Exploring the World's Volcanoes: A Laboratory Exercise

Laboratory Exercise 4: Volcanoes Volcanoes are one of Earth’s more spectacular geologic phenomena. Volcanoes can be awe-inspiring, terrifying and in many cases, dangerous. The discrepancy between the types of eruptions often dictates our perception of volcanoes. The economy of the Hawaiian Islands thrives on tourism directed to the spectacular beauty of the island chain and the relatively peaceful erupting lava fountains on the big island of Hawaii. Many of the more scenic mountains on Earth are of volcanic origin. Some of these mountains are still actively erupting volcanoes, whereas others are long dormant. In this laboratory exercise you will use Google Earth to visit volcanoes around the world. Some of these will be active volcanoes such as Mt. Etna, whereas others will be cinder cones or shield volcanoes. The shape of a volcano gives us evidence to interpret they type of magma that formed the volcano. By comparing the shape of the volcano with its location relative to plate boundaries, we are able to make inferences concerning the magma type and explosiveness of expected eruptions. When this information is integrated with the distribution of human population centers, we can begin to assess the risk posed by volcanoes to human property and lives. Learning Objectives After you have completed this laboratory exercise, you should be able to: 1. Identify the generalized types of volcanoes based on their shape 2. Make inferences concerning magma type and explosiveness 3. Explain the dangers associated with each eruptive style 4. Assess potential danger to human life and property for selected volcanoes Exercise A: Major Generalized Types of Volcanoes Shield Volcanoes Shield volcanoes are named for their gently sloping sides that result from the extrusion of low viscosity basaltic lava. The largest shield volcano on Earth is Mauna Loa that forms part of the Big Island of Hawaii. Mauna Loa extends some 30,085 feet from its base on the ocean floor to its summit. Only 13,677 feet of Mauna Loa is above sea level. Other important shield volcanoes include the Canary Islands, Iceland, Galapagos Islands, Easter Island, Sierra Grande, New Mexico, Mt. Wrangell, Alaska, Mt. Washington, Oregon, Payún Matrú, Argentina, and Olympus Mons on Mars. Olympus Mons, is some 80,000 feet tall and 300 miles wide at its base, a size that dwarfs shield volcanoes on Earth. Figure 1. Schematic profile of a Hawaiian shield volcano from Tarbuck et al., 15 th ed. 1

Figure 2. Lava fountain from Kilauea, Hawaiian Islands. This spectacular eruption ceased in the early 1980s. Figure 3. Diagram comparing scales of different volcanoes. A. Profile of Mauna Loa, Hawaii, the largest shield volcano and tallest mountain (above base) on Earth. B. Profile of Mt. Rainier, Washington. C. Profile of Sunset Crater, Arizona, a typical cinder cone. Notice how Mt. Rainier dwarfs Sunset Crater and how Mauna Loa is much taller and wider than Mt. Rainier. Figure 6.13 from Tarbuck et al., 15 th ed. 2

Figure 4. NASA image of Olympus Mons on Mars with the outline of Arizona superimposed. This huge shield volcano would stretch the distance between Stillwater, OK and Amarillo, TX. One reason Olympus Mons is much larger than shield volcanoes on Earth is that the surface of Mars does not have moving tectonic plates. If the Pacific Plate on Earth were stationary, all of the lava that formed the Hawaiian Islands and the seamounts to the north could have accumulated as one large volcano. Figure 5. Sierra Grande peak near Capulin, New Mexico is a classic shield volcano with gently sloping sides. 3

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Composite Volcanoes Composite or stratovolcanoes are the tall steeply sloping cones that are commonly featured in images of the quintessential volcano. Many images in books or magazines articles concerning dinosaurs will feature a smoking composite volcano as background. Shield volcanoes owe their shape to alternating layers of lava and tephra (cinders and ash) produced by eruptions. Important and famous composite volcanoes include Fujiyama, Japan, Cameroon, Cameroon, Kilimanjaro, Tanzania, Citlaltépet, Mexico, Rainier, Hood, St. Helens and Adams, Washington, Mayon and Pinatubo, Philippines, Ararat, Turkey and Eyjafjallajökull, one of many unpronounceable volcanoes in Iceland. Famous historical composite volcanoes include Krakatoa and Tambora in Indonesia, Pele in Martinique, and Etna, Vesuvius and Stromboli in Italy. Figure 6. Schematic diagram of composite or stratovolcano with cone constructed of layers of pyroclastic material such as cinders, bombs and ash that alternate with lava flows. These volcanic cones are steep-sided and reach high elevations above the surrounding countryside. As a result, they are often snow-capped mountains. Figure is from Tarbuck et al., 15 th ed. 4

