FOCUS ON EARTH SCIENCE (10)

Volcanoes /…iÊ Ê`i> Volcanoes are locations where magma reaches Earth’s surface They affect human and wildlife habitats 1.e, 7.b 1.d, ˆ} *ˆVÌÕÀi `i> Volcanoes and Plate Boundaries LESSON >ˆ˜ ,i>`ˆ˜} >ˆ˜Ê`i> Most volcanic …iVŽ activity occurs along plate boundaries where plates move relative to one another 1.d, 1.f, 7.g, 7.h ˆ} >ˆ˜ Volcanic Eruptions *ˆVÌÕÀi `i> LESSON and Features ,i>`ˆ˜} >ˆ˜Ê`i> …iVŽ The compo- sition of magma controls volcanic eruptions and determines the different types of lava flow and volcanic features ˆ} 2.d, 7.a, 7.b, 7.d 3*ˆVÌÕÀi Hazards of Volcanic ,i>`ˆ˜} Eruptions …iVŽ >ˆ˜ LESSON `i> >ˆ˜Ê`i> Volcanic eruptions can change human and wildlife habitats >ˆ˜ `i> ˆ} *ˆVÌÕÀi ,i>`ˆ˜} 290 …iVŽ Beautiful, but Dangerous These tourists watch a fountain of lava on the coast of Hawaii, at the Kilauea volcano The Hawaiian Islands are forming as a result of volcanic activity The Hawaiian Islands are in the middle of the Pacific Plate, far from its edges They sit above a hot spot under the Pacific Plate Volcanic eruptions create scenic landscapes as the lava is ejected from volcanoes -Vˆi˜ViÊÊ+PVSOBM Imagine you are among the tourists viewing the volcanic eruption Make a list of what you might hear, smell, feel, see, and possibly taste while watching the eruption Start-Up Activities How did these rocks form? Examine three photos of rocks or rock samples from your teacher Each of these rocks formed from lava ejected during a volcanic eruption Volcanic Features Make the following Foldable to identify volcanic features STEP Fold a sheet of paper in half lengthwise Procedure Design a chart to record the color, texture, and mass of each rock Estimate the number and size of bubbles and crystals in each rock STEP Cut along every third line of the top flap to form tabs Think About This • Infer which rock cooled the fastest and which one cooled most slowly • Predict what environmental conditions might have existed when each rock was formed 1.d, 7.e STEP Label as shown 6œV>˜ˆV i>ÌÕÀià ELA6: R 2.4 Visit ca6.msscience.com to: ▶ ▶ ▶ ▶ view explore Virtual Labs access content-related Web links take the Standards Check Reviewing As you read Lesson 2, identify and list the volcanic features on the tabs Include a sketch and information under the tabs 291 Get Ready to Read Make Predictions Learn It! A prediction is an educated guess based on what you already know One way to predict while reading is to guess what you believe the author will tell you next As you are reading, each new topic should make sense because it is related to the previous paragraph or passage Practice It! Read the excerpt below from Lesson Based on what you have read, make predictions about what you will read in the rest of the lesson After you read Lesson 2, go back to your predictions to see if they were correct Think about how the composition of magma could affect a volcanic eruption Predict how the amount of silica present in magma could affect the energy of a volcanic eruption The composition of magma is an important characteristic when attempting to predict a volcanic eruption Scientists can predict the energy of a volcanic eruption based on the percentage of silica and oxygen that is present in the magma Silica is just one of the chemical characteristics that controls the eruptive behavior of a body of magma —from page 302 Determine what other chemical characteristics control the eruptive behavior of a body of magma Apply It! Before you read, skim the questions in the Chapter Assessment Choose three questions and predict the answers 292 Target Your Reading heck the see c , d a e r e to As you you mad s n o i t c i t pred e correc r e w y e h if t Use this to focus on the main ideas as you read the chapter Before you read the chapter, respond to the statements below on your worksheet or on a numbered sheet of paper • Write an A if you agree with the statement • Write a D if you disagree with the statement After you read the chapter, look back to this page to see if you’ve changed your mind about any of the statements • If any of your answers changed, explain why • Change any false statements into true statements • Use your revised statements as a study guide Before You Read A or D Statement After You Read A or D Most volcanic eruptions occur at plate boundaries Magma rises buoyantly and exerts an upward force on Earth’s surface Scientists are able to predict when a volcano will erupt Volcanic ash is dangerous in the air and on the ground Hot spots form where two oceanic plates converge Lava flows are the most dangerous type of volcanic hazard Print a worksheet of this page at ca6.msscience.com A lava dome is filled with thick, viscous lava Lava that contains high amounts of silica can be extremely explosive Shield volcanoes are the smallest type of volcano 10 Composite volcanoes are composed of alternating layers of lava and tephra 293 LESSON Science