Chapter Menu Lesson 1: Earthquakes and Plate Boundaries Lesson 2: Earthquakes and Seismic Waves Lesson 3: Measuring Earthquakes Lesson 4: Earthquake Hazards and Safety Click on a hyperlink to view the corresponding lesson.

6.1 Earthquakes and Plate Boundaries elastic strain focus

Earthquake The rupture and sudden movement of rocks along a fault. 6.1 Earthquakes and Plate Boundaries Earthquake The rupture and sudden movement of rocks along a fault. A fault is a fracture surface along which rocks can slip. Majority of earthquakes occur in Earth’s crust. Part of the energy released from earthquakes spreads as complex waves.

6.1 Earthquakes and Plate Boundaries Earthquake (cont.)

6.1 Earthquakes and Plate Boundaries Elastic Strain Energy Elastic strain is the energy stored as a material changes in shape. When rocks can no longer change shape—the fault breaks and slips, causing earthquakes.

Elastic Strain Energy (cont.) 6.1 Earthquakes and Plate Boundaries Elastic Strain Energy (cont.)

6.1 Earthquakes and Plate Boundaries Focus The focus is the location on the fault where an earthquake begins. The closer the focus is to the surface, the stronger the shaking will be.

6.1 Earthquakes and Plate Boundaries Fault Zones Plate boundaries are usually made of multiple faults called zones that are 40–200 km wide.

Plate Boundaries and Earthquakes 6.1 Earthquakes and Plate Boundaries Plate Boundaries and Earthquakes Lithospheric plates interact at different plate boundaries and produce earthquakes. Earthquake size and depth and fault type depend on the type of plate boundary.

Plate Boundaries and Earthquakes (cont.) 6.1 Earthquakes and Plate Boundaries Plate Boundaries and Earthquakes (cont.)

Divergent Plate Boundaries 6.1 Earthquakes and Plate Boundaries Divergent Plate Boundaries Rocks break under tension stress, forming normal faults Most earthquakes at divergent plate boundaries occur at relatively shallow depths in the crust and are relatively small in size.

Convergent Plate Boundaries 6.1 Earthquakes and Plate Boundaries Convergent Plate Boundaries Rocks break under compression stress, forming reverse faults. Deepest earthquakes happen at subduction zones Result in most devastating earthquakes in Earth’s history.

Transform Plate Boundaries 6.1 Earthquakes and Plate Boundaries Transform Plate Boundaries Plates slide horizontally past one another, forming strike-slip faults. Earthquakes mainly occur at relatively shallow depths. When boundaries run through continents, they can cause major earthquakes.

Earthquakes Away from Plate Boundaries 6.1 Earthquakes and Plate Boundaries Earthquakes Away from Plate Boundaries

Earthquakes Away from Plate Boundaries (cont.) 6.1 Earthquakes and Plate Boundaries Earthquakes Away from Plate Boundaries (cont.) New Madris Earthquakes of 1911 Millions of years ago, a long zone of intense faulting was formed when the crust began to pull apart, but did not break completely. Today, the crust is being compressed, or squeezed together.

Strike-slip faults occur at what type of plate boundary? 6.1 Earthquakes and Plate Boundaries A B C D Strike-slip faults occur at what type of plate boundary? A convergent plate boundary B transform plate boundary C divergent plate boundary D subduction plate boundary Lesson 1 Review

The focus of an earthquake is ____. 6.1 Earthquakes and Plate Boundaries A B C D The focus of an earthquake is ____. A where an earthquake is first felt on the surface of Earth B where an earthquake dissipates C where the fault and a plate meet D where an earthquake begins Lesson 1 Review

A divergent plate boundary B convergent plate boundary 6.1 Earthquakes and Plate Boundaries A B C D Which boundary is associated with earthquakes that occur at relatively shallow depths and are small in size? A divergent plate boundary B convergent plate boundary C transform plate boundary D subduction plate boundary Lesson 1 Review

End of Lesson 1

6.2 Earthquakes and Seismic Waves epicenter primary wave secondary wave

6.2 Earthquakes and Seismic Waves Waves of energy that are produced at the focus of an earthquake. Waves move outward from the focus in all directions.

6.2 Earthquakes and Seismic Waves Epicenter The point on Earth’s surface directly above the earthquake’s focus. How do seismograph stations help determine an earthquake’s epicenter?

