Chapter 19 Study Guide Flashcards
Which wave arrives at a seismic facility first?
Primary wave (p-wave)
Where does an earthquake originate?
It originated at what is called the focus (under the ground)
What stress type pulls a material apart and which boundary is it associated?
Tension and a divergent boundary
What stress push minerals toward each other and which boundary is it associated with?
Compression, and convergent boundaries
What type of stress does the material slide past each other and which boundary is associated with it?
Shear and transform boundary
Where is the epicenter located in reference to the focus?
It is located directly above the focus (on the surface)
Explain (in detail) what the difference is between elastic/plastic deformation (not definition!)
Any stress on a material means elastic deformation (rock changed, but not permanent). After stress is greater than elastic limit, plastic deformation (changes permanent).
What does a normal fault look like? What is associated with stress, movement, and boundary of the fault?
Right hanging side sliding down, left rising up (moving apart)
Stress: Tension
Movement: Vertical (down)
Boundary: divergent
What does a reverse fault look like? What is associated with stress, movement, and boundary of the fault?
Hanging up, bottom down, coming together.
Stress: compression
Movement: vertical (up)
Boundary: convergent
What does a strike-slip fault look like? What is associated with stress, movement, and boundary of the fault?
Right and left going against each other, sliding. Right go up, left down
Stress: Shear
Movement: horizontal
Boundary: transform
Which seismic wave can travel through liquids, solids, and gasses?
Primary waves
Which waves move at a right angle from the wave direction?
Secondary waves
Surface waves are also known as…?
Ocean waves
Which waves are also called body waves?
Secondary waves
Name of the famous strike-slip fault in california (caused bad earthquake in sanfransisco, 1909)
San Andreas Fault
Where do earthquakes most commonly occur?
Usually occur at the boundaries of tectonic plates as they move
At what location does the first motion of an earthquake occur?
Start an an epicenter (CHECK), which then spreads outward
What information do travel time curves show?
They show the average travel times of all p-waves, s-waves, from wherever the quake occurs
What are the depths of each focus and which depth do most occur at?
Shallow, intermediate, deep. Shallow could be most common???
Difference between a seismograph and a seismometer
Seismometer is an instrument that detects seismic waves (usually the mass). A seismogram is the record produced.
Difference between Richter and Mercalli Scale
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)
Moment magnitude scale takes what 3 into account?
Size of fault rupture, amount of movement along fault, rock stiffness
What two factors determine probability of earthquake
Location of seismic gaps, earthquake recurrence rates???
