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

Table of Contents Georgia Performance Standards Georgia Performance Standards Georgia Performance Standards Georgia Performance Standards What is an Earthquake? What is an Earthquake? What is an Earthquake? What is an Earthquake? What are Earth’s layers? What are Earth’s layers? What are Earth’s layers? What are Earth’s layers? What are Plate Tectonics? What are Plate Tectonics? What are Plate Tectonics? What are Plate Tectonics? What Happens When Plates Move? What Happens When Plates Move? What Happens When Plates Move? What Happens When Plates Move? Types of Plate Boundaries Types of Plate Boundaries Types of Plate Boundaries Types of Plate Boundaries The Theory of Continental Drift The Theory of Continental Drift The Theory of Continental Drift The Theory of Continental Drift What is a Fault? What is a Fault?What is a Fault?What is a Fault? What Happens when an Earthquake Starts? What Happens when an Earthquake Starts? What Happens when an Earthquake Starts? What Happens when an Earthquake Starts? How are Earthquakes Measured? How are Earthquakes Measured? How are Earthquakes Measured? How are Earthquakes Measured? The Richter Magnitude Scale The Richter Magnitude Scale The Richter Magnitude Scale The Richter Magnitude Scale How Long Does an Earthquake Last? How Long Does an Earthquake Last? How Long Does an Earthquake Last? How Long Does an Earthquake Last? How Many Earthquakes Happen Each Year? How Many Earthquakes Happen Each Year? How Many Earthquakes Happen Each Year? How Many Earthquakes Happen Each Year? Where Do Earthquakes Occur Most Often in the United States? Where Do Earthquakes Occur Most Often in the United States? Where Do Earthquakes Occur Most Often in the United States? Where Do Earthquakes Occur Most Often in the United States? The 25 Largest Earthquakes in the United States The 25 Largest Earthquakes in the United 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 Famous Earthquakes Around the World Famous Earthquakes Around the World Photos of Earthquake Damage Photos of Earthquake Damage Photos of Earthquake Damage Photos of Earthquake Damage What Have You Learned? What Have You Learned? What Have You Learned? What Have You Learned? References References References

Georgia Performance Standards S5Cs4: Students will use ideas of system, model, change, and scale in exploring scientific and technological matters. S5Cs4: Students will use ideas of system, model, change, and scale in exploring scientific and technological matters. S5E1: Students will identify surface features of the Earth caused by constructive and destructive processes. S5E1: Students will identify surface features of the Earth caused by constructive and destructive processes. S5P1: Students will verify that an object is the sum of its parts. S5P1: Students will verify that an object is the sum of its parts. M5D1: Students will analyze graphs. M5D1: Students will analyze graphs. M5N5: Students will understand the meaning of percentage M5N5: Students will understand the meaning of percentage

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

What are Earth’s Layers? The Earth’s crust is the outer layer and is made of rock. It is very thin compared to the other layers. The Earth’s crust is the outer layer and is made of rock. It is very thin compared to the other layers. The mantle is the very hot layer of rock beneath the crust. No one has ever been to the mantle, but rock from the mantle sometimes reaches the Earth’s surface through volcanoes. The mantle is the very hot layer of rock beneath the crust. No one has ever been to the mantle, but rock from the mantle sometimes reaches the Earth’s surface through volcanoes. The outer core is made of liquid, or molten iron. The outer core is made of liquid, or molten iron. The inner core is made of solid iron. Even though the core is the hottest layer, great pressure at the center of the Earth keeps the inner core solid. The inner core is made of solid iron. Even though the core is the hottest layer, great pressure at the center of the Earth keeps the inner core solid. Inner CoreOuter core MantleCrust

What are Plate Tectonics? Earth’s surface is made up of many plates that float on the soft rock of the mantle. As the mantle moves, the plates also move. Earth’s surface is made up of many plates that float on the soft rock of the mantle. As the mantle moves, the plates also move. Plates move only a few centimeters each year. Plates move only a few centimeters each year. When one plate moves, it affects the other plates. When one plate moves, it affects the other plates. As plates move around, they cause great changes in the Earth’s surface, such as mountains, valleys, volcanoes, and earthquakes! As plates move around, they cause great changes in the Earth’s surface, such as mountains, valleys, volcanoes, and earthquakes!

What Happens When Plates Move? Plate Tectonics Convergent Plate Boundaries plates crunch together and release energy mountains develop, volcanoes erupt, and earthquakes can happen Divergent Plate Boundaries plates pull apart and new crust is formed valleys and volcanoes develop, earthquakes can occur Transform Boundaries plates slide past each other Lots of earthquakes!

Types of Boundaries Wegener’s Theory of Continental Drift

What is a Fault? Many earthquakes occur along faults in the Earth’s crust. A fault is a place where pieces of the plates move. Many earthquakes occur along faults in the Earth’s crust. A fault is a place where pieces of the plates move. A normal fault is where tension weakens the crust until the rock fractures, and one rock moves downward from another. This occurs when two plates are pulling apart, as in a divergent boundary. A normal fault is where tension weakens the crust until the rock fractures, and one rock moves downward from another. This occurs when two plates are pulling apart, as in a divergent boundary. A strike-slip fault is where two blocks of rock are moving past each other horizontally, as in a transform boundary. The famous San Andreas Fault is a strike-slip fault. A strike-slip fault is where two blocks of rock are moving past each other horizontally, as in a transform boundary. The famous San Andreas Fault is a strike-slip fault.San Andreas Fault San Andreas Fault A Reverse fault is where a fault block is forced upward, usually during a collision with another block, as in a convergent boundary. A Reverse fault is where a fault block is forced upward, usually during a collision with another block, as in a convergent boundary.

