TodayToday Hand in your LAB and any other work.Hand in your LAB and any other work. Check the list in the back, if you owe Check the list in the back, if you owe

something.something. Get out a half sheet of piece of paper, Get out a half sheet of piece of paper,

PUT YOUR NAME ON IT.PUT YOUR NAME ON IT. When bell rings the quiz will start and When bell rings the quiz will start and

you will have 1 minute per question to you will have 1 minute per question to answer.answer.

Question 1Question 1 Define a focus & an epicenter.Define a focus & an epicenter.

Question 2Question 2 What are the 2 scales used to What are the 2 scales used to

measure size of EQ?measure size of EQ?

Question 3Question 3 Subtract these times:Subtract these times:

12:02:2212:02:22 - 11:50:40- 11:50:40

Question 4Question 4 What is the temperature at What is the temperature at

4000km below the surface of the 4000km below the surface of the Earth?Earth?

ANSWERSANSWERS Define a focus & an epicenter.Define a focus & an epicenter.

Focus is below ground where EQ happens

Epicenter is on the surface above focus What are the 2 scales used to What are the 2 scales used to

measure size of EQ?measure size of EQ? Mercalli & Richter

SubtractSubtract 00:11:42

Temperature at 4000kmTemperature at 4000km ~5800 oC

Steps to Find an Steps to Find an Earthquake EpicenterEarthquake Epicenter

Be careful today you need to be real Be careful today you need to be real accurate!accurate!

Steps (Steps (write this downwrite this down))1) Find P wave arrival

Find S wave arrival

2) Find Difference (S-P) Subtract

3) ESRT page 11 Use number from step 2

4) Go to map and draw circle to scale at distance

5) Repeat at least two more times

ESRT P 11ESRT P 11

Each line = __________

Each line = _________

Think back to EQ waves LAB…

Which wave is faster?

What happens as you get further away?

Step 1: Step 1: P and S wave arrivalP and S wave arrival

P-wave arrival time = ???

First big blip

S-wave arrival time = ???

Second big blip

P = 4 minutes S = 8 minutes

Step 2:Step 2:Find IntervalFind Interval

P = 4 minutes S = 8 minutes

hr : min : sec S-wave 00:08:00

P-wave -00:04:00 00:04:00 minutes00:04:00 minutes

Take the 4 minutes and open your ESRT to pg 11.

ALWAYS use hr : min : sec

Format!

Step 3:Step 3:ESRT pg 11ESRT pg 11

Find 4 minutes HERE (RED line)

1. Then, count the boxes or draw a line on scrap.

2. Then, slide the scrap or count the difference in between S & P waves

3. Read off distance on x axis

2800 km

Safety compass Safety compass

Safe? Safe? Set center point Set center point

to 0.to 0. Move arrow to Move arrow to

distance.distance. Put your finger Put your finger

on circle and on circle and pen in arrow.pen in arrow.

Draw circle from Draw circle from city data is from.city data is from. 0 1000 2000 3000Safer ?Safer ?

Be carful do NOT over turn the

screw!

Center circleCenter circle

Distance Distance sliderslider

Step 4:Step 4:Map It!Map It!

0 1000 2000 3000

Step 5: Step 5: Do it againDo it again

1) Find P wave arrival ~S wave arrival

2) Find Difference (S-P)

3) ESRT page 11 ~Use number from step 2

4) Go to map and draw circle to scale at distance

Now what??Now what??Where is the EQ?Where is the EQ?

0 1000 2000 3000

Do it againDo it again1) Find P wave arrival

~S wave arrival

2) Find Difference (S-P)

3) ESRT page 11 ~Use number from step 2

4) Go to map and draw circle to scale at distance

0 1000 2000 3000

EQ is Here

Let’s ReviewLet’s Review Step 1:

Find the arrival times Step 2:

Subtract S-P wave times (S-P interval) Look up on ESRT 11 the distance.

Step 3: Look up on ESRT 11 the distance.

Find the S-P interval on the Y-axis and then find that in between the P & S wave lines.

Step : 4: Once you have 1 distance draw circle.

Steps 5: Repeat at least 2 more times!

P-Wave travel timeP-Wave travel time This is the time it takes for the P-wave to This is the time it takes for the P-wave to

get to the recording station.get to the recording station.

It’s simple to find!It’s simple to find! Use the epicenter distance you already found.Use the epicenter distance you already found. Go to that distance on your ESRT and follow a Go to that distance on your ESRT and follow a

line up to the P-wave line.line up to the P-wave line. Follow to the left and read off the time!Follow to the left and read off the time!

Let’s tryLet’s try Subtract:Subtract:

12:00:0012:00:00 11:34:3011:34:30 01:21:10 01:21:10 -11:55:30 -11:55:30 -11:30:50 -11:30:50 -01:18:18-01:18:18

Station(City)

Arrival P-wave

ArrivalS-wave

S-P time+/-

(00:00:30)

Distance+/-

(200km)

P-wave travel time

A 11:55:30

12:00:00

B 11:30:50

11:34:30

C 01:18:18

01:21:10

NextNext1.1. Practice page Practice page 33/3433/34

Try it yourself FIRST! Then catch me for help.Try it yourself FIRST! Then catch me for help.

2.2. Then, turn to page Then, turn to page 35/3635/36Use data on board to complete the chart and find Use data on board to complete the chart and find

the epicenter!the epicenter!

3.3. Then, turn to page Then, turn to page 37-4037-40This is may be your homeworkThis is may be your homework