module 1 educator’s guide overview -...

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Volcanoes:Local hazard,global issueModule OverviewMiddle school students are interested involcanic eruptions because of their dramaticnature and because of the sensational destruction they can cause. TheNational Geography Standards expect students to understand howphysical processes like plate tectonics shape and change patterns in thephysical environment, how the characteristics of different environmentsboth encourage and constrain human activities, and how natural hazardsaffect humans. Detecting change and tracking processes in Earth’ssystems is an important component of NASA research. This module allowsstudents, like NASA scientists, to explore two ways that volcanoes affectEarth: by directly threatening people and the environments adjacent tothem, and by ejecting aerosols into the atmosphere. Through threeinvestigations, students explore issues of volcano hazards at differentscales, from their local environment to the global effect of volcanic aero-sols on climate and aircraft safety.

Investigation 1: How close is safe? Buffer zone developmentThis investigation provides an overview of the local effects of volcanism.Students categorize causes, effects, and responses to volcanic hazards.They observe the visible effects of Mount St. Helens’ 1980 eruption overtime. Based on these observations students identify a buffer zone toprevent development in dangerous locations.

Investigation 2: Sensing volcanic effects from spaceThe second investigation provides students with basic understandingabout volcanoes and aerosols as well as skills in remote sensing. Stu-dents learn about volcanic aerosols and how to interpret satellite data.This investigation reinforces skills of comparison as students measure andgraph satellite data to compare various satellite signals.

Investigation 3: Tracking world aerosol hazardsIn this investigation, students are introduced to a global hazard of volcanicaerosols: aircraft damage. In small groups, students use satellite imagesto create time series of global aerosol hazards. By collecting and organiz-ing data, students designate global locations with high aerosol dangers.Two methods of observation are used, and students compare the useful-ness of each strategy.

Geography StandardsThe World in Spatial Terms

• How to use maps and

•

Phy•

Env•

Use•

SciUnif

••

Scie•

Life•

•Ear

•Scie

•

SciePers

•••

Module 1 Educator’s Guide Overview

Standard 1:
other geographic representations,tools, and technologies to acquire,process, and report informationfrom a spatial perspectiveStandard 3: How to analyze thespatial organization of people,places, and environments on
Earth’s surface

sical SystemsStandard 7: The physical pro-cesses that shape the patterns of

Earth’s surface

ironment and SocietyStandard 15: How physical

systems affect human systems

s of GeographyStandard 18: How to applygeography to interpret the presentand plan for the future

ence Standardsying Concepts and ProcessesSystems, order, and organizationConstancy, change, and measure-ment

nce as InquiryAbilities necessary to do scientific

inquiry

ScienceStructure and function in livingsystems

Populations and ecosystems

th and Space ScienceStructure of the Earth system

nce and TechnologyUnderstandings about science and

technology

nce in Personal and SocialpectivesNatural hazardsRisks and benefits

Science and technology in society

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Connection to the CurriculumThis module can be used in geography and science classes to extend astudy of volcanism and to practice skills in map interpretation, remotesensing, and problem solving. In addition, it provides students with real-world contexts in which to learn about ways humans learn to adapt tohazardous physical systems. This module also reinforces mathematicalskills of estimation, graphing, and computation. Students apply many

language arts skills through readings.

TimeInvestigation 1: Two 45-minute sessionsInvestigation 2: Two 45-minute sessionsInvestigation 3: Three 45-minute sessions

Module AssessmentAt the completion of the unit, students may be given the assignment ofpreparing a brief to an international organization in which they must

address this statement:

Roughly 28 percent of Earth’s surface and over half of its popula-tion are directly affected by volcanism. Volcanism has wideeffects on world rainfall, temperature, and other atmosphericconditions. Summarize the potential effects of volcanism on theworld population based on the material studied in this module.Suggest ways humans can prepare for and adapt to this dynamicaspect of Earth’s physical system.