Figure 7. Mt. Rainier, a currently dormant composite volcano located some 33 miles southeast of Tacoma, Washington. Figure 8. Mt. Etna on the Italian island of Sicily providing another spectacular nighttime eruption. Etna has erupted for hundreds of thousands of years. Since man has sailed the Mediterranean Sea, Mt. Etna has served as a natural navigation beacon. 5

Figure 9. Mt. Fujiyama, the quintessential composite volcano with a snow-capped summit. City of Fuji in foreground. Cinder Cones Cinder cones are the most common type of volcanic eruption on Earth. These small cones (typically <1500 feet tall) are composed almost entirely of cinders and small bombs. Cinder cones often have accompanying basaltic lava flows that emanate from the base of the cone. Famous cinder cones include Sunset Crater, Arizona, Capulin in New Mexico, Parícutin in Mexico and Lava Butte in Oregon. Figure 10. Actual cinder cone and schematic. Cinder cones are small accumulations of mostly cinders (scoria) and typically have associated basaltic lava flows. Figure is from Tarbuck et al., 15 th ed. 6

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Figure 11. Mt. Capulin in the Clayton-Raton volcanic field, northeastern New Mexico. Capulin Volcano National Monument is a popular tourist destination that offers an exciting drive up the cone and spectacular views of the inspiring New Mexico landscape. Using Google Earth, visit the following volcanoes around the world by searching for the name. Note the latitude and longitude of the featured volcano and record the country where the volcano is located. Once you have located each volcano, examine the style of cone and classify it as a shield volcano , composite/stratovolcano or cinder cone . If the type of cone is not readily apparent from Google Earth, research the volcano by name. 1. Mount Capulin: Latitude __35.3642____________ Longitude ____111.5040___________ Country: __United States_____________________ Type of cone___cinder one________________ 2. Mount Kenya: Latitude _____0.1521____________ Longitude __37.3084______________ Country: _____Kenya________________ Type of cone ___stratovolcano_____________ 3. Paricutin: Latitude ____19.4933___________ Longitude ____102.2514______________ Country: _Mexico_______________________ Type of cone__cinder one________________ 7

4. Arenal volcano: Latitude _10.4626________________ Longitude ___84.7032_______________ Country: ___Costa Rica____________________ Type of cone ___ stratovolcano_______________ 5. Mauna Loa: Latitude _13.2548_____________ Longitude _123.6861___________________ Country: _Philippines______________________ Type of cone ___ stratovolcano_________________ 6. Mount Nyiragongo: Latitude 1.5220 S_____________ Longitude _29.2495___________________ Country: __Congo_____________________ Type of cone___stratvolcano________________ 7. Amboy Crater: Latitude _34.5439_________________ Longitude _115.7911____________________ Country: _United States________________________ Type of cone _cinder one___________ 8. Krakatoa: Latitude ____________________ Longitude ________________________ Country: ____________________________ Type of cone_______________________ 9. Mount St. Augustine: Latitude _59.3634_________________ Longitude _153.4331____________________ Country: _United States_________________________ Type of cone_startvolcano_______________ 10. Mount Pelee: Latitude __________________ Longitude ________________________ Country: ____________________________ Type of cone_______________________ 11. Mount Pinatubo: Latitude______________________ Longitude _________________________ Country: ____________________________ Type of cone_______________________ 12. Cotopaxi: Latitude_0.8384______________ Longitude _78.6663______________________ Country: __Ecuador______________________ Type of cone__stratvolcano__________________ Exercise B: Relationship Between Volcanoes and Plate Tectonics The relationship between the distribution of volcanoes and plate tectonics is highlighted by the Ring of Fire, a phrase used to describe the numerous volcanoes around the margin of the Pacific Ocean. Composite volcanoes are a common cone type above subductions zones, but also occur within rift zones. Shield volcanoes form when mafic (basaltic) lava spews out over hot spots and rifts. Cinder cones are intracontinental volcanoes that form when mafic magma reaches the surface without reacting with continental crust. Cinder cones are small, have short-lived eruptions and often are accompanied by basalt lava flows. 8

Figure 12. Ring of Fire and the locations of important volcanic islands and continental volcanoes. Figure 13. Continental volcanic arc like the Andes Mountains along the western margin of the South American Plate. Continental volcanic arcs are made up of mostly composite or stratovolcanoes. Figure is number 37E from Tarbuck et al., 15 th ed. 9

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Figue 14. Convergent oceanic plate volcanism forms composite/stratovolcano-dominated islands such as Japan, Phillippines, and Aleutian Islands. Figure is number 37A from Tarbuck et al., 15 th ed. Figure 15. Intraplate volcanism associated with a hot spot is responsible for the Hawaiian Islands and the line of seamounts extending to the northwest of the islands. These features are the result of the northerly movement of the Pacific Plate over the stationary hot spot. The only active volcanism in the Hawiian Islands is the southernmost island known as Hawaii or the Big Island. Subsea eruption is occuring to the southeast of Hawii and someday will form a new island. Figure is number 37C in Tarbuck et al., 15 th ed. 10

