Locating the Epicenter

1. Start here Locating the Epicenter Seismic Waves Seismogram Measuring Lag Time Finding the Epicenter

2. Seismic Waves There are three seismic waves Video of P-wave and S-wave Continue to Seismogram

3. P-Wave and S-Wave Movement Back

4. How the P and S Waves Move Back to Seismic Waves

5. How the L Wave Moves Back to Seismic Waves

6. Seismogram • The picture with the squiggly line is called a seismogram • It measures how big the seismic waves are • The seismogram is a piece of paper located on seismograph • A seismograph measures the intensity of the earthquake at a certain location • It does this by having a weight hold a pen as the earth shakes, the pencil stays still as a squiggly line is created • The more shaking the bigger the lines • The picture to the right is a seismograph Let’s see how we use this

7. Seismogram This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter.

8. How would you find the distance from the epicenter? • A. Locate the how long the P-Wave shakes the seismogram. • B. Find when the S-wave arrives, then the P-wave, and find the lag time between the two. • C. Find when the P-wave arrives, then the S-wave, and find the lag time between the two. • D. HELP!!

9. I AM SORRY THAT IS INCORRECTTRY AGAIN This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter.

10. This May HelpTRY AGAIN This is when the S-wave arrives This is when the P-wave arrives The difference in time between when the P-wave arrives and when the S-waves arrives, also know as lag time. This is important because it will tell you how far away you are from the epicenter.

11. That’s CorrectLets Try Another Question N E X T

12. Which One of These Lag Tables Is Correct? A. • B.

13. That is Incorrect A. • B. This is one should be 1 Minute This one should be 5 minutes

14. Correct!Now Let’s See How to Use Your Lag Time to Locate the Epicenter. Let’s move on I do not understand . 1st Step – Figure out the size of the lag time. Let’s use 1 minute as an example. 2.This is where the lag time is one minute 2nd Step – Find where the P-wave and S- Wave have the measurement of the lag time. 3rd Step - find the distance below. 3. Your distance is about 300 miles 1. This is how big one minute is This graph is available at bryonspicci.sslpowered.com

15. Now Let’s See How to Use Your Lag Time to Locate the Epicenter. Let’s move on I do not understand . 1st Step – Figure out the size of the lag time. Let’s use 1 minute as an example. 2.This is where the lag time is one minute 2nd Step – Find where the P-wave and S- Wave have the measurement of the lag time. 3rd Step - find the distance below. 3. Your distance is about 300 miles 1. This is how big one minute is This graph is available at bryonspicci.sslpowered.com

16. Introduction to Finding the Epicenter

17. Now You Try Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com

18. That is IncorrectUse This Hint and Try Again Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com

19. That is IncorrectHere is Another HintTry Again Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com

20. That is IncorrectThis is Your Final Hint Let say that at your location the P-wave arrives at 9:30 and the S-waves arrives 9:33, how far are you away from the epicenter? A. 9000 900 B. 1200 C. 1000 D. 900 This graph is available at bryonspicci.sslpowered.com

21. That’s CorrectLets Move on N E X T

22. Here Are Our Three Locations Chicago New York Washington, DC

23. The Epicenter is Where the Circles Meet Washington, DC is 900 miles awayclick on it New York Chicago New York is 1200 miles away click on it Chicago is 1900 miles away Click on it Washington, DC Click here to take the quiz. I think I need more help before taking the quiz This is epicenter!

24. Epicenter Quiz Correct Answers Write the answer in the box to the right. B C D A 3 • When locating the epicenter, the first thing someone must do is… • Draw three circles • Find the arrival time of the p-wave and s-wave • Find the lag time • Locate the focus • When locating the epicenter, the second thing someone must do is… • Draw three circles • Find the arrival time of the p-wave and s-wave • Find the lag time • Locate the focus • Lag time is the difference in time between the _________ and ___________. • Seismic wave and tsunami • P wave and T wave • Shake and Aftermath • P wave and S wave • After you find the distance a location is from the epicenter, you need to… • Draw a circle and find the possible locations • Draw a square and find the possible locations • Call it a day • Decide how big of a circle you need to draw around the epicenter • What is the minimum amount of locations you need to locate an epicenter? Click here when all questions have been answered