Geological Hot Spots. Name: Why do we believe that plates move? Observation: the Ring of Fire. Inference: What is a hot spot?

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1 Name: Geological Hot Spots SQ: Why do we believe that plates move? Observation: the Ring of Fire Inference: What is a hot spot? How fast are the Hawaiian Islands moving? First, we need to know the rate (speed = distance/time) of plate movement. Scientists usually report the rate of plate movement in centimeters per year (cm/yr). We are going to calculate the average rate of the Pacific Plate over the past ~5 million years using the age and location of three Hawaiian Islands. The Hawaiian Island Map (next page) shows the main islands in the Hawaiian Island chain. The oldest islands are the furthest to the West from the hot spot. As the Pacific Plate moves, newer islands form. Hawaii is the youngest island and it is still being formed today; thus, Hawaii is currently at the hot spot location. You have been given ages for three of the islands: Kauai, Molokai and Hawaii. With the scale on the map, you can figure out the distances between each island and the hot spot. Therefore you know how far the plate moved from the hotspot over time. This is all you need to calculate the rate!

2 a. Find the distance from the middle of Hawaii to the middle of Molokai. Fill the information in the first column of the data table. b. Multiply your value by 50 and fill the information in the second column of the data table. Complete the same procedure to determine the distance from Hawaii to Oahu and Hawaii to Kauai. c. Convert the kilometer distance to centimeters by multiplying by 100,000 and record the value. d. Calculate the rate at which the Pacific Plate moved since the formation of Molokai by dividing the distance by the age of each island. Fill the value in on your data table. Complete the same procedure to determine the rate of movement since the formation of Oahu and the formation of Kauai. e. After you have found the rates of movement since the formation of your three islands, average the numbers (add them up and divide by three) to find the average rate of the Pacific Plate. Island Distance on map in cm Distance in km (x50) Distance in cm (x100,000 to get centimeters) Age (years) Rate (Distance/Age) Molokai 1,800,000 Oahu 3,300,000 Kauai 5,600,000 Average rate (cm/yr)

3 Name: Hawaii is one of many global hotspots. Some are more noticeable than others. Each of the dots in the picture to the right represent a hotspot. The larger the dot, the more prominent. The U.S. has a very famous hotspot that some of you may have visited. It s located in Yellowstone National Park. Do you know the famous geyser? The Yellowstone Hotspot The image below shows the general movement of the North American plate as it passes over the Yellowstone hot spot during the last 16 million years. 1. Find the distance from the Yellowstone to the location labeled 1,200,000 years. Fill the information in the first column of the data table. Measure from the end of the white lines 2. Multiply your measurement value by 50 and fill the information in the second column of the data table. 3. Convert the kilometer distance to centimeters by multiplying by 100,000 and record the value. 4. Calculate the rate at which the North American Plate moved since the formation of Yellowstone by dividing the distance by the age of each location. Fill the value in on your data table. 5. Complete the same procedure for each volcanic field location to determine the rate of movement since the formation of Yellowstone. 6. After you find the rates of movement since the formation of each volcanic field, average the numbers (add them up and divide by seven) to find the average rate of movement of the North American Plate.

4 Location Distance on map in cm Distance in km (x50) Distance in cm (x100,000 to get centimeters) Age (years) 1,200, ,000 4,300,000 3,700,000 Heise VF 5,900,000 Picabo VF 9,600,000 Bruneau VF 11,900,000 Owyhee VF 13,200,000 McDermitt VF 15,500,000 Average rate (cm/yr) Rate (Distance/Age)

5 Name: Society Islands Hotspot The Society Islands are located in the South Pacific Ocean, west of Australia. The reason I chose these islands for analysis is that they are in line with another famous island chain hotspot that we have already studied. What is the famous island chain hotspot we ve already studied? What plate do both sets of islands hotspots sit on? 1. Find the distance from Mehetia to Tahiti. Fill the information in the first column of the data table. 2. Multiply your value by 50 and fill the information in the second column of the data table. Complete the same procedure to determine the distance from Mehetia to each of the other volcanic locations. 3. Convert the kilometer distance to centimeters by multiplying by 100,000 and record the value. 4. Calculate the rate at which the Pacific Plate moved since the formation of Mehetia by dividing the distance by the age of each location. Fill the value in on your data table. Complete the same procedure to determine the rate of movement since the formation of Mehetia. 5. After you have found the rates of movement since the formation of each Volcanic location, average the numbers (add them up and divide by seven) to find the average rate of the Pacific Plate. Location Distance Distance in km Distance in cm Age (years) Rate (Distance/Age) on map (x50) (x100,000 to get in cm centimeters) Mehetia 0 Tahiti 1,000,000 Moorea 1,500,000 Huahine 2,520,000 Raiatea 2,600,000 Tahaa 3,000,000 Borabora 3,600,000 Maupiti 4,500,000 Average rate (cm/yr) 6. How does this analysis compare to the Hawaian Island hotspot analysis? Are they similar or different? Why? 7. Are the Hawaian Islands hotspot and Society Islands hotspot parallel? 8. On the back, color the convergent subduction boundaries of the Pacifc plate blue. 9. On the back, color the divergent boundaries of the Pacific plate red. 10. On the back, color the transform boundaries of the Pacific plate yellow. 11. Using the data obtained from the Hawaian Island and Society island hotspots, draw arrows in the direction of plate movement over each hotspot.

6 12. Compare the direction of movement over the two hotspots to the location of the subducting side of the Pacific plate. Does the direction match the locations? Why or why not? 13. Along the eastern side of the pacific plate, sits a divergent boundary. Why would you find this type of plate boundary here when the western side is a subducting plate?