ANNOUNCEMENTS

1
ANNOUNCEMENTS

• Exams are getting there!
• Today
• a bit of review
• controls on intensity
• predicting (or not) earthquakes
• the relation between depth and intensity
• Outlines are on the class website

2
Clickers, of course
To be clear click first, and when everyone has
clicked, THEN please talk to your neighbor about
why you answered the way you did, and why he/she
should change his/her answer
3
The stadium at UC Berkeley has to have repairs
done every 10 - 20 years. On a north-south line,
seats, support columns, doors, etc. appear to get
pulled apart over time so that in 10-20 years
there are 3-4 (10 cm) gaps. What is the likely
cause?

1. This is a good example of the earthquake cycle
2. A major earthquake occurs there every few years
3. Fault creep along the fault that goes underneath
   the stadium
4. This is a good example of a seismic gap

4
4
1
Where is the fault in this picture?
2
3
5
What is making the street curb creep? (if you get
this wrong you are fired)

1. A left-lateral fault 3. A reverse fault
2. A right-lateral fault 4. A normal fault

6
Earthquake waves leave the focus and go out
through the earth in all directions. Which of
these is true?

1. S waves predict the existence of a liquid outer
   core
2. P waves predict the existence of a liquid inner
   core
3. The increased speed of S waves predicts the
   existence of the asthenosphere
4. S waves cannot move through the asthenosphere

7
INTENSITY
virtually untouched
destroyed

• Magnitude
• Distance from focus
• Geology! -- materials under buildings
• Ground motion

100 km (60 mi) from the epicenter
8
Foreshocks (or the earthquake itself?)Water
wellsAnimals
9
Group project depth vs intensity

• This project has two objectives
• give you a good sense of how depth and intensity
  are related
• have you understand this relation without having
  to listen to me lecture!
• And a minor third
• let those of you who swear you cant do math see
  that you can interpret information from a simple
  graph!

10
In your group assign a
leader -- whip-cracker, you need to keep everyone
on task and be sure everyone participates time
keeper -- you need to keep track of the
time reporter -- when its over, you stand up and
tell the class what you found out note taker --
you get to make the graph and write the answers
to the questions
11
In your group

• Look at the worksheet eqs, magnitude, depth,
  damage. We are using number dead/injured to
  describe intensity.
• Complete the graph and write 1-2-3 sentences to
  describe how those three parameters are related
• Answer the question about likely depth to the
  eq in China
• Answer the question about your landing site on
  planet Bling
• Put the four names of your group members on the
  graph/answer paper, with who did what job

12
c a s u a l t i e s
500
Depth to earthqu a ke
450
400
350
300
250
200
150
100
50
0
none few-15 50 100s
1000s 10,000s 100,000s
Number dead or injured Intensity
13
c a s u a l t i e s
500
Depth to earthqu a ke
450
400
350
300
250
200
150
100
50
0
none few-15 50 100s
1000s 10,000s 100,000s
Number dead or injured Intensity
14
c a s u a l t i e s
500
Depth to earthqu a ke
450
400
350
300
250
200
150
100
50
0
none few-15 50 100s
1000s 10,000s 100,000s
Number dead or injured Intensity