Earthquakes; Rock Cycle Flashcards
1
Q
scale of a earthquake
A
log factor 10
2
Q
how can we tell how much energy is generated in an earthquake?
A
- fractures
- how it moves
3
Q
What is the Mercalli scale?
A
- not about the magnitude of energy released
- not good
4
Q
What are P-waves
A
- compressional waves (like sound)
- faster
- primary
5
Q
What are S-waves
A
- transverse waves
- up and down
- do not go through fluids
- shear stress
- secondary
6
Q
what is a surface wave?
A
- motion does not depend upon distance from surface
- the same everywhere
- circular wave
- motion decreases as you go down (wave base)
- ocean
7
Q
What is wave base?
A
8
Q
A
the bigger they are the less they are
9
Q
where do earthquakes occur?
A
- plate boundaries
- mid-ocean ridge
10
Q
how do earthquakes feel at mid-ocean ridges?
A
shallow
11
Q
what is liquid faction?
A
- things turned to liquid when shaken
- sedimentary basements
- stiff at first
12
Q
what happens when an earthquake is in the ocean?
A
- water cannot support shear stress
- water displaced with surface waves (one plate goes up and the other down)
- wavelength decreases when wave base touches the floor
13
Q
when do waves break
A
1:7 ratio
14
Q
isostemic
A
bounds of weight
15
Q
A
- ocean crust getting older and denser
16
Q
A
failed rift
17
Q
what can earthquakes do?
A
tell us about the interior of the Earth
18
Q
which layer has more volume?
A
mantle
19
Q
what is epicenter?
A
surface impact
20
Q
what is focus?
A
depth
- subduction zones
21
Q
dense rocks
A
faster seismic waves
22
Q
what is the Mohorovicic discontinuity?
A
- crust and mantle
- different properties
23
Q
What are shadow zones?
A
24
Q
where do waves refract?
A
- angle
25
internal reflection
25
deeper= higher pressure = faster
- ROGH
26
what is seismic tomography?
27
what can we do to forecast earthquakes in the short term?
-
28
what can we do to forecast earthquakes in the long term?
- stress relief
- stress relocated
29
how does mountain building work?
30
what happens when you build mountains
- deform crust
- orogen
31
what happens when you deform a rock quickly?
returns to its original shape
32
what does inelastically mean?
when you deform a rock slowly over a long time, so it does not come back
33
what is a normal fault
tension hanging wall moves down relative to foot wall
34
what is a thrust fault
to pieces of a rock override each other
- not so angled
35
what is a strike-slip?
36
what is strike and dip?
strike: horizontal line that touches surface of dip: steepest like perpendicular to strike
37
what is an anticline?
dome of hill
(old rock)
38
what is a syncline?
dip of hill
(young rock)
