Earthquakes: What are they and what causes them to happen? Mrs. Hornsby’s Fifth Grade Class.

Earthquakes: What are they and what Earthquakes: What are they and what causes them to happen? causes them to happen?

Mrs. Hornsby’s Fifth Grade ClassMrs. Hornsby’s Fifth Grade Class

Table of ContentsTable of Contents Georgia Performance Standards Georgia Performance Standards What is an Earthquake?What is an Earthquake? What are Earth’s layers? What are Earth’s layers? What are Plate Tectonics?What are Plate Tectonics? What Happens When Plates Move? What Happens When Plates Move? Types of Plate BoundariesTypes of Plate Boundaries

The Theory of Continental DriftThe Theory of Continental Drift What is a Fault? What is a Fault? What Happens when an Earthquake Starts?What Happens when an Earthquake Starts? How are Earthquakes Measured?How are Earthquakes Measured?

The Richter Magnitude Scale The Richter Magnitude Scale How Long Does an Earthquake Last?How Long Does an Earthquake Last? How Many Earthquakes Happen Each Year? How Many Earthquakes Happen Each Year? Where Do Earthquakes Occur Most Often in the United Where Do Earthquakes Occur Most Often in the United

States?States? The 25 Largest Earthquakes in the United States The 25 Largest Earthquakes in the United States Famous Earthquakes Around the World Famous Earthquakes Around the World Photos of Earthquake Damage Photos of Earthquake Damage What Have You Learned?What Have You Learned? References References

GeorgiaGeorgia Performance Performance StandardsStandards

S5Cs4:S5Cs4: Students will use ideas of system, model, change, and Students will use ideas of system, model, change, and scale in exploring scientific and technological matters.scale in exploring scientific and technological matters.

S5E1:S5E1: Students will identify surface features of the Earth caused Students will identify surface features of the Earth caused by constructive and destructive processes. by constructive and destructive processes.

S5P1:S5P1: Students will verify that an object is the sum of its parts. Students will verify that an object is the sum of its parts.

M5D1:M5D1: Students will analyze graphs. Students will analyze graphs.

M5N5:M5N5: Students will understand the meaning of percentage Students will understand the meaning of percentage

What is an Earthquake?What is an Earthquake?

An earthquake is a shaking of the ground caused An earthquake is a shaking of the ground caused by a sudden release of energy in the Earth’s by a sudden release of energy in the Earth’s crust. More than a million of them occur each crust. More than a million of them occur each year! However, most are too small to be felt or to year! However, most are too small to be felt or to cause damage. Click the picture below to watch a cause damage. Click the picture below to watch a video about earthquakes.video about earthquakes.

What are Earth’s Layers?What are Earth’s Layers? The Earth’s The Earth’s crustcrust is the outer is the outer

layer and is made of rock. It is layer and is made of rock. It is very thin compared to the very thin compared to the other layers. other layers.

The The mantlemantle is the very hot is the very hot layer of rock beneath the layer of rock beneath the crust. No one has ever been to crust. No one has ever been to the mantle, but rock from the the mantle, but rock from the mantle sometimes reaches the mantle sometimes reaches the Earth’s surface through Earth’s surface through volcanoes. volcanoes.

The The outer coreouter core is made of is made of liquid, or liquid, or moltenmolten iron. iron.

The The inner coreinner core is made of solid is made of solid iron. Even though the core is iron. Even though the core is the hottest layer, great the hottest layer, great pressure at the center of the pressure at the center of the Earth keeps the inner core Earth keeps the inner core solid. solid.

Inner Core

Outer core

Mantle Crust

What are Plate What are Plate Tectonics?Tectonics?

Earth’s surface is made up Earth’s surface is made up of many plates that float of many plates that float on the soft rock of the on the soft rock of the mantle. As the mantle mantle. As the mantle moves, the plates also moves, the plates also move. move.

Plates move only a few Plates move only a few centimeters each year. centimeters each year.

When one plate moves, it When one plate moves, it affects the other plates. affects the other plates.

As plates move around, As plates move around, they cause great changes they cause great changes in the Earth’s surface, in the Earth’s surface, such as mountains, such as mountains, valleys, volcanoes, and valleys, volcanoes, and earthquakes! earthquakes!

What Happens When Plates What Happens When Plates Move?Move?

Plate Tectonics

Convergent Plate Boundaries

Divergent Plate Boundaries

Transform Boundaries

plates crunch together and release

energy

mountains develop, volcanoes erupt, and

earthquakes can happen

plates pull apart andnew crust is formed

valleys and volcanoesdevelop, earthquakes

can occur

plates slide past each other

Lots of earthquakes!

