Exam (elaborations) GIZMO Earthquakes 1 Recording Station

Exam (elaborations) GIZMO Earthquakes 1 Recording Station Vocabulary: body wave, earthquake, epicenter, fault, focus, P-wave, S-wave, seismic wave, seismogram, seismograph Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Gizmo Warm-up The Earthquakes 1 – Recording Station Gizmo simulates the seismic waves released by an earthquake. To begin, look at the key on the bottom left side of the Gizmo. 1. The epicenter of the earthquake is the point on Earth’s surface closest to the focus, or origin, of the earthquake. 2. Click Play ( ) and observe the seismic waves leaving the epicenter of the earthquake. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Name: Stephanie Maurad Date: 2/22/21 1. Have you ever experienced an earthquake? If so, what did it feel like? I’ve never experienced an earthquake. 2. Earthquakes are usually caused by the sudden movement of rocks along a fault, or fracture, in Earth’s crust. The most famous fault in the U.S. is the San Andreas Fault in California. What major cities are located near the San Andreas Fault? San Francisco and Los Angeles are located near the San Andreas fault. A. What symbol represents the epicenter? The circle. B. What symbol represents the recording station? The triangle. A. What types of seismic waves are released? P and S seismic waves are released. B. Look at the Recording station detector on the upper left side of the Gizmo. What happens when the seismic waves hit the recording station? When the seismic waves hit the recording station, they’re recorded on the station detector. The P waves aren’t very effective, but the S waves are. This study source was downloaded by from CourseH on :12:09 GMT -05:00 This study resource was shared via CourseH GIZMO Earthquakes 1 Recording Station Introduction: An earthquake releases an enormous amount of energy, which passes through Earth’s interior in the form of body waves. There are two types of body waves: P-waves (primary waves) and S-waves (secondary waves). Scientists study earthquakes with the aid of an instrument called a seismograph. When seismic waves reach the seismograph, a graphical record, or seismogram, is produced. Question: How are P- and S-waves shown on a seismogram? 1. Observe: Click Play, and then click Pause ( ) after the purple P-wave hits the station. 2. Observe: Click Play, and then click Pause after the green S-wave hits the station. 3. Describe: Click Play and wait for the vibrations to stop. Suppose you were at the recording station when the earthquake hit. Based on the pattern of waves on the seismogram, what did you experience during the earthquake? 4. Explore: Click Reset, and drag the recording station closer to the epicenter. Click Play. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Activity A: Reading a seismogram Get the Gizmo ready: ● Click Reset ( ). ● Check that the Distance from the station to the center of earthquake is 860 km. A. Look at the upper right corner of the seismogram. At what time did the P-wave hit? The P-wave hit at around 155 seconds. B. What is shown on the seismogram at this time? At this time, small squiggly lines are shown on the seismograph. A. At what time did the S-wave hit? The S-wave hit at around 250 seconds. B. What is shown on the seismogram at this time? At this time, long and more intense lines are shown on the seismograph. During the earthquake, I would experience a faint shaking and then a more intense shaking for 180 seconds, or 3 minutes. A. How does this seismogram differ from the one you first investigated? This time, the P waves lasted longer and the S waves were more intense. B. What would this earthquake feel like? This earthquake would feel very obvious and worrying. This study source was downloaded by from CourseH on :12:09 GMT -05:00 This study resource was shared via CourseH Question: How can you determine how far you are from the center of an earthquake? 1. Observe: Click Play, and observe the P- and S-waves. Which waves are faster? 2. Measure: Wait until the seismogram is complete. Turn on Show time probe. Place the left (green) probe on the first P-wave, and the right (blue) probe on the first S-wave. (See example at right.) What is the Time difference (∆t) between the P- and S-waves? 3. Predict: How do you think the time difference between the first P-wave and the first S-wave will change as the distance to the epicenter increases? 4. Gather data: Place the recording station at each of the following distances to the epicenter. (Does not need to be exact.) Measure the P- and S-wave time difference (∆t) on the seismogram at each distance, and record the values in the table on the left. Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved Activity B: Distance to the epicenter Get the Gizmo ready: ● Click Reset. ● Place the recording station 300 km from the epicenter. (Does not have to be exact.) The P-waves are faster. The time difference between the P and S waves is about 40 seconds. I think the time difference will increase because the farther away the epicenter is, the longer it’ll take for the S-wave to get there, increasing the time difference. Distance (km) ∆t (s) 100 34 200 21 400 25 600 81 800 125 1000 127 This study source was downloaded by from CourseH on :12:09 GMT -05:00 This study resource was shared via CourseH 5. Make a graph: Plot your data on the graph to the right of the data table. Draw a line to connect the points in order. What does this graph show? 6. Draw conclusions: How does the time difference (∆t) between the first P-wave and the first S-wave relate to the distance to the epicenter? 7. Apply: Suppose a recording station was located 500 km from the epicenter. 8. Practice: On each of the seismograms below, label ( ) the first P-wave and the first S-wave. Estimate the time difference (∆t), and then use your graph to find the distance to the epicenter. (As in the Gizmo, each vertical line represents 50 seconds.) Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved The graph shows a positive incline in time difference as the distance increases. The farther the epicenter is, the more increased the time difference between the P and S waves will be. What will be the time difference (∆t) between the first P-wave and the first S-wave? Check your answer using the Gizmo. Were you correct? The time difference would be about 50. No. The time difference was 61. This study source was downloaded by from CourseH on :12:09 GMT -05:00 This study resource was shared via CourseHero.