California Science, 4Th Grade, Ch. 5, Lesson 2 Earthquakes

Front 1

Earth's crust

Back 1

-Earth's outermost layer and Earth's thinnest layer

Front 2

Earth's plates

Back 2

-gigantic slabs of rock on Earth, always moving
-what Earth's crust is made from

Front 3

faults

Back 3

-breaks or cracks in Earth's crust where the plates come together
-cause earthquakes

Front 4

earthquakes

Back 4

-movements in Earth's crust that are caused by a sudden shift of Earth's plates

Front 5

Where do earthquakes occur?

Back 5

-most happen near the edges of Earth's plates

Front 6

What causes an earthquake?

Back 6

-most happen when Earth's plates meet (the plates are always moving)
-Energy released by sudden motion of plates shakes the crust

Front 7

creep

Back 7

-slow movement along faults
-usually do no cause large earthquakes where faults are "creeping"

Front 8

Types of Faults

Back 8

-Normal Fault
-Reverse Fault
-Strike-slip Fault

Front 9

Normal Fault

Back 9

-plates PULL apart
-rocks above the fault surface MOVE DOWN
-example is the Sierra Nevada mountains which are formed this way

Front 10

Reverse Fault

Back 10

-plates PUSH together
-rocks above the fault MOVE UPWARD
-example is the Himalayas which are formed this way

Front 11

Strike-Slip Fault

Back 11

-rocks slide PAST each other in different directions
-example is the San Andreas Fault

Front 12

Where are the vibrations of an earthquake strongest?

Back 12

-where the earthquake first begins - below the ground
-the vibrations move through Earth's crust in all directions

Front 13

tsunami

Back 13

-a giant ocean wave
-usually caused by earthquakes on the ocean floor
-some are caused by earthquakes on the ocean floor
-a few are caused by underwater landslides and volcanoes

Front 14

Effects of Tsunamis

Back 14

-can wash away shores and damage property
-can harm people and animals