Unit V Volcanoes Name: California Geology Questions 1-9 Figure 1 is a shaded relief map from the USGS showing the area surrounding Mt. Shasta. Mt. Shasta itself is in the center of the map. Note that there is a scale bar in the bottom left hand corner. The length of the green line corresponds to 5 miles on the map. Additionally, the elevation at the orange dot is 13900 ft and at the yellow dot is 6080 ft. Figure 2 is a photo from the USGS showing rocks representative of the type you would find at Mt. Shasta. 5 mi Figure 1 Figure 2 Q-1 Draw a line outlining the extent of this volcano on Figure 1. Q-2 Use the scale bar to determine approximately how wide (in miles) Mt. Shasta is at is widest point. miles Q-3 Determine what the total relief of Mt. Shasta is. (Relief is defined as the difference in elevation between two points.) feet Q-4 What type of volcano is Mt. Shasta? (This was discussed in the tutorial) (circle one) cinder cone shield volcano stratovolcano Q-5 Recalling the lava chemistry discussion and looking at the coloration of the rocks in Figure 2, do you think that the lava that created these rocks was mafic, andesitic, or felsic?
Q-6 Recalling the lava behavior discussion and using your answer from Q-5, will the eruption be violent or gentle? Q-7 Using your answer from Q-5, and knowing that mafic lava produces basalt, andesitic lava produces andesite, and felsic lava produces rhyolite, name the rock in Figure 2. Q-8 Look at your answers from Q-4 and Q-7. From what you learned in Unit V s discussion, do the answers make sense? Briefly explain. Q-9 Draw a cross section showing how Mt. Shasta forms with regards to plate tectonics. Be sure to label the plate names and the type(s) of crust involved. Also briefly explain how the lava that erupts from Mt. Shasta forms.
Questions 10-18 Figure 3 is a Digital Orthophoto Quad (DOQ) from the USGS showing one of the cinder cones at the Cima Volcanic Field. Note that there is a scale bar in the bottom left hand corner. The length of the green line corresponds to 1 mile on the map. Additionally, the elevation at the orange dot is 3840 ft and at the yellow dot is 3650 ft. Figure 4 is a photo from the USGS showing rocks from the Cima Volcanic Field. 1 mi Figure 3 Figure 4 Q-10 Draw a line outlining the extent of the volcano on Figure 3. You can see (especially on the south side of the volcano) where lava has run out over the landscape. Go ahead and include this area in your outline. Q-11 Use the scale bar to determine approximately how wide (in miles) this cone at Cima is at its widest point (excluding where the lava has flowed away from the cone). miles Q-12 Determine what the total relief of this cone at Cima is. (Relief is defined as the difference in elevation between two points.) feet Q-13 Recalling the volcano discussion, what type of volcano is found at the Cima Volcanic Field? (circle one) cinder cone shield volcano stratovolcano Q-14 Recalling the lava chemistry discussion and looking at the coloration of the rocks in Figure 4, do you think that the lava that created these rocks was mafic, andesitic, or felsic?
Q-15 Recalling the lava behavior discussion and using your answer from Q-14, will the eruption be violent or gentle? Q-16 Using your answer from Q-14, and knowing that mafic lava produces basalt, andesitic lava produces andesite, and felsic lava produces rhyolite, name the rock in Figure 2. Q-17 Look at your answers from Q-13 and Q-16. From what you learned in Unit V s discussion, do the answers make sense? Briefly explain. Q-18 The Cima Volcanic Field is not formed at a plate boundary. Describe what is happening that causes volcanoes to form here. Be sure to explain where the lava comes from.
Questions 19-20 Use figures 5 and 6 to answer Q-20. Both images are from the USGS. Figure 5 Figure 6 Q-19 Looking back at your answers for Q-2 through Q-7, and Q-11 through Q-16, discuss the differences between the type of volcanoes found in the Cascades Province (represented by Mt. Shasta) and Mojave Province (represented by Cima). Q-20 Which figure is an image taken of Mt. Shasta? (circle one) Figure 5 Figure 6
Questions 21-23 Figure 7 shows the location of Mt. Shasta (from Q-1 through Q-9) and the Cima Volcanic Field (from Q-10 through Q-18). Figure 8 shows the population density throughout California. Both images are from the USGS. Mt. Shasta Figure 7 Figure 8 Q-21 Use figures 7 and 8 to determine what the population density is in the Mt. Shasta area. persons per square mile Q-22 Use figures 7 and 8 to determine what the population density is in the Cima area. persons per square mile Q-23 Pretend that you are the director of California s Geologic Hazards Division. You have been assigned the job of determining what areas would suffer the greatest loss of life due to a volcanic eruption. Thinking about population density AND the violence of potential eruptions at each of these locations, determine where you recommend the greatest precautions be taken to protect human life in the event of a volcanic eruption: the Cima Volcanic Field area or the Mt. Shasta area. Explain your answer.