# Inside Earth Chapter 2.1 Pages 54-61

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Inside Earth Chapter 2.1 Pages 54-61
Earth’s Crust in Motion Inside Earth Chapter 2.1 Pages 54-61

Stress(ed)? Stress is the measure of the amount of force applied to a given area.

Effect on Rocks Stress is the force that acts on a rock to change its shape or volume Adds energy to the rock.

Deformation Deformation: Any change in the shape or volume of Earth’s crust (caused by stress) Crust deforms from the force of plates colliding Transform boundaries.

Where is the Deformation?

Relieving Stress Over time, stress builds up in the plates
Eventually, the stress is released…

Earthquake!

Earthquakes The shaking and trembling that results from the movement of rock beneath Earth’s surface. Releases MASSIVE amounts of energy Generates seismic waves

Compression Definition: Squeezing Effect on Rock:
Makes rock layers thicker and shorter Associated Fault Type:  Reverse Fault Associated Plate Boundary: Convergent Boundary

Tension Definition: Pulling apart Effect on Rock:
Stretches making rocks longer and thinner Associated Fault Type:  Normal Fault Associated Plate Boundary: Divergent Boundary

Shear Definition: Moving in opposite directions Effect on Rock:
Think of shears or scissors Effect on Rock: Stress distorts the shapes of rocks. Associated Fault Type:  Strike-Slip Associated Plate Boundary: Transform

Faults A fault is a break in the lithosphere
Usually occur along plate boundaries, where the motions of plates compress, pull or shear the crust so much that the crust breaks. 3 Types of Faults Strike Slip Fault Normal Fault Reverse Fault

Hanging Wall Above the fault plane. Hanging (head) Wall Foot Wall

Foot Wall Below the fault plane Hanging (head) Wall Foot Wall

Which Wall’s Which? Hanging Wall Lantern Foot Wall Path

What about the surfaces causes friction?
Friction along Faults How rocks move determines how much friction there is between opposite sides of the fault Friction: a force that opposes the motion of one surface as it moves across another What about the surfaces causes friction? It exist because surfaces are not perfectly smooth.

Normal Fault Force: Tension (diverging)
Hanging wall: Moves down (with gravity)

Reverse Fault Force: Compression (converging)
Hanging wall: Moves up (against gravity)

Strike-Slip Fault Force: Shear (transform)
Rocks on both sides of the fault slide past each other

Landforms Topography: determined by its elevation, relief and landform
All landforms have elevation and relief A landform region is an area where the topography is similar.

Elevation The height above sea-level on Earth’s surface.

Relief The difference between the highest point of elevation and the lowest parts of an area have high relief low relief. Mountains Plains

Plateaus Have high elevation and relief
Perfectly smooth on top May be really thick (1,500m), streams or rivers can cut through.

Plains Flat or gently rolling land with low relief and varying elevation. Depends on location… Coastal Plains have low elevation at or near sea level along the coast. Interior Plains are away from the coast, causing varied elevation.

Mountains A landform with high elevation and relief
Mountain Ranges are groups of mountains that are closely related in shape, structure and age.

Moraine Lake, CO Rockies

Himalayan Mountains, India

Mountains formed From Faulting
Normal Faults uplift blocks of rock and the hanging wall drops.

Mountains formed From Folding
When continental plates collide, stress can cause rock layers to fold. Creates bends in the rock layers Himalayas Mts. Appalachian Mountains

Anticline A term used to describe folds in rocks
An arching fold in the rock layers or “apex”

of the Archways World

Syncline A downward pointing fold or “slump”

Anticline/Syncline

Anticline/Syncline

What to Work On Read Section 2.1 (pages 54-61)
Answer section review questions (page 61, #1-4)