Types of BoundariesTypes of Boundaries

Wegener’s Theory of Continental Drift

What is a Fault?What is a Fault? Many earthquakes occur along Many earthquakes occur along

faults in the Earth’s crust. A faults in the Earth’s crust. A faultfault is a place where pieces of the is a place where pieces of the plates move. plates move.

A A normal faultnormal fault is where tension is where tension weakens the crust until the rock weakens the crust until the rock fractures, and one rock moves fractures, and one rock moves downward from another. This downward from another. This occurs when two plates are pulling occurs when two plates are pulling apart, as in a divergent boundary. apart, as in a divergent boundary.

A strike-slip fault is where two A strike-slip fault is where two blocks of rock are moving past blocks of rock are moving past each other horizontally, as in a each other horizontally, as in a transform boundary. The famous transform boundary. The famous San Andreas Fault San Andreas Fault is a strike-slip fault. is a strike-slip fault.

A Reverse fault is where a fault A Reverse fault is where a fault block is forced upward, usually block is forced upward, usually during a collision with another during a collision with another block, as in a convergent block, as in a convergent boundary. boundary.

What Happens When an What Happens When an Earthquake Starts?Earthquake Starts?

The sudden release of energy from The sudden release of energy from an earthquake sends out several an earthquake sends out several different shaking movements, or different shaking movements, or seismic wavesseismic waves..

Surface wavesSurface waves are ripples of energy are ripples of energy that spread outward when rocks slip that spread outward when rocks slip past each other along a fault, just past each other along a fault, just like throwing a stone into a calm like throwing a stone into a calm pond. pond.

Body wavesBody waves are seismic waves that are seismic waves that travel through material rather than travel through material rather than over its surface. There are two types over its surface. There are two types of body waves: of body waves: P-wavesP-waves and and S-S-waveswaves. .

The P-wave is also known as the The P-wave is also known as the sound wave. It travels through the sound wave. It travels through the interior of the Earth rather than interior of the Earth rather than over the surface as a series of over the surface as a series of squeezes and stretches. P-waves squeezes and stretches. P-waves reach everywhere around the Earth reach everywhere around the Earth after about 20 minutes. after about 20 minutes.

The S-wave, or shear wave, The S-wave, or shear wave, produces a shaking motion, like if produces a shaking motion, like if you tied a rope to a poll and shook you tied a rope to a poll and shook the other end side to side. S-waves the other end side to side. S-waves can only travel in solid material. can only travel in solid material.

How are Earthquakes How are Earthquakes Measured?Measured?

Earthquakes are measured by Earthquakes are measured by instruments called instruments called seismographsseismographs. It . It has a base that sets firmly in the has a base that sets firmly in the ground, and a heavy weight that ground, and a heavy weight that hangs free. When an earthquake hangs free. When an earthquake causes the ground to shake, the causes the ground to shake, the base of the seismograph shakes base of the seismograph shakes too, but the heavy weight does not. too, but the heavy weight does not. The spring that it is hanging from The spring that it is hanging from absorbs all the movement. The absorbs all the movement. The seismograph records the difference seismograph records the difference in position between the shaking in position between the shaking part and the motionless part.part and the motionless part.

The recording is called a The recording is called a seismogramseismogram. It is used to determine . It is used to determine how large the earthquake was. A how large the earthquake was. A short wiggly line that wiggles very short wiggly line that wiggles very little means a small earthquake. A little means a small earthquake. A long wiggly line that wiggles a lot long wiggly line that wiggles a lot means a large earthquake. means a large earthquake.

The Richter Magnitude ScaleThe Richter Magnitude Scale

DescriptionDescriptionRichter Richter

MagnitudesMagnitudes Earthquake EffectsEarthquake Effects

MicroMicro Less than 2.0Less than 2.0 Microearthquakes, not felt.Microearthquakes, not felt.

Very MinorVery Minor 2.0-2.92.0-2.9 Usually not felt, but recorded.Usually not felt, but recorded.

MinorMinor 3.0-3.93.0-3.9 Often felt, but rarely causes Often felt, but rarely causes damage.damage.

LightLight 4.0-4.94.0-4.9 Noticeable shaking of indoor items, Noticeable shaking of indoor items, rattling noises. Significant damage rattling noises. Significant damage unlikely. unlikely.

ModerateModerate

5.0-5.95.0-5.9 Can cause major damage to poorly Can cause major damage to poorly constructed buildings over small constructed buildings over small regions. Slight damage to well-regions. Slight damage to well-designed buildings. designed buildings.

