Earth Science Notes.ppt

Earth Science

Earth Formation Revisited

• Earth formed 4.6 Billion years ago

• Impact theory states that mars sized

object hit Earth 50 mya after that.

• 4.6 Billion Years Ago.

Earth Forms

• 3.5 Billion Years Ago.

Life Begins

• 2.5 Billion Years Ago.

Photosynthesis

• 200 Million Years Ago.

Pangea breaks up.

• 65 Million Years Ago.

Dinosaurs die off

• 200,000 Years Ago.

Earth: Four Spheres

• Hydrosphere: The water on Earth

• Atmosphere: The gaseous envelope

surrounding Earth

• Biosphere: All life on Earth

•

_{Geosphere: land and rocks}

Geosphere Terminology

• Core: inner core=solid; outer core=liquid

• Mantle: “plastic” in texture

• Crust: lighter, rocky, thinner outer layer

• Lithosphere: crust + upper mantle

– Two type of lithosphere: Oceanic and Continental

– Lithospheric plates “Float” atop the Astenosphere

Deepest hole ever drilled

• Kola Superdeep

Borehole

• 12,261 meters

(40,230 ft) (7.5 mi)

deep in 1989

Determining the layers of the Earth

using Earthquake waves

• All waves bend easily

• Some bounce back as

the type of rock

changes.

• These create areas on

the surface where the

waves are felt differently

• Mapping these out

helps us determine the

interior of the earth

Seismic Waves Visualization

#1 SLINKY INQUIRY—S vs. P

#2 ONLINE ANIMATION

Earth Science

Plate Boundaries

The three types of lithospheric plate

boundaries:

1. Divergent

2. Convergent

3. Transform

1. Divergent Plate boundaries

• Divergent boundaries occur when 2 plates move

apart

, resulting in an upwelling of material from

the mantle.

• Sometimes called

constructive

plate margins

because new lithosphere is being produced

• Mid-ocean ridges (O-O) and Rift Valleys (C-C)

form

2. Convergent boundaries

2. Convergent Boundaries

• Convergent boundaries are destructive

because plate margins produce trenches,

volcanoes and mountain ranges

• Older portions of oceanic plates return to

the mantle here

• Three types of convergent boundaries:

1. Oceanic-Oceanic

Oceanic-

Oceanic Convergent

• Two oceanic slabs converge and one

descends beneath other one

Continent-Continent C

onvergent

• Two continents come closer together to

produce mountains

Oceanic-Continental

• Denser oceanic slab sinks into the

asthenosphere underneath the less dense

continental lithosphere

• Descending plate reaches 100-150 km

some of the asthenosphere melts,

3. Transform boundaries

• Two plates grind past each other with no

construction or destruction of lithosphere

• Fault lines and earthquakes are

http://www.pbs.org/wgbh/aso/tryit/tectonics/

shockwave.html

Plate

Boundary

Type

Plate

Movement

Crust type(s)

Sea Floor

(Created or

Destroyed)

Tectonic

Process

Associated Landforms

Divergent

Apart

Ocean-Ocean

_Created

Seafloor

Spreading

Mid-Ocean Ridges,

Volcanoes, Hot Spots

(ex. Mid-Atlantic Ridge)

Continental-Continental

Created

Rifting

Rift Valleys, Sea Basins

(ex. Great African Rift Valley)

Convergent

Together

Ocean-Ocean

Destroyed

Subduction

Deep Ocean Trenches,

Island Chains (Arcs)

(ex. Java Islands; Mariana Trench near Japan)

Continental-Continental

N/A

Collision

(ex. Himalaya Mountains in Asia)

Mountains

Ocean-Continental

Destroyed

Subduction

Volcanic Arcs; Mountains

(ex. Cascade Mountains in Washington State)

Transform

Side to

Side

Ocean-Ocean, Continental-Continental, Ocean-Continental

Earth Science

Continental Drift Hypothesis

The theory of Plate tectonics began with

Continental Drift Evidence

Evidence of the Continental Drift Hypothesis:

1. Continental puzzle: the continents “fit” together

2. Matching fossils on different continents

3. Matching rock types and structures:

For Example, the Appalachian mountains end in Canada and begin

again in British Isles and Scandinavia

4. Ancient climates:

Objections to Continental Drift

• No feasible mechanism described for continental

movement by Wegener

• Wegener suggested tidal influence from moon

was strong enough to move continents….not

correct

• Also suggested that larger continents broke

through oceanic crust like an “ice-breaker” cuts

through ice…not correct

Plate Tectonics Theory (1967)

Plate Tectonics Theory:

• The uppermost mantle and the crust behaves like a

strong, rigid layer known as lithosphere, riding on top of

the weaker asthenosphere

• Lithosphere divided into plates which move and

continually change shape & size

• Plate movement is driven by convection currents in the

mantle. The heat source is from radioactive isotope

decay.