Mathematics StandardsNumber and Operation

• Compute fluently and make

reasonable estimates

Algebra• Understand patterns, relations, and

functions

• Analyze change in various contexts

Measurement• Understand measurable attributes

of objects and the units, systems,and processes of measurement

• Apply appropriate techniques, toolsand formulas to determine mea-

surements

Data Analysis and Probability• Develop and evaluate inferences

and predictions that are based on

data

Problem Solving• Apply and adapt a variety of

appropriate strategies to solveproblems

Communication• Communicate mathematical

thinking coherently and clearly topeers, teachers, and others

Connections• Recognize and apply mathematics

in contexts outside of mathematics

Representation• Create and use representations to

organize, record, and communicatemathematical ideas

• Use representations to model andinterpret physical, social, and

mathematical phenomena

Technological LiteracyStandards

Nature of Technology• Standard 3: Relationships among

technologies and the connectionbetween technology and other

fields

Technology and Society• Standard 4: The cultural, social,

economic, and political effects of

technology

Abilities for a Technological World• Standard 13: Assess the impact of

products and systems

Module 1 Educator’s Guide Overview

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How close is safe?Buffer zonedevelopment

Investigation OverviewThis investigation provides an overview of thelocal effects of volcanism. Students categorizecauses, effects, and responses to volcanic hazards by focusing on theinterdependence of all Earth systems. Using various remotely sensedimages, students observe the visible effects of Mount St. Helens’ 1980eruption over time. Based on these observations students identify a bufferzone to designate safer locations for development.

Time required: Two 45-minute sessions

Materials/ResourcesLog 1, Briefing, and Log 2 (one copy per student)One set of Cause and Effect Statements, cut into strips (per group)Poster paper for categorization (per group)Images needed (one copy per group)

Figure 1: Mount St. Helens, March 1980, before the eruptionFigure 2: Mount St. Helens, June 1980, after the eruptionFigure 3: Aerial photograph of 1980 damage to Mount St. HelensFigure 4: Mount St. Helens in 1999Figure 5: Mount St. Helens hazards map

Blank overhead transparency (one per group)Five different colors of transparency markersRuler (one per group)Masking tape

Content PreviewGeographers conceptualize Earth in terms of physical systems (thelithosphere, the biosphere, the hydrosphere, and the atmosphere) andhuman systems that are unified in a single, highly interconnected system.Changes in one system lead to changes in other systems, with an impacton a variety of scales, from local to regional to global. Volcanoes providean outstanding opportunity to highlight the relationships between humanand physical systems and how humans deal with natural hazards.

Geography Standards

Standard 15: Environmentand Society

How physical systems affecthuman systems

• Analyze ways in which humansystems develop in response toconditions in the physicalenvironment.

• Describe the effect of natural

hazards on human systems.

Standard 7: PhysicalSystems

The physical processes thatshape the patterns of Earth’ssurface

• Predict the consequences of aspecific physical process

operating on Earth’s surface.

Standard 3: The World inSpatial Terms

How to analyze the spatialorganization of people, places,and environments on Earth’ssurface

• Analyze and explain distributions ofphysical and human phenomenawith respect to spatial patterns,

arrangements, and associations.

Geography SkillsSkill Set 4: Analyze GeographicInformation

• Interpret information obtained frommaps, aerial photographs, satellite-produced images, and geographicinformation systems.

• Interpret and synthesize informa-tion obtained from a variety of

sources.

Skill Set 5: Answer GeographicQuestions

• Make generalizations and assess

their validity.

Module 1 Educator’s Guide Investigation 1

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Classroom ProceduresBeginning the Investigation1. Explain that the purpose of the module is to

investigate the effects of volcanoes. Geographersare vitally interested in learning about changescaused by volcanoes at different scales, from thelocal (immediately adjacent to volcanoes) to theglobal (world atmospheric conditions affected byvolcanic eruptions). Give students time to discusswhat they already know about volcanoes and theirlocal-to-global effects.

2. Distribute Log 1 and have students read thebackground and objectives. Distribute the Briefingand have students read the narrative account ofMount St. Helens’ 1980 eruption. You may askstudents to take turns reading this dramatic story ina “reader’s theater.”

3. NASA monitors volcanoes because of their signifi-cant effect on people and the environment. Intro-duce or review the following terms used to describethe environment in Earth-systems terms:• Hydrosphere: Earth system dealing with water

(hydro-), including surface water systems (lakes,rivers, oceans) and frozen water (glaciers, polarice caps) as well as water beneath the surfaceof Earth (aquifers, groundwater, etc.)

