1. Aim: How do we determine the arrival time of seismic waves? Do Now: What are some safety measures you can take during an earthquake?

2. 1.Why is the location of an earthquake important? 2.Describe the odds of an earthquakes happening again. http://science.discovery.com/videos/ what-are-the-odds-earthquake.html http://science.discovery.com/videos/ what-are-the-odds-earthquake.html -

3. How can we describe an earthquake? Earthquakes: violent shaking of the earth’s crust caused by the movement along faults Most earthquakes occur when stress builds along a zone of weakness (crack) known as faults When the stress on the rocks is greater than it can resist, the rocks will shift and break, releasing enormous amount of energy in seismic waves.

4. Activity – Earthquake Features Using the vocabulary terms on the board, identify the earthquake features on the diagram labeled A, B, C and D. After you identify the earthquake features, write the description of each term onto your worksheet. You will have 3 minutes to complete this activity.

5. Fault: break in the rock where movement occurs Focus: point deep beneath the earth where an earthquake starts and releases energy as seismic waves. Seismic Waves: earthquake waves of energy that are released in ALL DIRECTIONS Epicenter: location on earth’s surface directly above the focus. Determined by the first seismic wave reaching the earth’s surface.

6. D Fault: break in the rock where movement occurs Focus: point deep beneath earth’s surface where an earthquake starts and releases energy as seismic waves. Seismic Waves: earthquake waves of energy that are released in ALL DIRECTIONS Epicenter: location on earth’s surface directly above the focus. Determined by the first seismic wave reaching the earth’s surface.

7. How do we measure an earthquake? Seismograph: is an instrument used to detect (measures) seismic waves Seismogram: is a piece of paper that records seismic waves

8. 1.Sam arrived at a party at 7:10 pm. He had to walk 5 miles and it took him 25 minutes to arrive at the party. Determine the time Sam left his house? 2. A party began at 05:50:30 pm. Patty was at the party waiting for Sally. It took Sally 4 minutes and 15 seconds to travel 7 miles, to get to the party. Determine the time Sally arrived at the party? Why was Patty waiting? 3. How can we apply this logic to understand how seismic waves travel in the earths crust? (remember they travel at different speeds). Where is the Party??? Key 00:00:00 Hr:min:sec 60sec=1min 60min=1hr 5 miles 7 miles

9. How do we define the following: the time it takes a P or S-wave to travel a given distance how far the earthquake occurred the time it takes a seismic wave to reach the seismic station 1. Travel Time- 2. Epicenter Distance- 3. Arrival Time-

10. How do we find the Travel Time? Q1. The epicenter of an earthquake is located 2,800 kilometers from a seismic station. Approximately how long did the P-wave take to travel from the epicenter to the station? Q2: The epicenter of an earthquake is located 3,600 kilometers from a seismic station. Approximately how long did the S-wave take to travel from the epicenter to the station? 5 minutes 20 seconds 11 minutes 40 seconds

11. How do we find the Epicenter Distance? Q3. Determine the approximate total distance traveled by an earthquake’s P-wave in its first 9 minutes? Q4. Determine the approximate total distance traveled by an earthquake’s S-wave in 5 minutes and 20 seconds? 5,600 km 1,400 km

12. How do we calculate the Arrival Time? Q5. A seismic station recorded an earthquake with an epicenter distance of 4,000 kilometers. If the origin time of the earthquake was 11:00 a.m., determine the time the P-wave arrived at the seismic station? Q6. A seismic station recorded an earthquake with an epicenter distance of 9,000 kilometers. If the origin time of the earthquake was 06:20:30 p.m., determine the time the S-wave arrived at the seismic station? 11:00:00 + 00:07:00 11:07:00 a.m. 06:20:30 + 00:22:20 06:42:50 p.m.

13. 1.How long will it take a P-wave to travel 2,000 km from the epicenter? 2. The S-wave took 6 minutes to reach the seismic station, how far away is the epicenter? 3. An earthquake occurred at 10:00 am. The P- wave traveled 5600 km to the station. Determine the time the P-wave arrived at the station?

14. D