# Answers: Earthquake and Lab Book

Axia College Material Appendix F Week Three Lab Report: Earthquakes Answer the lab questions for this week and summarize the lab experience using this form. |Full Name | | |Date | | Carefully read pages 156-170 of Geoscience Laboratory. Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Select answers are provided for you in red font to assist you with your lab work.

Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own. Lab Questions 9. 1. Judging from the seismogram in Figure 9. 4 of the lab book, which wave appears to be the most damaging? Surface Wave 9. 3. Determine the distance to an earthquake at a station that receives P and S waves 5. 0 minutes apart. Hint: (a) Place tick marks on a scrap of paper equal to 5. 0 on the minutes axis. (b) Fit that to the horizontal separation between P and S curves. (c) Read distance directly across on the distance axis. 3,000 km 9. 4.

At this point, from the information in Figure 9. 6A, how specific can you be as concerns the location of that earthquake? Answer: The earthquake is somewhere on the circle around Seattle 9. 5. At this point, from the information in Figure 9. 6B, how specific can you now be as concerns the location of that earthquake? The earthquake is located at one of the two points where the two circles intersect. 9. 6. At this point, from the information in Figure 9. 6C, how specific can you now be as concerns the location of that earthquake? The earthquake is located at the point in Montana where the three circle intersect . 10. Using the nomogram, determine the Richter magnitude for the three earthquakes listed (see, p. 169 in the lab book). |S arrival minus p arrival |Amplitude |Magnitude | |(A) 8 seconds |20 millimeters |4 | |(B) 8 seconds |0. 2 millimeters |2 | |(C) 6 seconds |10 millimeters |3. | 9. 14. The 2002 Afghanistan earthquake measured 5. 9 on the Richter scale and killed 1,800 people. The 2001 western Washington earthquake measured 6. 8 on the Richter scale and killed only one person. Can you imagine why the huge difference in the numbers of deaths? Hint: It has to do with construction materials. The mud walls used in construction of Afghan homes could not withstand the shaking from the earthquakes whereas construction in the United States tends to be better reinforced. 9. 17.

Where is the location of that June 19 quake (to the nearest tenth of a degree latitude and longitude)? Follow the steps 1 through 4 to complete the table below (see lab book pp. 164-165). | |P arrival time |S arrival time |Difference in P & S | |LTN |3:46:45. 7 |3:46:50. 0 |4. 3 |35. 6 | |GOIL |3:46:0. 9 |3:47:17. 2 |16. 3 |137 | |POW |3:47:3:0 |3:47:20. |17. 8 |149 | 9. 17 Latitude Answer: 36. 3? Longitude Answer 90. 1 ? 9. 20. One of the curious things about the loss of life in regions surrounding the Bay of Bengal is that some 38,195 lives were lost in Sri Lanka, whereas only 2 lives were lost in Bangladesh. How could this be? It certainly couldn’t be the difference in distance. Hint: To answer this question, you should first contour the map in Figure 9. 20 (see p. 170 in the Lab book) and then follow ‘the rule. ’ Note: You do not need to submit the contour map with this report.

The path that the tsunami would travel to Bangladesh goes through much shallower water than the path to Sri Lanka. According to the rule, less energy is expended when the tsunami travels through deeper water, causing the run-up to be higher with more destruction. Lab Summary Address the following questions in a 100- to 200-word summary: • Summarize the general principles and purpose of the lab. • Explain how this lab helped you better understand the topics and concepts addressed this week. • Describe what you found challenging about this lab. • Describe what you found interesting about this lab. Write your summary here: