves caused by earthquakes that move across the by earthquakes that move across the direction the p waves are traveling. direction the p waves are traveling. They can move up and down or side to They can move up and down or side to side.side.

7. What causes an 7. What causes an earthquake?earthquake?

– Pressure along faults that is Pressure along faults that is released in the form of released in the form of waves of energy cause an waves of energy cause an earthquake.earthquake.

Measuring Earthquake Measuring Earthquake Strength and DamageStrength and Damage

1.1. Seismograph readingsSeismograph readings can be used to can be used to calculate an earthquake’s strength.calculate an earthquake’s strength.

2.2. Richter scaleRichter scale - estimates the amount of - estimates the amount of energy released by an earthquake. energy released by an earthquake.

3.3. Moment Magnitude scale -Moment Magnitude scale - uses the uses the amplitude of earthquake waves to estimate amplitude of earthquake waves to estimate and earthquake’s energy and fault rupture and earthquake’s energy and fault rupture area. area.

4.4. Mercalli intensity scalesMercalli intensity scales - measure an - measure an earthquakes damage. earthquakes damage.

5.5. Tsunami Tsunami - A powerful earthquake - A powerful earthquake that occurs beneath the ocean that that occurs beneath the ocean that causes the ocean floor to rise and fall causes the ocean floor to rise and fall and produces a large destructive and produces a large destructive wave that can travel great distances.wave that can travel great distances.

6.6. What are the effects of a tsunami? What are the effects of a tsunami?

Tsunamis flood costal regions and Tsunamis flood costal regions and cause major damage and erosion. cause major damage and erosion.

VolcanoesVolcanoes

1.1. Volcanoes Volcanoes - A mountain formed - A mountain formed when molten rock is pushed to when molten rock is pushed to Earth’s surface and builds up.Earth’s surface and builds up.

2.2. What causes a volcano to form?What causes a volcano to form?

Magma that rises to Earth’s Magma that rises to Earth’s surface and erupts from a vent surface and erupts from a vent causes a volcano.causes a volcano.

3. Types of volcanoes:3. Types of volcanoes:

A.A. Shield Shield -broad, dome shaped that -broad, dome shaped that may erupt many times in a period of may erupt many times in a period of more than a million years.more than a million years.

B.B. CompositeComposite - may erupt on and off for - may erupt on and off for as long as a million years.as long as a million years.

C.C. CinderCinder - have steep sides and erupt - have steep sides and erupt for a short period of time. Most are for a short period of time. Most are less than 300m tall. less than 300m tall.

4.4. What caused the What caused the Hawaiian Islands to formHawaiian Islands to form? ?

As the Pacific plate moved over As the Pacific plate moved over a hot spot, magma erupted and a hot spot, magma erupted and formed a chain of volcanoes.formed a chain of volcanoes.