Figure 16. Continental rifting allows magma to reach the surface along fractures or faults. If the magma does not react with continental crust during ascent to the surface, shield volcanoes or cinder cones will form. If the rising magma reacts with the crust it becomes more silica-rich and composite or stratovolcanoes will form. Figure 17. Oceanic rifting and associated volcanism. Basaltic lava and cinders are typical of eruptions on the island of Iceland where inset photograph shows eruption adjacent to the lights of a community. However, intermediate magma also lies beneath Iceland, forming composite or stratovolcanoes such as Hecla. Figures 16 and 17 from Tarbuck et al., 15 th ed. 11

Plotting the locations of famous volcanoes using latitude and longitude In this section of the laboratory exercise, the locations of the volcanoes in Part A will be plotted on Figures 18 and 19. Figure 18 allows plotting the latitude and longitude coordinates of the volcanoes of interest, whereas Figure 19 provides locations of major plate boundaries. Plot volcanoes from Part A on Figure 18 and then use Figure 19 to determine if each volcano is associated with a (1) convergent, (2) divergent or (3) transform plate boundary, or if the volcano is an (4) intraplate volcano. Figure 18. Lines of latitude and longitude with outline of continents and larger islands. Plot locations of volcanoes on this map using the latitude and longitude coordinates from Part A. Red circle is the location of example volcano Skjaldbreidur. 12

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Figure 19. Principal types of plate boundaries, major tectonic plates and earthquake activity associated with the “Ring of Fire” along the Pacific Ocean. Use this figure to assign a plate tectonic setting for each volcano in Part A. The 4 settings are (1) convergent zone, (2) transform fault zone, (3) divergent zone (Mid-oceanic ridge or continental rift) or (4) intraplate. Give the plate tectonic setting and the plate(s) involved. Red circle is the example Skjaldbreidur. a. Example volcano – Volcano Skjaldbreidur in Iceland is a shield volcano at 64 o 24’ 33.5”N and 20 o , 45’ 9.2”W. Volcano Skjaldbreidur: Plate tectonic setting divergent (mid-oceanic ridge) Plates involved North American and Eurasian 1. Mount Capulin: Plate tectonic setting ___________________________________________ Plates involved ________________________________________________ 2. Mount Kenya: Plate tectonic setting _divergent (mid-oceanic ridge) _____________________________ Plates involved __transform_________________________________________ 3. Paracutin: Plate tectonic setting transform_______________________________________ Plates involved ____North America, pacific, fallon___________________________ 13

4. Arenal volcano: Plate tectonic setting __convergent zone____________________________________ Plates involved _____caribbean plate______________________________________ 5. Mauna Loa: Plate tectonic setting ___________________________________________ Plates involved ________________________________________________ 6. Mount Nyiragongo: Plate tectonic setting _divergent and convergent______________________________ Plates involved __African plate__________________________________________ 7. Amboy Crater: Plate tectonic setting _transform_______________________________________ Plates involved _____North American____________________________________ 8. Krakatoa: Plate tectonic setting ___________________________________________ Plates involved ________________________________________________ 9. Mount St. Augustine: Plate tectonic setting __convergent____________________________________ Plates involved ____North American Pacific______________________________ 10. Mount Pelee: Plate tectonic setting ________________________________________ Plates involved ________________________________________________ 11. Mount Pinatubo: Plate tectonic setting ___________________________________________ Plates involved ________________________________________________ 12. Cotopaxi: Plate tectonic setting _convergent plate_____________________________________ Plates involved __South American_______________________________________ Part C: Volcanic hazards Volcanic eruptions are hazardous to most life forms including humans. Eruptions and associated flows and landslides can devastate anything in their path. Most volcanic hazards are associated with composite volcanoes because they generate columns of hot ash, pyroclastic flows, lahars and explosive force eruptions. These hazards are enhanced by the steep sides of composite cones as gravity causes the high-velocity downslope movement of ash, pyroclasts, nu’ee ardente, lahars and gases. Other styles of eruptions have hazards. The “gentle” eruptions of Kilauea on Hawaii are accompanied by dangerous gases and advancing lava flows destroy everything in their paths. 14