Primary Waves (P-waves) 6.2 Earthquakes and Seismic Waves Primary Waves (P-waves)

Secondary Waves (S-waves) 6.2 Earthquakes and Seismic Waves Secondary Waves (S-waves)

6.2 Earthquakes and Seismic Waves Surface Waves

Surface Waves (cont.)

Using Seismic Wave Data 6.2 Earthquakes and Seismic Waves Using Seismic Wave Data Used to determine the composition of Earth’s interior If close to the focus, the S-wave is not very far behind the P-wave. If far from the focus, the S-wave travels far behind the P-wave. P-waves arrive first, then S-waves, and surface waves last

Mapping Earth’s Internal Structure 6.2 Earthquakes and Seismic Waves Mapping Earth’s Internal Structure Earth’s internal structure can be determined by analyzing the paths of seismic waves. Speed and direction of waves change when properties of the material traveled through changes.

Mapping Earth’s Internal Structure (cont.) 6.2 Earthquakes and Seismic Waves Mapping Earth’s Internal Structure (cont.) Shadow zones are areas that do not receive seismic waves. Secondary waves only travel through solids and cannot penetrate the outer core. Primary waves can travel through solids and their paths bend through liquids. Because primary waves bend, scientists believe that the outer core is composed of liquid.

Mapping Earth’s Internal Structure (cont.)

Surface waves cause rock particles to move with a(n) _____. 6.2 Earthquakes and Seismic Waves A B C D Surface waves cause rock particles to move with a(n) _____. A side-to-side motion B rolling motion C up-and-down and side-to-side motion D side-to-side and rolling motion Lesson 2 Review

What is a characteristic of P-waves? 6.2 Earthquakes and Seismic Waves A B C D What is a characteristic of P-waves? A They cause rock particles to vibrate perpendicular to the direction that waves travel. B They cause rock particles to vibrate in the same direction that waves travel. C They only travel through solids. D They are the slowest seismic wave. Lesson 2 Review

Which type of wave causes the most destruction at Earth’s surface? 6.2 Earthquakes and Seismic Waves A B C D Which type of wave causes the most destruction at Earth’s surface? A P-wave B S-wave C surface wave D combination of P-wave and surface wave Lesson 2 Review

End of Lesson 2

6.3 Measuring Earthquakes seismograph seismogram

Measuring Earthquakes Scientists determine size of earthquakes by measuring how much the rock slips along the fault. They also analyze the heights of the seismic waves, which indicate how much energy is released by an earthquake.

Seismograph Records size, direction, and the movement time of ground 6.3 Measuring Earthquakes Seismograph Records size, direction, and the movement time of ground Records the arrival times of the P- and S-waves

Seismogram Record of the seismic waves 6.3 Measuring Earthquakes Seismogram Record of the seismic waves Used to calculate the size and locations of earthquakes

6.3 Measuring Earthquakes Reading a Seismogram Wave heights indicate the amount of ground motion for each type of wave. Difference between the arrival times of P-waves and S-waves determines the distance of the seismograph from the epicenter.

Locating an Epicenter Triangulation is used to locate the epicenter. 6.3 Measuring Earthquakes Locating an Epicenter Triangulation is used to locate the epicenter. This method is based on the speeds of the seismic waves. At least three seismographs must record the distances.

1. Find the arrival time differences. 6.3 Measuring Earthquakes 1. Find the arrival time differences.

2. Find the difference from the epicenter. 6.3 Measuring Earthquakes 2. Find the difference from the epicenter.

3. Plot the distance on a map. 6.3 Measuring Earthquakes 3. Plot the distance on a map.

Measuring Earthquake Size Magnitude measures the amount of energy released by an earthquake. Determined by the buildup of elastic strain energy in the crust, at place where rupture occurs Magnitude scale is based on record of height of ground motion and ranges from 0–9. Richter Magnitude Scale

Moment Magnitude Scale 6.3 Measuring Earthquakes Moment Magnitude Scale Used today because it is a more accurate scale for measuring earthquake size. Based on the amount of energy released during an earthquake.

6.3 Measuring Earthquakes Earthquake Intensity Intensity values vary and depend on the distance from the epicenter and the local geology. Usually, the maximum intensity is found near the epicenter.

