Chapter 19 Study Guide

Question 1

Which wave arrives at a seismic facility first?

Answer 1

Primary wave (p-wave)

Question 2

Where does an earthquake originate?

Answer 2

It originated at what is called the focus (under the ground)

Question 3

What stress type pulls a material apart and which boundary is it associated?

Answer 3

Tension and a divergent boundary

Question 4

What stress push minerals toward each other and which boundary is it associated with?

Answer 4

Compression, and convergent boundaries

Question 5

What type of stress does the material slide past each other and which boundary is associated with it?

Answer 5

Shear and transform boundary

Question 6

Where is the epicenter located in reference to the focus?

Answer 6

It is located directly above the focus (on the surface)

Question 7

Explain (in detail) what the difference is between elastic/plastic deformation (not definition!)

Answer 7

Any stress on a material means elastic deformation (rock changed, but not permanent). After stress is greater than elastic limit, plastic deformation (changes permanent).

Question 8

What does a normal fault look like? What is associated with stress, movement, and boundary of the fault?

Answer 8

Right hanging side sliding down, left rising up (moving apart)
Stress: Tension
Movement: Vertical (down)
Boundary: divergent

Question 9

What does a reverse fault look like? What is associated with stress, movement, and boundary of the fault?

Answer 9

Hanging up, bottom down, coming together.
Stress: compression
Movement: vertical (up)
Boundary: convergent

Question 10

What does a strike-slip fault look like? What is associated with stress, movement, and boundary of the fault?

Answer 10

Right and left going against each other, sliding. Right go up, left down
Stress: Shear
Movement: horizontal
Boundary: transform

Question 11

Which seismic wave can travel through liquids, solids, and gasses?

Answer 11

Primary waves

Question 12

Which waves move at a right angle from the wave direction?

Answer 12

Secondary waves

Question 13

Surface waves are also known as…?

Answer 13

Ocean waves

Question 14

Which waves are also called body waves?

Answer 14

Secondary waves

Question 15

Name of the famous strike-slip fault in california (caused bad earthquake in sanfransisco, 1909)

Answer 15

San Andreas Fault

Question 16

Where do earthquakes most commonly occur?

Answer 16

Usually occur at the boundaries of tectonic plates as they move

Question 17

At what location does the first motion of an earthquake occur?

Answer 17

Start an an epicenter (CHECK), which then spreads outward

Question 18

What information do travel time curves show?

Answer 18

They show the average travel times of all p-waves, s-waves, from wherever the quake occurs

Question 19

What are the depths of each focus and which depth do most occur at?

Answer 19

Shallow, intermediate, deep. Shallow could be most common???

Question 20

Difference between a seismograph and a seismometer

Answer 20

Seismometer is an instrument that detects seismic waves (usually the mass). A seismogram is the record produced.

Question 21

Difference between Richter and Mercalli Scale

Answer 21

Richter scale (Charles richter)- numerical rating system that measures magnitude (energy) determined by amplitude.
Mercalli- rates by observation during and after quake (I to XII)

Question 22

Moment magnitude scale takes what 3 into account?

Answer 22

Size of fault rupture, amount of movement along fault, rock stiffness

Question 23

What two factors determine probability of earthquake

Answer 23

Location of seismic gaps, earthquake recurrence rates???