• Density Demonstration:

#2 Convection of Air in Room

http://www.echalk.co.uk/Science/physics/convection/convection.html

#3 Lava Lamp Convection

http://www.youtube.com/watch?v=gTEA-nzW-0Q

#1 Convection in the Mantle

Sea-Floor Spreading

Sea-Floor Spreading (Harry Hess 1962):

• Mid-ocean ridges are the places where

new ocean floor forms, moving slowly

outward until it sinks back into the mantle

beneath deep-ocean trenches at

Evidence for Sea Floor spreading

Evidence for Sea Floor

spreading-1. Magnetic stripes in ocean floor rock: Basalt has

lots of magnetite in it which records the pole

location of the Earth when it cools.

– Normal polarity--earth magnetic field lines up in same

direction as present magnetic field

– Reverse polarity--magnetic field lines up in opposite

direction

Seafloor spreading activity

• Work as table partners

• Push two books together

• Take two pieces of paper and slip them in the gap between the two

books so that most of the paper is under the books with it coming

out and on top of the book

• Have each person on either side of the book hold the same color

marker

• Very slowly pull the paper away from each side at the same rate

• Start coloring the paper over the gap of the book when I say we are

having normal magnetic pole position

Seafloor spreading activity

Once we are done making the new seafloor, label

the following on your sheets of paper:

•Normal pole position

•Reverse pole position

•Oldest basaltic rock

In Summary:

Earth Science

Definition of an Earthquake

• An earthquake is the sudden, sometimes

violent movement of the earth's surface

from the release of energy in the Earth's

crust.

•

_{Elastic Rebound Theory}

_{: energy (kinetic)}

is released from Earthquakes in waves

How Are Earthquakes

Measured?

• A

seismometer

is an

instrument that senses

the earth's motion;

• A

seismograph

Earthquake (Seismic) Waves

Body Waves:

–P Waves

–S Waves

Surface Waves:

-L/R Waves

P Waves (primary waves)

P Waves (primary waves):

• Compressional waves

• Move twice as fast as S waves and are usually

felt first as a kind of boom that rattles the

windows.

• Can move through solids and liquids

S Waves (secondary waves)

S Waves (secondary waves):

• Transverse waves: side to side or up and down

• Move slower than P waves

Additional Resources

• http://www.classzone.com/books/

earth_science/terc/content/visualizations/

es1009/es1009page01.cfm

Earthquake Damage

Huaraz,

Peru

Fault Plane

Types of Faults

1.Normal:

Hanging wall moves

down relative to foot wall

2.Reverse:

Hanging wall moves

up relative to foot

wall

3.Strike/Slip:

Side to side

movement

Ways to measure Earthquakes

1. Magnitude: measures the size of

seismic waves or amount of

energy released at the source

2. Intensity: measures how much

damage occurs at a given

There are over a million quakes annually

that occur all over the Earth, including those

too small to be felt..

Description

Magnitude

Frequency per

year

Great

8.0+

1

Major

7.0-7.9

18

Large (destructive)

6.0-6.9

120

Moderate

(damaging)

5.0-5.9

1,000

Minor (damage

slight)

4.0-4.0

6,000

Generally felt

3.0-3.9

49,000

Potentially

perceptible

2.0-2.9

300,000

Imperceptible

less than

Magnitude

Intensity

Description

1.0

–

3.0

I

I.

Not felt except by a very few under especially favorable conditions

3.0

–

3.9

II

–

III

II.

Felt only by a few persons at rest, especially on upper floors of buildings.

III.

Felt quite noticeably by persons indoors, especially on upper floors of buildings Many people do not recognize it as an earthquake. Standing motorcars may rock slightly. Vibrations similar to the passing of a truck. Duration estimated. Hanging objects swing.

