Roy G Biv HW due 4/22/14 Please view the slideshow. You may complete the virtual lab on the website on the following slide if you’d like (do the reading and have fun you don’t have to do the questions . This activity is not required but is fun!) The purpose of this slide show is just to familiarize you with the steps of locating an epicenter. Complete the time subtracting and epicenter distance tasks on a separate sheet of paper. (this activity is required) YOU MUST SEE THE ENTIRE POWERPOINT and know the steps, so that you can do the activity in class on Wednesday!

Pangea Virtual Lab Click the link below and complete the virtual lab http://www.glencoe.com/sites/common_assets/science/virtual_labs/ES11/ES11.html

Finding Epicenters

S wave is always the bigger # so it always goes on top 29 m +60 S wave is always the bigger # so it always goes on top X X S Wave 30m 00s - P Wave 22m 20s 7m 40 s When subtracting time, be sure to borrow (if necessary) 60 seconds as shown! Show every ridiculous step. Try the time subtraction problems on the following slides. Did you get the accepted answer?

2:33:00 2:35:30 2:35:30 – 2:33:00 = 00:02:30

2:35:10 2:39:20 2:39:20 – 2:35:10 = 00:04:10

2:32:10 2:34:00 2:34:00 – 2:32:10 = 00:01:50

NOW you try! Show ALL WORK

How to use the P & S Wave Chart

We don’t know when the EQ started. But we know how much time there was between the P&S wave arrivals. Let’s say 0:04:00 C’mon let’s say it!

We have to find a spot on the graph where P&S (careful We have to find a spot on the graph where P&S (careful!) are separated by 4:00.

Then drop straight down to see the distance to the epicenter. 2,600km

Now that we know the EQ was 2,600km away, when did it start? To travel 2,600km, a P-wave… needs 5:00 minutes

Back to the lab… The difference in arrival time for Chicago is 0:02:30. That means that Chicago is ______ km from the epicenter. 1,400

Now that we know the EQ was 1,400km away, when did it start? To travel 1,400km, a P-wave… needs 3:00 minutes

If the P-wave was detected at 2:33:00 and needed 3:00 minutes to travel it must have started at… -3:00 2:30:00

1,400km

The EQ happened somewhere on this line

The Epicenter is where all 3 circles intersect! Ta Da! x

If you get a nice epicenter, you do the VICTORY DANCE! The End