Content Standards 1.d Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface 1.e Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions 7.b Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data Reading Guide What You’ll Learn ▼ Explain what causes volcanic activity ▼ Relate the location of volcanoes to plate boundaries Why It’s Important Understanding how volcanoes form and where they occur helps scientists predict volcanic eruptions Vocabulary volcano hot spot vent fissure eruption Review Vocabulary lithospheric plate: large, brittle pieces of Earth’s outer shell composed of crust and uppermost mantle (p 183) 294 Chapter • Volcanoes Jeremy Bishop/SPL/Photo Researchers Volcanoes and Plate Boundaries >ˆ˜Ê`i> Most volcanic activity occurs along plate boundaries where plates move relative to one another Real-World Reading Connection Maybe you’ve been outside when a hot-air balloon flew overhead When the pilot turned on the flame under the balloon, the balloon rose higher in the sky As temperature increases, particles move faster, ˆ} the air to expand and become less dense >ˆ˜ causing *ˆVÌÕÀi `i> Particles in molten rock also move faster, expand, and become less dense as the temperature increases ,i>`ˆ˜} …iVŽ What is a volcano? A volcano is a land or underwater feature that forms when magma reaches the surface of Earth Recall from Chapter that magma is molten, liquid rock material found underground and forms igneous rocks Magma rises up to Earth’s surface because its density is less than the rock through which it moves When magma rises to Earth’s surface it is called lava Volcanoes can cause the eruption of liquid, gas, or solid materials Hot gases, magma, and even solid rock particles can be explosively erupted from openings on Earth Scientists, as shown in Figure 1, study the composition of lava to better understand volcanic eruptions Figure This photo shows volcanologists collecting a sample of lava from a volcano How volcanoes form? Recall from Chapter that some of Earth’s internal heat is left over from when the planet first formed When rocks become hot enough, and pressure and other conditions are right, they can melt WORD ORIGIN What causes rock to melt? volcano from Italian vulcano; means burning mountain In order for a volcano to form, magma must first reach Earth’s surface Magma is less dense then the rock from which it melted Therefore, magma tends to rise above the denser rock The density of magma depends upon its composition, the amount of dissolved gas, and its temperature Magma also tends to be more buoyant when compared to the rocks that surround it Magma is forced to rise toward Earth’s surface because of the buoyant force pushing up on the magma Where volcanoes occur? Volcanoes are not common in all regions of Earth’s crust Volcanoes typically occur along divergent and convergent plate boundaries and hot spots, where the flow of heat from Earth’s interior is high Figure shows the locations of active volcanoes and plate boundaries on Earth Do you notice a relationship between the locations of active volcanoes and plate boundaries? Figure This world map shows that most active volcanoes are located near the edges of the plate boundaries The Ring of Fire is a belt of active volcanoes that circles the Pacific Ocean 6G8I>8D8:6C 6H>6 CDGI= 6B:G>86 :JGDE: 6IA6CI>8D8:6C 6;G>86 E68>;>8D8:6C >C9>6C D8:6C HDJI= 6B:G>86 6JHIG6A>6 6CI6G8I>86 >C9>6C D8:6C 6Xi^kZkdaXVcd Lesson • Volcanoes and Plate Boundaries 295 Convergent Plate Boundaries Recall from Chapter that when two lithospheric plates move toward each other, a convergent plate boundary forms They include areas where an oceanic plate is subducted below a continental plate or where an oceanic plate is subducted below another oceanic plate As the plate subducting below the other plate gets deep enough, it becomes hot enough to partially melt and form magma The magma is then forced up toward Earth’s surface and forms volcanoes Volcanoes that form along convergent plate boundaries tend to erupt more violently than other volcanoes Figure shows examples of convergent plate boundary landforms Figure Identify the locations of two convergent plate boundary landforms Volcanic Arcs When an oceanic plate subducts beneath a continental plate, a volcanic arc is formed A volcanic arc is a string of volcanoes that forms on land parallel to the leading edge of the continent An example of a volcanic arc is shown in Figure Island Arcs When two oceanic plates move toward each other, an island arc is formed Island arcs are long, curved strings of volcanic islands Figure shows an example of an island arc volcano Figure Volcanoes typically form at five geologic typically form at five locations Movement along geologic locations.plate boundaries and hot spots tends to Movement along plate form volcanic eruptions with boundaries and hot unique characteristics spots tends to form volcanic eruptions with unique characteristics DXZVc^X a^i]dhe]ZgZ >haVcY VgX DXZVcigZcX] KdaXVcd JeeZgbVciaZ 6hi]Zcdhe]ZgZ 6c^haVcYVgX[dgbh l]ZcilddXZVc^X eaViZhXdckZg\Z# 296 Chapter • Volcanoes =dihedi =dihedih[dgb VlVn[gdb eaViZWdjcYVg^Zh# Divergent Plate Boundaries Imagine a divergent plate boundary as a huge crack, or rift, in Earth’s surface The boundary can occur in either the ocean, as a mid-ocean ridge, or on a continent, as a continental rift Tension stresses cause the lithospheric plates to be pulled apart This pulling action forms rifts that allow magma to reach Earth’s surface through fissure eruptions In the ocean, lava flows from these rifts are cooled quickly by seawater and form new volcanic rock As more lava flows and hardens, it builds up on the seafloor Sometimes, the volcanoes rise above sea level, forming islands such as Iceland SCIENCE USE V COMMON USE rift Science Use fissure, crevasse As the lithospheric plates were pulled apart, a rift valley was created Common Use to burst open, divide The argument caused a rift between the two friends How volcanoes form at divergent plate boundaries? Heat Escapes Volcanic eruptions are one of the most noticeable signs that heat is escaping from Earth’s interior After many of thousands or even millions of years, magma reaches Earth’s surface When this magma erupts from the central, circular or oval-shaped opening of a volcano, called a vent, a cone-shaped landform develops This landform develops because lava flows out from one source in many directions As lava flows out, it cools quickly and becomes solid, forming layers of igneous rock around the vent the steep-walled depression around a volcano’s vent is the crater B^Y"dXZVcg^Y\Z DXZVcigZcX] ACADEMIC VOCABULARY source (SORS) (noun) point of origin We found the source of the loud music to be a concert 8dci^cZciVag^[ikVaaZn KdaXVc^XVgX DXZVc^X Xgjhi 8dci^cZciVaXgjhi 8dci^cZciVaa^i]dhe]ZgZ JeeZgbVciaZ 6hi]Zcdhe]ZgZ BV\bV 6iVcdXZVc^XY^kZg\ZcieaViZ WdjcYVgnb^Y"dXZVcg^Y\Z!eaViZhVgZ ejaaZYVeVgiVcYcZlXgjhi^h[dgbZY# 8%,"%(6"-,)&-( 6kdaXVc^XVgX[dgbhl]Zc dXZVc^XVcYXdci^cZciVa eaViZhXdckZg\Z# 6iVXdci^cZciVaY^kZg\ZcieaViZ WdjcYVgn!bV\bVg^hZhidi]Z hjg[VXZVii]Zg^[ikVaaZn# Lesson • Volcanoes and Plate Boundaries 297 Figure This crack formed because of a fissure eruption at a mid-ocean ridge The currents caused by this activity attract the crabs Fissure Eruptions When magma escapes from narrow and elongated cracks in Earth’s crust, a fissure eruption (FIH shur · ih RUP shunz) occurs The magma pushes out along both sides of the crack and flows smoothly Long, sheetshaped landforms develop Fissure eruptions can occur in the ocean at a divergent plate boundary They form mid-ocean ridges and new seafloor, as shown in Figure Fissure eruptions can also occur on a continent at a divergent plate boundary They form a rift and produce new crust on Earth’s surface Volcanoes Away from Plate Boundaries Some volcanoes not form along plate boundaries These volcanoes are known as hot spots, which are localized areas of high heat in Earth’s interior Scientists continue to study how hot spots form and move Figure shows an example of a hot spot Figure The Hawaiian Islands are actually volcanoes that formed over a hot spot They formed over a period of about million years @VjV^ C^^]Vj DV]j Bdad`V^ BVj^ AVcV^ @V]ddaVlZ =VlV^^ 298 Chapter • Volcanoes (t)Dr Ken MacDonald/SPL/Photo Researchers, (b)NASA/SPL/Photo Researchers Formation of Volcanoes Heat and pressure from Earth’s interior cause rock to melt and become magma Because magma is less dense than the surrounding rock, the buoyant force causes it to rise to Earth’s surface Most volcanoes form at divergent or convergent plate boundaries However, hot spots form away from plate boundaries Scientists continue to study hot spots to better understand how and why they form LESSON Review Standards Check Summarize Create your own lesson summary as you design a study web Write the lesson title, number, and page numbers at the top of a sheet of paper Scan the lesson to find the red main headings Organize these headings clockwise on branches around the lesson title Review the information under each red heading to design a branch for each blue subheading List 2–3 details, key terms, and definitions from each blue subheading on branches extending from the main heading branches ELA6: R 2.4 Using Vocabulary Complete the sentences using the correct term vent fissure eruption A cone-shaped landform develops when magma erupts from the forming a 1.d volcano Long, sheet-shaped landforms develop when a(n) pushes magma out along both sides of a crack in Earth’s crust 1.d Understanding Main Ideas Illustrate and label two types of openings from which 1.d magma erupts Organize Draw a diagram like the one below List five settings where volcanoes occur 1.e Volcanoes occur 5 Sketch the formation of a volcano Include the forces at work in Earth’s interior that cause a volcano to form and magma to flow to the surface 1.d Compare and contrast the movement of lithosphere at a mid-ocean ridge and a sub1.e duction zone Applying Science Hypothesize why volcanoes are not likely where two continental plates converge Support your answer with information from this lesson 1.e Relate the occurrence of volcanoes along the Pacific Ring of Fire to the types of plate boundaries in the region Consider the direction in which the boundaries are moving and any geologic features that affect the volcanic activity 1.e Science nline For more practice, visit Standards Check at ca6.msscience.com Lesson • Volcanoes and Plate Boundaries 299 Gases Pyrocastic Flow Lava Flow Gas Emissions ACADEMIC VOCABULARY Gases released from volcanoes can also be a silent hazard to humans and wildlife Sulfur dioxide and hydrogen sulfide gases, when mixed with water, can form acidic precipitation This precipitation can be harmful to animals and vegetation Figure 17 shows trees killed on Mammoth Mountain as a result of carbon dioxide seeping from beneath the volcano release (rih LEES) (verb) to set free from confinement We released the balloons into the gentle breeze Pyroclastic Flows Another hazard from explosive eruptions is a pyroclastic flow, which is a fast-moving body of hot gases and solids Pyroclastic flows tend to follow valleys and can devastate everything in their paths Figure 17 shows an example of a pyroclastic flow as it moves quickly down the slopes of the Soufriere Hills volcano an Montserrat Island Intensely hot gas that travels within the pyroclastic flow can contaminate the surrounding air, burning and destroying wildlife and humans WORD ORIGIN pyroclastic pyro– from Greek; means fire clastic from Greek klastos; means broken Figure 17 Predict what might happen if a city were in the path of a pyroclastic flow Lava Flows Lava flows can occur from either an explosive or quiet volcanic eruption Figure 17 shows an example of a lava flow in Hawaii Lava flows can destroy human and wildlife habitats by starting fires, destroying property and crops, and releasing smoke, which affects air quality Most lava flows move slowly enough that humans can be warned of possible dangers Lesson • Hazards of Volcanic Eruptions 315 (l)Jess Smith/Grant Heilman Photography, (c)Bernhard Edmaier/Photo Researchers, (r)Eric Kroll/Omni-Photo Communications Figure 18 Scientists from the United States Geological Survey monitor volcanoes using sensitive seismic equipment Predicting Volcanic Eruptions Volcanoes usually show signs of activity before they erupt These signs include small earthquakes, emission of gases, and changes in ground movement and temperature of the surface of the volcano This allows scientists to issue warnings about possible volcanic activity Small Earthquakes Small earthquakes can occur when magma is forced up through brittle rock Usually before a volcanic eruption, there are many small earthquakes ranging from about 1.0 to 3.0 in magnitude Figure 18 shows an example of a ground-based seismic network designed to detect earthquake activity Gas Emissions Figure 19 This infrared satellite image shows an eruption of the Augustine volcano in Alaska The volcanic ash cloud was ejected 11,500 m into the air The land and the sea around the volcano have been coated with ash Scientists collect gas emissions from volcanoes Different amounts of gases—carbon dioxide, for example—indicate how deep below the surface magma is located Changes in the type or amount of gases coming from a volcano might signal that an eruption will occur soon Identify what colors show the volcanic ash cloud Ground Movement and Temperature As magma moves toward Earth’s surface, the ground around the volcano can increase in temperature As the magma is forced up, the ground might actually begin to rise or bulge slightly Using remote-sensing devices, scientists are able to detect changes in temperature and ground movement Monitoring Volcanic Activity Even small changes in the surface of a volcano can be detected from space Scientists can closely monitor volcanic activity with the use of satellite imaging Figure 19 shows a satellite image of the movement of volcanic ash clouds as seen from space 316 Chapter • Volcanoes (t)C Neal/U.S Geological Survey, (b)U.S Geological Survey/Photo Researchers Volcanic Hazards Volcanic landforms and features range in shape and size All types of volcanoes can emit gases, solids, lava, and tephra during explosive eruptions Gas emissions, lahars, and pyroclastic flows are some hazards that result from volcanic eruptions Scientists are improving their understanding of how volcanic processes work Through technology, scientists are better able to monitor volcanic activity from space This helps them more accurately predict dangerous eruptions, which can impact human and wildlife habitats LESSON Review Standards Check Summarize Create your own lesson summary as you organize an outline Scan the lesson Find and list the first red main heading Review the text after the heading and list 2–3 details about the heading Find and list each blue subheading that follows the red main heading List 2–3 details, key terms, and definitions under each blue subheading Review additional red main headings and their supporting blue subheadings List 2–3 details about each ELA6: R 2.4 Using Vocabulary Define volcanic ash in your 2.d own words Distinguish between a pyro2.d clastic flow and a lahar Design Draw a chart like the one below List the effects of volcanic hazards on human and wildlife habitats 2.d Effects of Volcanic Hazards Understanding Main Ideas Predict the hazards to a town that is located in a valley at the base of an active volcano 2.d Name of Hazard Effects of Hazard Volcanic ash Summarize how scientists can use small earthquakes to pre2.d dict a volcanic eruption Lahar Analyze the advantages of monitoring volcanic activity with technology in space as compared to ground-based 2.d sensoring Pyroclastic flow Gas emission Lava flow Applying Science Assess the potential volcanic hazards from a glacier-topped volcano over km high Support your reasoning with 2.d specific examples Science nline For more practice, visit Standards Check at ca6.msscience.com Lesson • Hazards of Volcanic Eruptions 317 How does lava affect habitats? Volcanic eruptions can change human and wildlife habitats Scientists make models of volcanoes and their landscapes to test how lava might flow during an eruption Procedure Read and complete a lab safety form Make a volcano on an aluminum pie pan with modeling clay Include trees and buildings on the landscape Draw a topographic map of your landscape to record your results Design a procedure to test different types of materials to imitate lava, such as frosting, molasses, syrup, honey, and water Measure the same amount of each material Pour the lava from the top of the volcano Record the path, area, and distance of the lava flow on your topographic map Wash and dry the landscape Repeat with the same amount of each lava sample Analysis Describe the viscosity of each lava sample Sequence the lava flows from fastest to slowest Compare the rate of lava flow to the viscosity for each sample Infer how each type of lava would affect the environment Science Content Standards 2.d Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats 7.b Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data 318 Horizons Companies Finding Range 1.d, 1.e Some volcanoes show evidence of past eruptions But, an exact date of the past eruption is unknown The dates of past volcanic eruptions are sometimes given in ranges as shown in the table below The Ϯ (plus or minus) symbol indicates the date is approximate, but is probably a certain number of years before or after the date given MA6: NS 2.0 Example Find the range of years for the last eruption of Medicine Lake Volcano Approximate Date of Last Eruption Golden Trout Creek Inyo Craters Mammoth Mountain Medicine Lake Mono Craters Mount Shasta 5550 B.C Ϯ 1,000 years A.D 1380 Ϯ 50 years A.D 1260 Ϯ 40 years A.D 1080 Ϯ 25 years A.D 1350 Ϯ 20 years A.D 1786 This is what you know: The range of years that Medicine Lake volcano might have last erupted is A.D 1080 ± 25 years This is what you need to find: The latest possible eruption year and the earliest possible eruption year Use these equations: A.D 1080 ϩ 25 ϭ A.D 1105 and A.D 1080 Ϫ 25 ϭ A.D 1055 Answer: The last volcanic eruption occurred some time between the years A.D 1055 and A.D 1105 Practice Problems Find the range in years for the last eruption of Mono Craters Find the range in years for the last eruption of Mammoth Mountain Science nline For more math practice, visit Math Practice at ca6.msscience.com Lesson • Hazards of Volcanic Eruptions 319 seinapmoC snoziroH Use the Internet: The Ring of Fire Materials world tectonic plate map 3-in ϫ 5-in cards colorful yarn push pins computer with internet access Problem As Earth’s lithospheric plates move in relation to one another, magma rises to the surface, and erupts as lava containing gases, solids, and tephra How can scientists predict catastrophic volcanic events and their hazards in an attempt to avoid dangers to humans and wildlife habitats? Form a Hypothesis Make a prediction about how the location of active volcanoes relates to the movements of lithospheric plates to create volcanic eruptions Collect Data and Make Observations Make a data table similar to the one shown below Visit ca6.msscience.com to research the three volcanoes your Science Content Standards 1.d Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where magma reaches the surface 1.e Students know major geologic events, such as earthquakes, volcanic eruptions, and mountain building, result from plate motions 7.a Develop a hypothesis 7.d Communicate the steps and results from an investigation in written reports and oral presentations 320 teacher has assigned to you For each volcano, record the location, type of volcano, and date of most recent eruption in your data table For each volcano, copy this information on one card Plot the location of your volcanoes on a world tectonic plate map using push pins, yarn, and your card Compare your data to the results of your classmates Refer to the location and distribution of the active volcanoes on the world tectonic plate map as you respond to the Analyze and Conclude section of this lab Locations of Active Volcanoes Name of Volcano Location Type of Volcano Date of Most Recent Eruption Analyze and Conclude Identify the location of the three most recent volcanic eruptions Record this information in your data table Infer the movement of the lithospheric plates at the location of the three most recent volcanic eruptions Relate the locations of volcanoes and earthquakes to plate boundaries and their movement Predict the locations and frequency of volcanoes to earthquakes and plate movements Communicate ELA6: W 2.2 3CIENCE Create a Travel Brochure Design a travel brochure for a tour group Include a variety of types of transportation to visit the different volcanic landforms Present your brochure to the class as you inform them of your educational and entertaining volcanic tour Cdgi]6bZg^XVc EaViZ Cdgi]6bZg^XVc EaViZ 8Vg^WWZVc EaViZ 6gVW^Vc EaViZ G^hZ B ^Y CVoXV EaViZ "6i a V G^Y\Z ci^X EVX^[^X EaViZ 8dXdh EaViZ :VhiEVX^[^X ?jVc YZ;jXV EaViZ :jgVh^VcEaViZ Hdji] 6bZg^XVc EaViZ HXdi^VEaViZ E]^a^ee^cZ EaViZ EVX^[^XEaViZ 6[g^XVcEaViZ >cYd"6jhigVa^Vc EaViZ 6ciVgXi^XEaViZ 321 Predicting Volcanic Eruptions As part of the Volcano Disaster Assistance Team based in Menlo Park, California, seismologist Randy White has visited many volcanoes Once alerted by increased earthquake activity in an area, White’s team can arrive at a volcano site within 24 hours, where they interpret seismic data, ground bulging measurements, and atmospheric CO2 and SO2 levels The team’s goal? Predicting if and when a “sleeping volcano” might erupt, and how violent the eruption could be Their recent prediction of eruptions in the Philippines and Latin America saved countless lives Visit Careers at ca6.msscience.com to learn more about the Volcano Disaster Assistance Team Use your research to write a newspaper article describing the work of the Volcano Disaster Assistance Team From Blast to Blast To contain the force of an exploding bomb, engineers are using rock blasted out of a volcano Perlite, a volcanic glass, is part of a material called BlastWrap, which is being built into walls and ceilings, concrete barriers, vehicle protection systems, and even trash cans BlastWrap can dissipate the energy from an exploding bomb the size of a backpack in less than one one-thousandth of a second Visit Technology at ca6.msscience.com to research the properties of BlastWrap Create a brochure or advertisement describing the benefits of this technology 322 U.S Geological Survey/Cascades Volcano Observatory The Year Without a Summer When the Indonesian volcano Tambora erupted in 1815, ash was ejected far into the upper atmosphere Circulating through the atmosphere, the ash reduced sunlight, affecting temperatures worldwide In 1816, northeastern America was particularly hard hit Frosts in May and July killed most crops In June, two large snowstorms caused many deaths In August, ice was seen in lakes and rivers as far south as Pennsylvania Visit History at ca6.msscience.com to learn more about the summer of 1816 Write a poem or song lyrics that describe living in northeastern America during this period Share your work aloud with your class Making the Most of Volcanoes Icelanders use their country’s unique geography astride the Mid-Atlantic Ridge to their advantage While one of Iceland’s 200 volcanoes erupts every few years, these same volcanoes provide geothermal energy power produced by heat from within Earth, such as steam from geysers There’s little land for farming, but residents grow nearly everything they need in greenhouses heated with geothermal energy Eighty-five percent of Iceland’s 300,000 residents use geothermal energy to heat their homes By using geothermal energy rather than imported oil, Iceland’s economy saves an estimated $100 million annually Visit Society at ca6.msscience.com to learn how Iceland uses geothermal resources Locate and quantify specific categories of use Create a bar graph or pie chart illustrating the percentage of each category 323 (t)NASA/Photo Researchers, (b)Palmi Gudmundsson/Getty Images Standards Study Guide CHAPTER /…iÊ Ê`i> Volcanoes are locations where magma reaches Earth’s surface They affect human and wildlife habitats Lesson Volcanoes and Plate Boundaries >ˆ˜Ê`i> Most volcanic activity occurs along plate boundaries where plates move relative to one another • A volcano is a land or underwater feature that forms when magma reaches the surface of Earth 1.d, 1.e, 7.b fissure eruption (p 298) hot spot (p 298) • vent (p 297) • volcano (p 294) • • Buoyant force pushes magma toward Earth’s surface ˆ} >ˆ˜ • Volcanoes occur in areas of high heat flow *ˆVÌÕÀi `i> ˆ} eruptions occur at convergent and divergent plate boundaries • >ˆ˜ Most volcanic • • *ˆVÌÕÀi `i> Some volcanoes form at hot spots not associated with plate boundaries ,i>`ˆ˜} …iVŽ ,i>`ˆ˜} …iVŽ Lesson Volcanic Eruptions and Features >ˆ˜Ê`i> The composition of magma controls volcanic eruptions and determines the different types of lava flow and volcanic features • Chemical composition, dissolved gases, and the temperature of magma are important properties that control volcanic eruptions 1.d, 1.f, 7.g, 7.h cinder cone volcano (p 304) composite volcano (p 304) • shield volcano (p 304) • tephra (p 304) • viscosity (p 302) • • Two types of magma are low-silica, low-viscosity basaltic magma and highsilica, high-viscosity granitic magma ˆ} >ˆ˜ *ˆVÌÕÀivolcanic landforms on Earth’s surface are shield volcanoes, • `i> Three common • cinder cone volcanoes, and composite volcanoes ,i>`ˆ˜} • …iVŽ Volcanoes are forming in the Cascade Range as the Juan de Fuca Plate subducts beneath the North American Plate Lesson Hazards of Volcanic Eruptions >ˆ˜Ê`i> Volcanic eruptions can change human and wildlife habitats • Some volcanic hazards include volcanic ash, lahars, gas emissions, pyroclastic flows, and lava flows Warning signs for an eruption include numerous small earthquakes, changes in gases emitted, and changes in the temperature and movements of the ground surface ˆ} >ˆ˜ • `i> Eruptions*ˆVÌÕÀi are detected using ground-based and space-based methods 2.d, 7.a, 7.b, 7.d lahar (p 314) pyroclastic flow (p 315) • volcanic ash (p 313) • • • ,i>`ˆ˜} …iVŽ 324 Chapter • Standards Study Guide Download quizzes, key terms, and flash cards from ca6.msscience.com Standards Review CHAPTER Linking Vocabulary and Main Ideas Use vocabulary terms from page 324 to complete this concept map Volcanoes are caused by types of volcanoes heat escaping from Earth’s interior through or form layers of basaltic lava form alternating layers of tephra and lava form from can produce volcanic hazards such as lava flows gas emissions Visit ca6.msscience.com for: ▶ ▶ ▶ Vocabulary PuzzleMaker Vocabulary eFlashcards Multilingual Glossary Using Vocabulary Fill in each blank with the correct vocabulary term 10 Lava is ejected from a volcano at the 11 Scientists refer to how easily lava flows as its 12 Volcanoes that not form near plate boundaries are called 13 Pillow lava forms as lava flows from on the seafloor 14 When volcanic debris mixes with water, it can become a fast-moving destroying everything in its path 15 The of basaltic lava is low because the percentage of silica is low Chapter • Standards Review 325 324-327-MSSG6-C7SGA-874183.indd Page 326 4/10/07 3:07:39 PM christ CHAPTER Standards Review Understanding Main Ideas Use the map below to answer questions 5–6 Choose the word or phrase that best answers the question Which of these is a volcanic eruption from an elongated crack in Earth’s surface? A central eruption B fissure eruption C gas eruption 1.d D magma eruption Which type of erupted material is particularly hazardous to aircraft? A ash B dike C lava 2.d D magma The illustration below shows a type of volcano cih gHZVbdj :beZgd What is a central opening from which material is erupted from a volcano? A dike B fissure C lava dome 1.d D vent Cdgi] 6bZg^XV h VcY a h >  Vc 6aZji^ EVX^[^XDXZVc =VlV ^^VcG ^Y\Z  What the Aleutian Islands shown on this map form? A island arc B caldera C dike 1.d D oceanic trench Which type of plate boundary forms a volcanic arc? A continent-to-continent convergent B divergent C ocean-to-ocean convergent 1.e D ocean-to-continent convergent Where does magma form before it moves toward Earth’s surface? A within the slab B at the inner core C in the mantle above the slab 1.d D along the center of the ridge Which type of volcano, shown above, is made entirely of tephra? A shield B caldera C cinder cone 1.d D composite 326 Chapter • Standards Review What is the most common dissolved gas in magma? A carbon dioxide B carbon monoxide C sulfur dioxide D water vapor 1.d Standards Review ca6.msscience.com Standards Review Applying Science Cumulative Review Predict which volcanic hazards you would expect from Mount Shasta if it were to erupt in 2.d your lifetime 10 Explain why scientists would want to monitor glacial ice located near the vent of an erupting 2.d volcano 11 Hypothesize Imagine you are hiking and encounter a dense, dark volcanic rock that is spread out in layers for many kilometers Write a statement about the type of eruption you think formed this rock and the composition of the 1.d magma that supplied it 12 Infer what type of volcano Popocatepetl is, which is located in Mexico at the boundary region between the North American and 1.d Cocos Plates 13 Explain why subduction zones form CHAPTER 1.e 14 Describe the difference between basaltic and 1.d granitic magma 15 Describe the effects pyroclastic flows have on 2.d humans 16 Illustrate how a sill forms How is it different 1.d from a dike? 17 Explain why active volcanoes not occur along 1.f the east coast of the United States 18 Identify the plate tectonic setting that formed 1.e Mount Shasta 19 Defend the following statement: Most volcanoes that occur at the leading edges of continents along the Pacific Ocean are composite volcanoes 1.e 3CIENCE 20 Write an informative pamphlet that lists examples of volcanic hazards associated with volcaELA6: W 1.5 noes in the Cascade Range 21 Explain how seafloor spreading works 1.a 22 Relate the three major types of plate boundaries to main types of stress expected at these 1.e boundaries 23 Describe what happens to the energy of seismic waves as the distance from the focus 1.g increases Applying Math Use the chart below to answer questions 24–26 Volcano Approximate Date of Last Eruption Golden Trout Creek 5550 B.C Ϯ 1,000 years Inyo Craters A.D 1380 Ϯ 50 years Mammoth Mountain A.D 1260 Ϯ 40 years Medicine Lake A.D 1080 Ϯ 25 years Mono Craters A.D 1350 Ϯ 20 years Mount Shasta A.D 1786 24 Find the range in years for the last eruption of Golden Trout Creek MA6: NS 2.0 25 Find the range in years for the last eruption of Medicine Lake MA6: NS 2.0 26 Find the range in years for the last eruption of Mammoth Mountain MA6: NS 2.0 Chapter • Standards Review 327 Standards Assessment CHAPTER Use the table below to answer questions and Plate The diagram below shows Earth’s lithospheric plates Plate Boundaries Number of Number of Convergent Divergent Boundaries Boundaries African Antarctic IndoAustralian Eurasian North American Pacific South American 1 4 2 :JG6H>6CEA6I: CDGI=6B:G>86C EA6I: 6G67>6C EA6I: ?J6C9:;J86 EA6I: 8D8DHEA6I: E68>;>8 EA6I: 6;G>86CEA6I: C6O86 EA6I: HDJI= 6B:G>86C EA6I: >C H8DI>6EA6I: 6CI6G8I>8 EA6I: Determine movement of the Pacific Plate Determine which plate has the most boundaries that are being pulled apart A north-northwest A African B north-northeast 1.e B Antarctic C south-southwest C Indo-Australian D south-southeast D Pacific Predict which plate will be surrounded by the most volcanoes The lava of a particular volcano is high in silica, water vapor and, other gases What kind of eruptive force will likely result? A explosive A Antarctic 1.f 1.d 1.f B quiet flowing B Eurasian C thick bubble-like lava dome C Indo-Australian D flood basaltic D Pacific Volcanoes are not usually associated with Identify the characteristics associated with a shield volcano A A layers of tephra and lava flow B continental divergent 1.d oceanic divergent B tallest volcanoes C ocean-to-continent convergent C large, broad volcanoes D continent-to-continent convergent 1.d D found at convergent continental boundaries 328 Chapter • Standards Assessment Standards Assessment ca6.msscience.com Standards Assessment 10 What causes magma to be forced upward toward Earth’s surface? A The magma has a higher density than the sur1.d rounding rock B Magma that has medium viscosity has high silica 1.d C Magma that has medium viscosity has low silica C Magma has a different composition than the surrounding rock What is the relationship between silica content and viscosity? A Magma that has less silica is more viscous B The magma has a lower density than the surrounding rock D Magma has the same composition as the surrounding rock CHAPTER D Magma that has more silica is more viscous 11 The photo below shows a volcanic eruption What is the relationship between temperature and viscosity? A The higher the temperature, the more viscous 1.d the magma B The lower the temperature, the more viscous the magma C The lower the temperature, the less viscous the magma D Temperature has no affect on viscosity 12 Which feature forms when the top of a volcano collapses into a partially emptied magma chamber? A caldera Infer what volcanic hazard buried cities, town, and field during this eruption A earth flow 2.d 1.d B crater C fissure D sill B lava flow C mud flow D pyroclastic flow What is made of layers of tephra and lava? A lava dome 1.d B cinder cone volcano C composite volcano D shield volcano Chapter • Standards Assessment 329 Kevin West/AP/Wide World Photos ... Horizon Companies LESSON Science Content Standards 1.d Students know that earthquakes are sudden motions along breaks in the crust called faults and that volcanoes and fissures are locations where... distribution of the active volcanoes on the world tectonic plate map as you respond to the Analyze and Conclude section of this lab Locations of Active Volcanoes Name of Volcano Location Type of... table similar to the one shown below Visit ca6.msscience.com to research the three volcanoes your Science Content Standards 1.d Students know that earthquakes are sudden motions along breaks in the