4.0

–

4.9

IV

–

V

IV.

Felt indoors by many, outdoors by few during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motorcars rocked noticeably.

V.

Felt by nearly everyone; many awakened. Some dishes, windows broken, Unstable objects overturned. Pendulum clocks may stop, start, change rate. Liquids disturbed, some spilled. Small, unstable objects displaced or upset.

5.0

–

5.9

VI

–

VII

VI

.

Felt by all, many frightened and run outdoors. People walk unsteadily. Windows, dishes, glassware broken; knick-knacks, books, etc. off shelves. Pictures fall off walls. Small bells (church, school) ring. Some heavy furniture moved; a few instances of fallen plaster. Damage slight.

VII.

Difficult to stand. Noticed by drivers of motorcars. Hanging objects quiver. Fall of plaster, loose bricks, stones, tiles, cornices, also un-braced parapets and architectural ornaments. Waves on ponds, water turbid with much. Large bells ring. Concrete irrigation ditches damaged. Damage negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built or badly designed structures; some chimneys broken.

6.0

–

6.9

VIII

–

IX

VIII.

Steering of motorcars affected. Damage slight in specially designed structures; considerable damage in ordinary substantial building with partial collapse. Damage great in poorly built structures. Fall of chimneys, factory stacks, columns, monuments, towers, elevated tanks and walls. Change in flow or temperature of springs and wells. Branches broken from trees. Heavy furniture overturned.

IX.

General panic. Serious damage to reservoirs. Underground pipes broken. Damage considerable in specially designed structures; will-designed frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations.

7.0 and higher

X

or higher

X.

Serious damage to dams, dikes, embankments. Water thrown on banks of canals, rivers, lakes, etc. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations. Rails bent.

XI.

Few, if any (masonry) structures remain standing. Bridges destroyed. Underground pipelines completely out of service. Rails bent greatly.

Where Did the Largest Known

Earthquake Occur?

• A magnitude 9.5 earthquake in Chile in

1960 was the largest known earthquake

and resulted in over 6,000 deaths. It

Earth Science

Volcanoes

Volcanoes happen:

1. At

Divergent

plate boundaries

2. At

Convergent

plate boundaries

3.

Intraplate

(within a lithospheric plate)

Divergent Volcanism

Divergent Volcanism

: volcanic activity

occurs where plates are pushed apart by

rising and then cooling magma

Convergent Volcanism

Convergent Volcanism:

• Sinking slabs of oceanic crust subduct into

mantle and increasing temperature and

pressure creates magma that rises.

Intraplate volcanism

Intraplate volcanism

: occurs where a mass

of hotter-than-normal mantle or “mantle plume”

rises towards surface, creating a “hot spot”

Magma

Magma:

• Molten rock that forms in the crust and upper

mantle when solid rock partially melts

Factors Affecting Eruptions

Whether an eruption is explosive or quiet depends

upon these characteristics of the magma:

1. Viscosity is a substance’s resistance to flow

e.g. maple syrup is more “viscous” than water

• More viscous, more explosive eruption

2. Dissolved Gases escape easily or explode

to the surface when they get trapped

Viscosity Demonstration:

Types of Volcanoes

1. Shield Volcanoes

are produced by the

accumulation of fluid basaltic lavas and

produce gentle eruptions

2. Cinder Cones

are steep-sided volcanoes

formed by ash and cinders

3. Composite Volcanoes

(Stratovolcanoes)

What kind is this?

• What is the trend in size of the islands?

• Knowing what you know about erosion

• What is a logical hypothesis for how the

Characteristics of Lava Inquiry

•

Task:

your group will design and conduct an

experiment to test the viscosity characteristics of

three liquids: water, dish soap, and pancake

syrup.

• You will work in teams of 4 but will each

individually have a lab sheet that includes your

research question, independent variable,

dependant variable, hypothesis, materials used

list, experimental design, data table, and

Characteristics of Magma Inquiry

•

Materials available:

• The three liquids (mandatory)

• Laminated graph paper

• Test tubes

• Plastic syringes (to measure quantity of liquids)

• A timer (using your phone)

• Rulers

• Hot plate

• Freezer

• Paper Clips

Earth Science

Plate Tectonics Jeopardy

http://daphne.meccahosting.com/