• Lithosphere: Earth system dealing with land(soil, rocks, etc.)

• Atmosphere: Earth system dealing with air• Biosphere: Earth system dealing with plant and

animal life (flora and fauna)

Have students record definitions in the Log.

4. Divide the class into groups of 3-5 and distributethe Cause and Effect Statements, cut into strips,one set per group.

• Review the statements with students to makesure they understand the vocabulary.

• Ask students to organize the strips into threegroups: Causes, Effects, and Human Re-sponses. Some statements may require a finedistinction between “cause” and “effect”; developworking definitions as a class if necessary.(Suggested definitions: Cause—incidents thatlead up to or are related to the actual eruptionevent. Effect—incidents that result from theactual eruption event).

• Students complete item 3 in the Log.

5. Using large sheets of poster paper and tape, havestudents classify the statements again, this timeinto more specific categories shown in Log 2:Cause and effect organizer. Be sure that allstudents understand the categories. Discuss thetypes of cues they would use to determine astatement’s classification. For example, studentsshould identify that statements dealing with theplant and animal life of the area would be placedunder “Effects on the Biosphere.”

• Students record their categorizations on Log 2.

6. Ask selected groups to share their classificationswith the class. If groups disagree about astatement’s classification, allow them to explaintheir underlying thought process. Use points ofdisagreement to reinforce the concept that Earthsystems function interdependently, so it is some-times difficult to determine which “-sphere” is beingaffected.

7. Debrief this activity by highlighting that effects andconsequences such as the ones listed requireconsiderable lengths of recovery time after aneruption. How people prepare for and respond tovolcanic eruptions is vital to the safety and produc-tivity of an area. Explain that NASA images showthe extent of damage after an eruption and providedata useful to lessen the human impacts of pos-sible future eruptions.

Developing the Investigation8. Distribute Figure 1: Mount St. Helens, March

1980, before the eruption to each group. Explainthat this is a false color Landsat image, whichmeans that the colors on the image are not thesame as would appear to the human eye. In thisimage, vegetation is red.


Causes

Structure ofthe Volcano

The EruptionEvent

Effects

Effects on...Lithosphere

Hydrosphere

Biosphere

Atmosphere

Human Activities

Human Responses

Clean-Up Efforts

Responses toEnvironmentalHazards

Monitoring Efforts

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9. Guide students in interpreting the image using thefollowing questions:• What would you look for to identify a river?

(Look for meanders or curves in a line.)• How would you identify the location of the

volcano’s peak? (Look for dark gray or blackareas surrounded by little vegetation. Theserepresent snow and glaciers that are on top ofthe volcano.)

• How would you find areas of vegetation? (Lookfor red areas since this is a false color imageand living vegetation is reddish.)

• Why might some areas of vegetation havestraight boundaries? (They are probably bound-aries for agricultural land or some other man-aged landscape.)

Have students complete item 4 in the Log.

10. Ask students to review the Cause and EffectStatements they organized earlier in the investiga-tion. Have them record in their log three things thatthey would expect to be able to observe in a falsecolor image taken after an eruption. Allow studentsto discuss their predictions with the class. Theyshould mention things like:• less red color because much of the vegetation

was killed by the blast• changes in the course of rivers or the develop-

ment of new lakes as debris obstructed the flowof rivers

• changes in the shape of the volcano due tolandslides

11. Distribute a blank overhead transparency andtransparency marker to each group. Instructstudents to mark the corners of Figure 1 on thetransparency to aid in lining up other images later.

12. Ask students to locate the summit of the volcano(in the lower left area of the image) and then tracethe extent of the volcano. Students should create akey at the bottom of the transparency for eachcolor used throughout the investigation.

13. Explain the concept of a buffer. A buffer providesan area to absorb negative consequences ofphysical or human activities. For example, treebuffers can serve to protect a neighborhood fromhighway traffic and noise, while an uninhabitedbuffer area can protect people from some dangersof natural hazards.

In a different colored transparency marker, askstudents to sketch the area they think should bethe buffer zone for safety around Mount St. Helens.

14. Distribute Figure 2: Mount St. Helens, June1980, after the eruption.• Instruct students to compare this figure to

Figure 1.• Have students discuss their reactions to the

changes from Figure 1 to Figure 2. In whatways was the environment disturbed anddisrupted by the eruption? In what ways wasvegetation altered? The flow of rivers? Studentsshould check to see the changes they predicted.Were their predictions accurate?