In this section, volcanic hazards are matched to volcano type and famous/infamous eruptions examined. Using your text or other sources find the word or phrase that matches the following short statements. Some words or phrases may be used more than once. Most can be found in the preceding paragraph or Figure 6. 1. Mixture of hot gases and incandescent ash and small lava fragments: _pyroclastic flows_________________ 2. Mudflow of ash, pyroclasts and water (either rain or melted snowpack): __Lahar_______________________ 3. The most voluminous tephra that often is suspended in air for days: ___pyroclastic flows_________________ 4. Masses of solid rock > 64 mm (2.5 inches) propelled into the air: _Lahar______________________________ 5. Giant wave generated when volcano collapsed into the ocean: __tsunami______________________________ 6. Sulfur dioxide and carbon dioxide: _shield volcano_________________________________________ 7. Slow-moving rivers or masses of molten rock: __shield volcano__________________________________ 8. Low pH precipitation formed by combining sulfur dioxide and water: __composite volcano_____________ 9. Explosive eruption out the side of volcano that flattens trees: __pyroclastic flows______________________ Famous/Infamous Eruptions For the following historical eruptions and population centers involved, give the date and location of the volcano, type of volcano and the primary hazards involved with the eruption. 1. Mt. Pele’e. Date ___1932__________ Location __martinqique______________________ Type of volcano_ startvolcano___ Primary hazard (s) that cause destruction __2 pyroclastic flows_ 2. Pompeii. Date _Aug. 24, 79____________ Location _Southern Italy______________________ Type of volcano _startvolcano___ Primary hazard (s) that cause destruction __pyroclastic flows, lahar_ 3. Mt. St. Helens. Date ___1831____________ Location _Washington State______________________ Type of volcano _stratovolcano_____________ Primary hazard (s) that cause destruction _lava flows, lahar, pyroclastic flow__________ 4. Herculaneum. Date _79 CE____________ Location _Italy_____________________ Type of volcano _pyroclastic & lava flows_____________ Primary hazard (s) that cause destruction ________________ 15

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Current volcanic hazards. Using the Smithsonian Institution Global Volcanism Program http://volcano.si.edu determine where current or potential volcanic eruptions are generating hazards. List four volcanoes, their latitude and longitude, country where located, cone type and principal hazard. 1. Name __Erebus___________________________ latitude __77.5293__________________longitude_167.1523________________ Country __Antarctica________________ Cone type ___stratovolcano___________________________ Principal hazard ___lahars_________________________________________________________________ 2. Name __Heard___________________________ latitude __53.018___________________longitude_73.5042______________ Country _Australia_________________ Cone type ___stratovolcano___________________________ Principal hazard __lava flows______________________________________________________________ 3. Name __Etra Ale___________________________ latitude __13.6________________longitude__40.67_____________ Country _Ethiopia__________________ Cone type _Shield _________________________________ Principal hazard __lava flows_____________________________________________________________ 4. Name __Saunders___________________________ latitude __58.7________________longitude_26.483______________ Country __United kingdom______________________ Cone type __stratovolcano______________________________________ Principal hazard _lahars____________________________________________________________________ Part D. Assessing the Risk: Volcanoes near Population Centers 16

Figure 20. Terrain map of the Mt. Fujiyama area, Japan. Over 660,000 people live in the municipalities of Numazu, Fuji, Fujinomiya, and Gotemba. Figure courtesy of Google Map. 17

Figure 21. Location of Mt. Vesuvius with respect to the modern city of Naples, Italy and the ancient Roman cities of Herculaneum (yellow star) and Pompeii (red star). Naples has more than 990,000 inhabitants. Figure 22. Terrain map of the Seattle-Tacoma Washington area, including Mr. Rainier National Park. Some 900,000 people live in the Seattle-Tacoma area, with more than 200,000 in Tacoma alone. 1. What volcanic risks would an eruption of Mt. Fujiyama pose to the population in the Numazu, Fuji, Fujinomiya and Gotenba population centers? a. tsunamis b. ash fall c. lahars d. bombs e. b and c 2. The prevailing summer winds in Tokyo, Japan are almost directly from the south. If Fuji erupts in the summer, is there much of a risk for ash accumulation in Tokyo with its population of 9.3 million people? a. yes, because Tokyo is north of Mount Fujiyama b. no, because Tokyo is mostly to the east of Fujiyama c. no, because Fujiyama is not expected to produce much ash d. yes, ash is a major product of shield volcanoes 3. Both Pompeii and Herculaneum were destroyed by Vesuvius. If Vesuvius erupts again, what are the main risks to Naples? a. lahars b. bombs c. lava flows d. ash and pyroclastic surges 18

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4. Tacoma, Washington it far enough away (30+ miles) from Mt. Rainier to be safe from volcanic blasts, but what could reach the city, should Mt. Rainier erupt? a. bombs b. pyroclastic flows c. lahars d. rock avalanches When the laboratory exercise on volcanoes is completed, please submit it to Canvas or put a hard copy in Dr. Puckette’s mailbox in NRC 105. 19

Laboratory Exercise 4 Volcanoes

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