Chapter 2 - 1 – Stress in the crust (part 1)
1. Stress in the crust-
A. A force that changes earth's surface
2. Types of Stress –
A. Three types (fig. 2, page 45)
1. Shearing B
a. slide past each other
2. Tension C
a. pull apart from each other
3. Compression D
a. press together
1. Earth's crust can bend,
stretch, break, tilt, fold, and slide
A. Slow shift of plates's
is the cause
figures to label & explain
Chapter 2 - 1 Faults (Part II )
hanging wall -
1. Faults –
A.Where do they occur?
motion compresses, pulls or shears the crust
it to break.
2. Kinds of Faults –
A. Strike-slip faults (fig. 3, pg. 46)
1. caused by shearing
B. Normal faults (fig. 4, pg. 46)
C. Reverse faults (fig. 5, pg. 47)
2. convergent boundary
3. blocks move opposite of normal
A. caused when two objects rub against each other
B..How does fiction play a role in earthquakes?
4. Does the San Andreas fault affect us in Southern
5. What will happen millions of years from now to Southern
6. Mountain Building –
A. Mountains formed by faulting – (fig.
7, pg. 48)
B. Mountains formed by folding – (fig.
8, pg. 49)
Chapter 2 - 2 Measuring Earthquakes
1. How many earthquakes are there everyday worldwide?
2. What two questions are always asked when an earthquake happens?
A. How big was it?
B. Where was the epicenter?
3. Most earthquakes begin in the lithosphere.
A. within 100 Km of the surface
4. Seismic waves
A. 3 catergories
1. P waves
2. S waves
waves (L waves)
severe ground movement
wksht. to label
Chapter 2 - 2 Measuring Earthquakes (part II)
Ch. 2-2 (part II) Measuring Earthquakes
1. Detecting Seismic waves
1. Measures and records vibrations
B. Fig. 13, pg. 56
2. 3 ways to measure earthquakes
A. Mercalli scale
1. Used in early 20th century
2. Not a precise measurement
3. Fib. 14, pg 57
B. Richter scale
1. Rating of the size of seismic
2. Used for about 50 years then
C. Moment Magnitude scale
1. Used today
2. But news reports give the
number attached to the Richter
3. Locating the epicenter
A. Need 3 readings from 3 different seismographs
Fig. 17, pg. 59