StrongStrong 6.0-6.96.0-6.9 Can be destructive in areas up to Can be destructive in areas up to about 100 miles across in populated about 100 miles across in populated areas. areas.

MajorMajor 7.0-7.97.0-7.9 Can cause serious damage over Can cause serious damage over larger areas.larger areas.

GreatGreat 8.0-8.98.0-8.9 Can cause serious damage in areas Can cause serious damage in areas several hundred miles across. several hundred miles across.

Rare GreatRare Great 9.0 or greater9.0 or greater Devastating in areas several Devastating in areas several thousand miles across. thousand miles across.

How Do Scientists Know How Do Scientists Know Where an Earthquake Has Where an Earthquake Has

Happened?Happened? The location below the Earth’s surface where the earthquake starts is The location below the Earth’s surface where the earthquake starts is

called the called the hypocenterhypocenter.. The location directly above the hypocenter on the Earth’s surface is called The location directly above the hypocenter on the Earth’s surface is called

the the epicenterepicenter..

It take three seismographs to locate an earthquake. Scientists draw a circle It take three seismographs to locate an earthquake. Scientists draw a circle on a map around the three seismographs where the radius of each is the on a map around the three seismographs where the radius of each is the distance from the station to the earthquake, the intersection of those three distance from the station to the earthquake, the intersection of those three circles is the epicenter. circles is the epicenter.

How Long Does an Earthquake How Long Does an Earthquake Last?Last?

Sometimes an earthquake Sometimes an earthquake has has foreshocksforeshocks. These are . These are smaller earthquakes that smaller earthquakes that happen in the same place as happen in the same place as the larger earthquake. the larger earthquake.

The largest, main The largest, main earthquake is called the earthquake is called the mainshockmainshock..

Mainshocks always have Mainshocks always have

aftershocksaftershocks that follow. that follow. These are smaller These are smaller earthquakes that occur earthquakes that occur afterwards in the same afterwards in the same place as the mainshock. place as the mainshock. Depending on the size of the Depending on the size of the mainshock, aftershocks can mainshock, aftershocks can continue for weeks, months, continue for weeks, months, or even years after the or even years after the mainshock! mainshock!

Famous Earthquakes Around the Famous Earthquakes Around the

WorldWorld San Francisco, California: April 18, 1906 San Francisco, California: April 18, 1906

(Magnitude: About 8)(Magnitude: About 8)

Tokyo, Japan: September 1, 1923 Tokyo, Japan: September 1, 1923

(Magnitude: about 8.25)(Magnitude: about 8.25)

Chile: May 22, 1960 Chile: May 22, 1960

(Magnitude: About 9)(Magnitude: About 9)

Anchorage, Alaska: March 27, 1964Anchorage, Alaska: March 27, 1964

(Magnitude: About 8.5)(Magnitude: About 8.5)

How Many Earthquakes How Many Earthquakes Happen Each Year?Happen Each Year?

1

10

100

1,000

10,000

100,000

1,000,000

1 2 3 4 5 6 7 8

Magnitude of Earthquakes

Num

ber

of

Ear

thqu

akes

Where do Earthquakes Occur Where do Earthquakes Occur Most Often in the United Most Often in the United

States?States?

11

7

3

11

1 1

Alaska

California

Missouri

Hawaii

Nevada

Montana

Idaho

Top 25 Earthquakes in the Top 25 Earthquakes in the United States United States (Percentage)(Percentage)

44%

28%

12%

4%

4%

4%4%

Alaska

California

Missouri

Hawaii

Nevada

Montana

Idaho

Earthquake DamageEarthquake Damage

What Have You Learned?What Have You Learned?

Click Here

To review the Brain Pop video and take

the quiz!

Click Here

To test your knowledge

about earthquake vocabulary!

ReferencesReferences http://earthquake.usgs.gov/learning/kids.phphttp://earthquake.usgs.gov/learning/kids.php http://www.exploratorium.com/faultline/http://www.exploratorium.com/faultline/ http://teacher.scholastic.com/activities/wwatch/earthttp://teacher.scholastic.com/activities/wwatch/eart

hquakes/hquakes/ http://www.fema.gov/kids/quake.htmhttp://www.fema.gov/kids/quake.htm http://www.ditto.com/default.aspxhttp://www.ditto.com/default.aspx Earthquake StatisticsEarthquake Statistics The Largest Earthquakes in the United StatesThe Largest Earthquakes in the United States http://www.brainpop.com http://www.brainpop.com ““Mountains, Volcanoes, and Earthquakes” Mountains, Volcanoes, and Earthquakes” Harcourt Harcourt

Earth Science Grade 5Earth Science Grade 5, p. C14., p. C14.