• Have students measure the areal extent of thedamage in four directions using a ruler and thescale of the image.

• Have students place the transparency on Figure2, lining up the corner marks.

• In another color, have students trace the bound-ary of the extent of the disruption and devasta-tion brought on by the eruption. Ask howeffective their buffer would have been for thisparticular eruption.

15. Have students review the Cause and Effect State-ments again to imagine what the area in this imagewould look like at ground level. Then, displayFigure 3: Aerial photograph of 1980 damage toMount St. Helens to illustrate what the land lookedlike after the eruption.

16. Ask students to formulate a hypothesis about thepresent environment around Mount St. Helens. Whatwould it look like today? Using a new color transpar-ency marker, have students draw in with dashed lineshow much of the area they think probably still showseffects of the 1980 eruption today.

17. Distribute Figure 4: Mount St. Helens in Decem-ber 1999. Students need to line this image up withthe lower right corner of their transparency. Ex-plain that instead of vegetation appearing red, in atrue color image vegetation looks green like it doesin the real world. Ask students to compare thisimage with the previous two. How has the localenvironment changed? Ensure that students noticethe vegetation regrowth in some areas. Where hasregrowth occurred, and where has it not? Havestudents look for patterns and explanations for theareas of regrowth. (Explanations could include: Theimpact was more severe and lasting in the directionof the blast. The area directly adjacent to thevolcano was slowest to grow vegetation. Areasalong the river and surrounding Spirit Lake havebegun to recover vegetation.)


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18. Using a different color marker, ask students to drawa second safe buffer zone around the volcanoapplying this new information. Students shouldrecord their justification for the boundary by statingwhich effects are being addressed by their newbuffer zone.

Concluding the Investigation19. Compare the second buffer zone to the buffer they

drew originally. Ask how many groups made theirsecond buffer zone bigger.

Students may assume that the next eruption willaffect the same area, which would not necessarilybe the case. Ask what other information studentsor scientists would need to create a buffer zonethat took this possibility into account.

20. Remind students that scientists are constantlymonitoring changes with volcanoes, hoping thatnew information will help the area be safer andmore prepared for potential eruptions. Using datafrom several different years allows people to makewiser decisions. If students changed their bufferzone, they understand the need to respond toadditional information about dangers.

21. Circulate Figure 5: Mount St. Helens hazardsmap for students to compare their second bufferzone area with the hazard areas identified by theU.S. Geological Survey.

22. Ask students to review the Cause and EffectStatements they used in the beginning of theinvestigation. Have them identify which effectsmay have been less of a problem if there had beena sufficient buffer zone in place before the 1980eruption of Mount St. Helens. Have studentsrecord their answers in their Log. Provide time forwhole group discussion of the possible effects andlimitations of buffer zones.

BackgroundVolcanoes are dangerous, but they are also veryimportant to humans. Volcanic eruptions contributesubstantially to soil fertility. In the Andes, many peoplelive on the flanks or at the foot of active compositevolcanoes, largely because of the fertility of the volca-nic deposits. The same is true in the Philippines whereresidents near active volcanoes like Mount Mayon andMount Taal regularly move away during eruptions, onlyto move right back when the danger subsides. Thesetwo cases present good examples of how people learnto live and adapt to hazardous environments.

Mount St. Helens is one of many composite (strato-volcano) volcanoes in the Cascade Range of theNorthwest United States. Mount St. Helens has beenone of the most active volcanoes in the Pacific North-west although before the eruption in May 1980, it hadbeen dormant since 1857.


Cinder Cones

Made primarily from explosiveeruptions of lava. Blown intothe air, the erupting lavabreaks apart into the smallfragments known as cinders.The fallen cinders accumulateinto a cone around thevolcano’s central vent (the“hole in the ground” from whichthe lava emerged).

Not associated with anyparticular tectonic activity.Some are found near currenttectonic boundaries, andothers are near old boundaries.

Sunset Crater (Arizona),Capulin Mountain (New Mexico)

Formation/Location

Location

Examples

Shield

Massive fluid lavaflows and slowlybuilds up a gentlysloping volcanicshape.