What information should be known in order to determine the epicenter? 6.3 Measuring Earthquakes A B C D What information should be known in order to determine the epicenter? A arrival time of P-waves and surface waves at two seismograph stations B arrival time of P- and S-waves at two seismograph stations C arrival time of P- and S-waves at three seismograph stations D arrival time of P-waves and surface waves at three seismograph stations Lesson 3 Review

Triangulation is used to determine an earthquake’s ____. A P-waves 6.3 Measuring Earthquakes A B C D Triangulation is used to determine an earthquake’s ____. A P-waves B S-waves C epicenter D magnitude Lesson 3 Review

What two factors influence intensity values? 6.3 Measuring Earthquakes A B C D What two factors influence intensity values? A population and distance from the epicenter B distance from the epicenter and distance from the ocean C population and local geology D local geology and distance from the epicenter Lesson 3 Review

End of Lesson 3

6.4 Earthquake Hazards and Safety liquefaction tsunami

6.4 Earthquake Hazards and Safety Most injuries result from the collapse of buildings and other structures. Other hazards that might result from an earthquake include fires, landslides, loose sediment, and tsunamis.

6.4 Earthquake Hazards and Safety Liquefaction The process by which shaking makes loose sediment move like a liquid.

Tsunami Powerful ocean waves caused by sudden movement of seafloor. 6.4 Earthquake Hazards and Safety Tsunami Powerful ocean waves caused by sudden movement of seafloor. Water along shoreline might move back rapidly toward the sea before the wave crashes on shore.

Avoiding Earthquake Hazards 6.4 Earthquake Hazards and Safety Avoiding Earthquake Hazards

6.4 Earthquake Hazards and Safety B C D What occurs when ground shaking causes loose sediment to act like a liquid? A convection B deposition C subduction D liquefaction Lesson 4 Review

B sudden movement of the seafloor C sudden movement of the continents 6.4 Earthquake Hazards and Safety A B C D What causes a tsunami? A liquefaction B sudden movement of the seafloor C sudden movement of the continents D magnitude Lesson 4 Review

What is a warning sign of a tsunami? A beach erosion B flash flooding 6.4 Earthquake Hazards and Safety A B C D What is a warning sign of a tsunami? A beach erosion B flash flooding C water moving back rapidly toward the sea D ships washing up on shore Lesson 4 Review

End of Lesson 4

Chapter Resources Menu Chapter Assessment California Standards Practice Concepts in Motion Image Bank Science Online Interactive Table Virtual Lab Click on a hyperlink to view the corresponding feature.

A compression, very deep earthquakes B C D What characteristics of an earthquake are associated with a convergent plate boundary? A compression, very deep earthquakes B strike-slip, very shallow earthquakes C tension, very shallow earthquakes D tension, very deep earthquakes Chapter Assessment 1

A only travel through liquids B C D S-waves ____. A only travel through liquids B are the first waves to reach the seismograph C only travel through solids D generally cause the most damage at Earth’s surface Chapter Assessment 2

A measure of the distance between the focus and the epicenter What is magnitude? A measure of the distance between the focus and the epicenter B measure of the distance between the P- and S-waves C measure of triangulation D measure of the amount of energy released by an earthquake Chapter Assessment 3

Most injuries from an earthquake result from ____. B C D Most injuries from an earthquake result from ____. A the shaking of Earth B the collapse of structures C sink holes D flash floods Chapter Assessment 4

A area that does not receive seismic waves B C D What is a shadow zone? A area that does not receive seismic waves B area directly above the focus C area directly above the epicenter D a fault Chapter Assessment 5

Where is the maximum intensity of an earthquake felt? A focus SCI 1.g A B C D Where is the maximum intensity of an earthquake felt? A focus B epicenter C fault D inland CA Standards Practice 1

What is the term for the energy stored as a material changes in shape? SCI 1.e A B C D What is the term for the energy stored as a material changes in shape? A elastic strain B kinetic energy C plastic strain D potential energy CA Standards Practice 2

If you are far from the focus of an earthquake, ____. SCI 7.g A B C D If you are far from the focus of an earthquake, ____. A the S-wave travels far behind the P-wave B the P-wave travels far behind the S-wave C the S- and P-wave have the same arrival time D the S-wave and surface wave have the same arrival time CA Standards Practice 3

What method is used to determine the epicenter of an earthquake? SCI 1.g A B C D What method is used to determine the epicenter of an earthquake? A triangulation B visual observation C identifying where the most damage is located D by measuring the size of the earthquake CA Standards Practice 4

Which area would be the best for an apartment complex? SCI 1.g A B C D Which area would be the best for an apartment complex? A area with solid bedrock B a bed of loose sediment C an area built of landfill D where the soil is sandy CA Standards Practice 5

Concepts in Motion 1

Concepts in Motion 2

Concepts in Motion 3

Image Bank

Interactive Table

End of Resources