ESAY+2.1

toc

=Chapter 2.1=

Vocabulary

 * Earthquake**:shaking/trembling of rocks underneath Earth's surface
 * Stress**:the force that acts/pushes on a rock to change it
 * Shearing**:form of stress that pushes two large pieces of rock in opposite directions
 * Tension**:form of stress that pulls apart a rock so that the middle is thinner than that of the sides/edges
 * Compression**:form of stress that squeezes rock until it folds or breaks
 * Deformation**:change of volume or shape in Earth's crust
 * Fault**:a place where two rocks have slipped past each other
 * Strike-slip Fault**:a fault where two rocks have slipped past each other with very little to no up-down motion
 * Normal Fault:** a normal fault is at an angle, so that one side is on top, and the other is on the bottom
 * Reverse Fault**:similar structure to a normal fault except for that they move differently
 * Fault-block mountain:** A mountain that forms where a normal fault lifts a block of rock.
 * Fold:** A bend in rock that forms where part of the Earth's crust is compressed.
 * Anticline:** A fold in the rock that bends upward
 * Syncline:** A fold in the rock that bends downward
 * Plateau:** A large area of flat land elevated high above sea level.

**Stress in the Crust**

 * An earthquake is the shaking and trembling of rock beneath surface.
 * This movement of earth creates powerful forces that squeeze or pull the rock in the crust.
 * These forces are examples of stress, that forces the rock to change its shape or volume.
 * The three types of stress are shearing, tension, and compression.


 * Kinds of faults**
 * A fault usually occurs along the plate boundaries, where forces of plate motion compress, pull, or shear the crust so much that the crust breaks.
 * There are three types of faults. Strike slip faults occur when two two rocks on either side of the fault slip past each other.
 * A normal fault is when the fault is at an angle, where one block of rock lies below the fault.A reverse fault has the same structure of a normal fault, but the block moves in opposite direction.

Friction is the force that opposes the motion of one surface as it moves across another surface.
 * Friction along faults**
 * The San Andreas fault in California forms a transform boundary between the pacific plate and the North American plate.
 * In most places among the San Andreas fault, friction is high and the stress builds up until an earthquake releases the stress and the plates slide past each other.


 * Mountain Building**

The forces of plate movement can build up earths surface.
 * Over millions of years, fault movement can change a flat plain into a towering mountain range.
 * When a normal fault uplifts a block of rock, a **fault-block mountain** is formed. The Sierra Nevada of california is a fault-block mountain range.
 * Under certain conditions plate movement cause the crust to fold. The collision of two plates can cause compression and folding of the crust.
 * The Himalayas in Asia and the Alps in Europe were formed when pieces of the crust folded during the collision of two plates.


 * Anticlines and Synclines**

Geologists use the terms anticline and synclines to describe upward and downward folds in rock.
 * A fold in the rock that bends upward is called anticline.
 * A fold in the rock that bends downward is called syncline.


 * Plateau**

The force that raises mountains can also raise plateaus.
 * A plateau is a flat land elevated high above sea level.
 * A plateau consists of many layers of rock.
 * The kaibab plateau forms the north rim of the Grand Canyon in Arizona.



back to homepage