1. SEISMIC WAVE BASICS

2. Finding an Epicenter ESRT TABLES – GRAPH PAGE 11

3. What is an Epicenter? A point on the surface of the Earth directly above the focus of the earthquake – where the destruction (buildings / people) occurs. Focus - The point in the Earth from which earthquake waves originate – where the earthquake begins!

5. Use the data from the recording stations: Station A: San Francisco, California P-Wave arrival 3:02:20S-Wave arrival 3:06:30 What is the time difference between P and S wave arrivals?

6. Use the data from the recording stations: Station B: Denver, Colorado P-Wave arrival 3:01:40S-Wave arrival 3:05:00 What is the time difference between P and S wave arrivals?

7. Use the data from the recording stations: Station C: Missoula, Montana P-Wave arrival 3:01:00S-Wave arrival 3:03:00 What is the time difference between P and S wave arrivals?

8. Difference in arrival times: San Francisco, CA: 4:10´ Denver, CO: 3:20´ Missoula, MT: 2:00´

9. TAKE A PIECE OF PAPER, AND MARK OFF THE DIFFERENCE IN ARRIVAL TIME 2800Km 4:10

10. MOVE THE PAPER UNTIL THE TWO TICK MARKS LINE UP WITH THE P AND S CURVES WHEN TICK MARKS LINE UP, GO STRAIGHT DOWN AND READ THE EPICENTER DISTANCE EPICENTER DISTANCE OF 2800 KM

11. EPICENTER DISTANCES San Francisco, CA: 4:10 Denver, Co: 3:20 Missoula, MT 2:00 2,800 km 1,100 km 2,000 km

12. Recording Board Difference in arrival times: San Francisco: 41:0 2,800 km 1,000 2,000 3,000 4,0005,000 Line your compass up to the EXACT distance on the scale. Use the metric side (cm) beginning from zero. 0

13. .. 2800 km 2000 km 1100 km

14. Compare your answer to the historical record Missoula Denver San Francisco X Syracuse