What Happens When an Earthquake Starts? The sudden release of energy from an earthquake sends out several different shaking movements, or seismic waves. The sudden release of energy from an earthquake sends out several different shaking movements, or seismic waves. Surface waves are ripples of energy that spread outward when rocks slip past each other along a fault, just like throwing a stone into a calm pond. Surface waves are ripples of energy that spread outward when rocks slip past each other along a fault, just like throwing a stone into a calm pond. Body waves are seismic waves that travel through material rather than over its surface. There are two types of body waves: P-waves and S-waves. Body waves are seismic waves that travel through material rather than over its surface. There are two types of body waves: P-waves and S-waves. The P-wave is also known as the sound wave. It travels through the interior of the Earth rather than over the surface as a series of squeezes and stretches. P-waves reach everywhere around the Earth after about 20 minutes. The P-wave is also known as the sound wave. It travels through the interior of the Earth rather than over the surface as a series of squeezes and stretches. P-waves reach everywhere around the Earth after about 20 minutes. The S-wave, or shear wave, produces a shaking motion, like if you tied a rope to a poll and shook the other end side to side. S-waves can only travel in solid material. The S-wave, or shear wave, produces a shaking motion, like if you tied a rope to a poll and shook the other end side to side. S-waves can only travel in solid material.

How are Earthquakes Measured? Earthquakes are measured by instruments called seismographs. It has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the heavy weight does not. The spring that it is hanging from absorbs all the movement. The seismograph records the difference in position between the shaking part and the motionless part. Earthquakes are measured by instruments called seismographs. It has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the heavy weight does not. The spring that it is hanging from absorbs all the movement. The seismograph records the difference in position between the shaking part and the motionless part. The recording is called a seismogram. It is used to determine how large the earthquake was. A short wiggly line that wiggles very little means a small earthquake. A long wiggly line that wiggles a lot means a large earthquake. The recording is called a seismogram. It is used to determine how large the earthquake was. A short wiggly line that wiggles very little means a small earthquake. A long wiggly line that wiggles a lot means a large earthquake.

The Richter Magnitude Scale Description Richter Magnitudes Earthquake Effects Micro Less than 2.0 Microearthquakes, not felt. Very Minor Usually not felt, but recorded. Minor Often felt, but rarely causes damage. Light Noticeable shaking of indoor items, rattling noises. Significant damage unlikely. Moderate Can cause major damage to poorly constructed buildings over small regions. Slight damage to well-designed buildings. Strong Can be destructive in areas up to about 100 miles across in populated areas. Major Can cause serious damage over larger areas. Great Can cause serious damage in areas several hundred miles across. Rare Great 9.0 or greater Devastating in areas several thousand miles across.

How Do Scientists Know Where an Earthquake Has Happened? The location below the Earth’s surface where the earthquake starts is called the hypocenter. The location below the Earth’s surface where the earthquake starts is called the hypocenter. The location directly above the hypocenter on the Earth’s surface is called the epicenter. The location directly above the hypocenter on the Earth’s surface is called the epicenter. 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 distance from the station to the earthquake, the intersection of those three circles is the epicenter. 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 distance from the station to the earthquake, the intersection of those three circles is the epicenter.

How Long Does an Earthquake Last? Sometimes an earthquake has foreshocks. These are smaller earthquakes that happen in the same place as the larger earthquake. Sometimes an earthquake has foreshocks. These are smaller earthquakes that happen in the same place as the larger earthquake. The largest, main earthquake is called the mainshock. The largest, main earthquake is called the mainshock. Mainshocks always have aftershocks that follow. These are smaller earthquakes that occur afterwards in the same place as the mainshock. Depending on the size of the mainshock, aftershocks can continue for weeks, months, or even years after the mainshock! Mainshocks always have aftershocks that follow. These are smaller earthquakes that occur afterwards in the same place as the mainshock. Depending on the size of the mainshock, aftershocks can continue for weeks, months, or even years after the mainshock!

Famous Earthquakes Around the World San Francisco, California: April 18, 1906 San Francisco, California: April 18, 1906 (Magnitude: About 8) Tokyo, Japan: September 1, 1923 Tokyo, Japan: September 1, 1923 (Magnitude: about 8.25) Chile: May 22, 1960 Chile: May 22, 1960 (Magnitude: About 9) Anchorage, Alaska: March 27, 1964 Anchorage, Alaska: March 27, 1964 (Magnitude: About 8.5)

How Many Earthquakes Happen Each Year?

Where do Earthquakes Occur Most Often in the United States?

Top 25 Earthquakes in the United States (Percentage)

Earthquake Damage

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!

References es/ es/ es/ es/ Earthquake Statistics Earthquake Statistics Earthquake Statistics Earthquake Statistics The Largest Earthquakes in the United States The Largest Earthquakes in the United States The Largest Earthquakes in the United States The Largest Earthquakes in the United States “Mountains, Volcanoes, and Earthquakes” Harcourt Earth Science Grade 5, p. C14. “Mountains, Volcanoes, and Earthquakes” Harcourt Earth Science Grade 5, p. C14.