“It’s an earthquake”

I) Forces in Earth's Crust

Earthquake Effects - Ground Shaking Northridge, CA 1994

Earthquake Effects - Ground Shaking Northridge earthquake 1994 Parking garage at Cal State Northridge Northridge, CA 1994

Earthquake Effects - Ground Shaking Loma Prieta, CA 1989 KGO-TV News ABC-7

A) Stress in the Crust a) earthquake- the shaking and trembling that results from the movement of rock beneath Earth’s surface b) stress- force that acts on rock to change its shape or volume

Three Types of Stresses B) Types of Stress Three Types of Stresses

Shearing, Tension, and Compression

1) Shearing a) stress that pushes a mass of rock in two opposite directions b) It can cause rock to break and slip apart or to change its shape c) associated with a transform boundary

2) Tension a) stress that pulls on the crust b) It can cause rock to stretch so that it becomes thinner in the middle c) associated with a divergent boundary

3) Compression a) stress that squeezes rock b) It can cause rock to fold or break c) associated with a convergent boundary

4) Deformation - any change in the volume or shape of Earth’s crust - it causes it to bend, stretch, break, tilt, fold, and slide - changes occur so slowly that they cannot be observed directly

Kinds of Faults video clip

C) Kinds of Faults 1) a fault is a break in Earth’s crust where slabs of crust slip past each other.

Three Types of Faults (1)Strike-Slip (3)Reverse (thrust) (2)Normal Form depending on type of plate motion and complex reaction of earth’s lithospheric blocks Strike-slip Normal Thrust (2)Normal

1) Strike-slip fault a) created by shearing b) rocks slip past each other sideways with little up-or-down motion c) located along a transform boundary

A strike-slip fault that is clearly visible at the surface is the San Andreas Fault in California

Strike-slip Fault Example Landers, CA 1992

Strike-slip Fault Example

2) Normal Fault a) caused by tension in the Earth’s crust b) the hanging wall slips downward below the footwall c) located along divergent plate boundaries

A normal falut created the Sandia Mountains in New Mexico

Normal Fault Example Dixie Valley-Fairview Peaks, Nevada earthquake December 16, 1954

3) Reverse Fault a) caused by compression in the Earth’s crust b) the hanging wall slides up and over the footwall c) located along convergent plate boundaries

A reverse fault formed Mt A reverse fault formed Mt. Gould in Glacier National Park, beginning 60 million years ago.

D) Hanging wall & Footwall hanging wall footwall

D) Hanging wall & Footwall

1) Hanging wall a) The half of the fault that lies above You can “hang” from a hanging wall

2) Footwall a) The half of the fault that lies below It is “Normal” to be able to walk up the slope

It is “Normal” to be able to walk up a slope and “Reverse” of “Normal” to walk upside down

E) Friction 1) the force that opposes the motion of one surface as it moves across another surface

Bill Nye Friction

F) Mountain Building

1) Mountains Formed by Faulting a) Fault-block mountain - when two normal faults uplift a block of rock Two normal faults can form fault-block mountains, such as the Teton Range near the border of Wyoming and Idaho

2) Mountains Formed by Folding a) folds are bends in rock that form when compression shortens and thickens part of Earth’s crust Some of the world’s largest mountain ranges, including the Himalayas in Asia and the Alps in Europe are formed in when pieces of the crust are folded

3) Anticlines and Synclines

a) Anticline- a fold in rock that bends upward into an arch The folded rock layers of an anticline can be seen on this cliff on the coast of England

b) Syncline- a fold in rock that bends downward in the middle to form a bowl

4) Plateaus a) a large area of flat land elevated high above sea level The Kaibob Plateau, which forms the North Rim of the Grand Canyon in Arizona. The Kaibob Plateau is part of the Colorado Plateau.

“It’s an earthquake”

Review

How does deformation change Earth’s surface? It causes it to bend, stretch, break, tilt, fold, and slide.

(1)Strike-Slip (3)Reverse (thrust) (2)Normal What are the three types of faults? 1) Strike-slip fault, 2) Normal fault, 3) Reverse fault (1)Strike-Slip (3)Reverse (thrust) (2)Normal

What type of force causes a strike-slip fault? shearing =

What type of force causes a normal fault? tension =

What type of force causes a reverse (thrust) fault? compression =

What are the main types of stress in rock? shearing, tension, and compression

What is an earthquake the shaking and trembling that results from the movement of rock beneath Earth’s surface

What kind of fault occurs when the hanging wall slides up and over the footwall? reverse fault

What type of fault has little up or down movement? strike-slip fault

What type of fault occurs when the hanging wall slips downward below the footwall? normal fault

What half (above or below) of the fault does the hanging wall lie? footwall

What half (above or below) of the fault does the footwall lie? hanging wall footwall

How is a fault-block mountain formed? created when two normal faults uplift a block of rock

What is the force that opposes the motion of one surface as it moves across another friction

What type of force created the Himalayas and Alps? folding

What is a fold in the rock that bends upward? anticline

What is a large area of flat land high above sea level? plateau

What is a fold in rock that bends downward? syncline

Elsinore fault

The Elsinore fault zone is one of the largest in southern California, and in historical times, has been one of the quietest. The southeastern extension of the Elsinore fault zone, the Laguna Salada fault, ruptured in 1892 in a magnitude 7 quake, but the main trace of the Elsinore fault zone has only seen one historical event greater than magnitude 5.2 -- the earthquake of 1910, a magnitude 6 shock near Temescal Valley, which produced no known surface rupture and did little damage. At its northern end, the Elsinore fault zone splays into two segments, the Chino fault and the Whittier fault. At its southern end, the Elsinore fault is cut by the Yuha Wells fault from what amounts to its southern continuation: the Laguna Salada fault. Several of the fault strands which make up the Elsinore fault zone possess their own names. Northwest of Lake Elsinore are the Glen Ivy North and Glen Ivy South faults. Heading southeast from Lake Elsinore, the two parallel fault strands are the Wildomar fault (the more easterly) and the Willard fault.