Lab 9 Walker

Colorado Online @ Astronomy 1110 Lab 9 T RENTON W ALKER O CTOBER 20, 2023 A STRONOMY 1110 L AB 9: H OT S POT V OLCANISM I Measuring Plate Motion In this section, you’ll use a map of the Hawai’ian Islands and their connected chain of seamounts to measure the motion of the Pacific Plate over the last 60 Myr or so. Figure 1: Map of the Hawai'ian Islands and the connected seamounts. The red spot marks the location of Kilauea. Contours show elevation or depth of water. (Modified from an original image by the USGS) 1. Print out the Lab 9 Emperor Seamounts map attached to the lab folder. If you absolutely can’t print out the map, open the document on your computer, making sure the View is at 100%. 2. Use your ruler with the map in Figure 2 to measure the distance in centimeters from Kilauea to each volcano listed in the table below. Record your results in the column labeled “Distance from Kilauea” in the table below. Be sure to measure along the island chain rather than taking a straight-line measurement. a. If you are able to print the map, sign and date it, show your rule placed on the map and photograph the two. Insert photo below. Page 1

Colorado Online @ Astronomy 1110 Lab 9 b. If you can’t print the map out have it up on your screen, show your ruler next to it and your Student Information card. Insert photo below. Volcano Name Distance from Kilauea (cm) Distance (km) Estimated Age (Myr) Kilauea 0 0 0-0.4 Maui .8 240 1.32 + 0.04 Lanai 1 300 1.28 + 0.04 Page 2

Colorado Online @ Astronomy 1110 Lab 9 d. 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 0 5 10 15 20 25 30 35 40 45 50 f(x) = 0.01 x − 1.87 Estimated Age Vs. Distance, Walker Distance (km) Estimated Age (Myr) 5. Now repeat your measurement process for the volcanoes within the Emperor Seamounts. Measure the distance in centimeters from Yuryaku Seamount to each of the other volcanoes specified in the table. Record your results in the column labelled “Distance from Yuryaku” in the table below. Volcano Name Distance from Yuryaku (cm) Distance (km) Estimated Age (Myr) Yuryaku Seamount 0 0 43.4 + 1.6 Ojin Seamount 2.7 810 55.2 + 0.7 Jingu Seamount 3 900 55.4 + 0.9 Nintoku Seamount 4.3 1290 56.2 + 0.6 Suiko Seamount 7.8 2340 59.6 + 0.6 6. Repeat your scaling process to convert the distances in centimeters to real-world distances in kilometers. Record the resulting distances in the “Distance” column. 7. Use graphing software (Excel, Google Sheets, etc.) to create a graph of Estimated Age (y- axis) versus Distance in km (x-axis) for the volcanoes in the Emperor Seamounts. Be sure your graph is a scatter plot. a. Title your graph “Estimated Age versus Distance, Your Last Name ”, add titles with units to the axes. b. Fit a straight line to the data in your graph. Show the slope of your fit on the graph. Slope=0.0059 c. The best fit line connects the distance between islands to their ages. This means we can use it to work out the rate of motion of the Pacific Plate. Divide 0.1 by the slope of the line to find the speed of motion in cm/yr. Show your work. .1/.0059= 16.949 cm/yr Page 4

Colorado Online @ Astronomy 1110 Lab 9 d. 0 500 1000 1500 2000 2500 0 10 20 30 40 50 60 70 f(x) = 0.01 x + 48.5 Estimated Age Vs. Distance, Walker Distance (km) Estimated Age (Myr) 8. Examine the map along with your answers to #3b and #6b. Has the speed or direction of motion of the Pacific Plate changed in the past 60 Myr? In what way? What evidence leads you to these conclusions? The speed within the Emperor Seamounts is faster than the speed of the Hawaiian Ridge. The Age in Myr for the Emperor Seamounts is older than the Hawaiian Ridge. The movement of the Emperor Seamounts is steeply northwest and the Hawaiian Ride is more linear to the west. The first group of volcanos are moving at a slower rate than the older volcanos were. There is also a less dramatic shift from volcano to volcano. This evidence is brought by the speed of motion calculation along with a visual of the map. Conclusion: This exercise was to compare the Age and Distance of different islands to discover the rate of movement of the islands. This exercise also shows a more dramatic shift from the older islands to the newer islands. This evidence can suggest the shift of plates in the Earth over time. References: Astronomy 2E . Openstax, 2022. Page 5