Primarily locatedalong tectonicspreading centersor at “hot spots.”

Kilauea, MaunaLoa (Hawaii)

Composite/Stratovolcanoes

Built from both explosiveeruptions and quietereruptions. Layers of tephra(ash, cinders, and othermaterial blown into the air)alternate with layers of lavato create steep-sided, oftensymmetrical cones.

Stratovolcanoes arelocated primarily alongtectonic subduction zones,where two plates slowlycollide.

Mount Fuji (Japan),Mount St. Helens(Washington)

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More detailed information about the Cascade Range,Mount St. Helens, and the 1980 eruption can be foundat the USGS/Cascade Volcano Observatory web site:<http://vulcan.wr.usgs.gov/Volcanoes/MSH/framework.html>

EvaluationStatement CategorizationFollowing are suggested categorizations and justifica-tions. Some statements are listed in more than onecategory to illustrate the multiple categorizations thatmay occur.CausesStructure of the Volcano

15. Composite volcanoes erupt explosively. (State-ment describes Mount St. Helens’ volcano type.)

16. Composite volcanoes are made of alternatinglayers of lava, ash, and other volcanic debris.(This layering of debris from former eruptionsgives the volcano its structure as well asproviding considerable material to spew duringan eruption.)

18. Magma contains high concentrations of gasthat may cause an explosion that breaksmagma into pumice and tiny ash particles.(This statement describes magma behavior ina composite volcano.)

The Eruption Event2. The mountain “awoke” with a series of steam

explosions and bursts of ash. (This was a causeleading to the effect of an enormous ash cloudthat traveled the globe [10, 14] and the develop-ment of global ash monitoring stations [9].)

3. The mountain shook from a strong, magnitude4.2 earthquake. (This statement is associatedwith activity immediately preceding the eruption.)

4. The entire face of the mountain broke freeand slid downward in a giant rock avalanche.(Depending on the interpretation, this state-ment could apply to the conditions surround-ing the eruption or an effect of the eruptionon the lithosphere. Students could justifyplacement in either of these categoriesbased on their distinction between a physicalcause and effect.)

5. The lava contained dissolved water thatexploded into superheated steam. (This wasa cause leading to the effect of an enormousash cloud that traveled the globe [10, 14] andthe development of global ash monitoringstations [9].)

19. Within hours of the blast, mixtures of gas,pumice, and ash swept down the north side ofthe volcano at speeds up to 160 kilometers/hour (100 miles per hour) and at temperaturesof over 648˚ C (1200˚ F). (While this mentionsa timeline of “within hours of the blast,” thespeed and temperature of the materials causedmany of the devastating effects listed.)

EffectsLithosphere

1. Volcanic deposits literally reshaped the entireregion around the mountain. (The termdeposits is key in this statement to suggestactions after the actual eruption.)

13. Enormous mudflows gushed down the moun-tain. (Mudflows are made up of primarilymaterials from the lithosphere, but studentsmay see this as an interaction between thelithosphere and the hydrosphere.)

20. A fan-shaped pumice plain developed to thenorth and directly in front of the crater. (Thedeposition of the pumice reshaped the physicallandscape in front of the crater.)

21. Layers of pyroclastic flow (pumice, ash, andgas) were deposited as thick as 20 meters(60 feet) deep along the north side of thevolcano. (Volcanic deposits, again, affectingthe landscape.)

Hydrosphere22. The Columbia River was closed to freighter

traffic for several days to remove debris. (Thereference to freighter [shipping] traffic makesthis statement fit better within effects on humanactivities than effects on the hydrosphere, butstudents may initially associate the river withthe hydrosphere.)

28. A debris avalanche blocked the natural outletof Spirit Lake. (The natural circulation pro-cesses of Spirit Lake were affected.)

29. Several new lakes were formed by debrisdeposits, but these natural dams were unstableand could fail and flood the streams. (Studentsshould recognize that actions such as naturalor artificial damming have consequences suchas potential failures, which ultimately can addconsiderable stress to the rest of the riversystem.)

Biosphere7. Thousands of deer, elk, bear, and other

animals died. (Fauna are all part of the bio-sphere.)

8. Almost 594 square kilometers of forest weredestroyed. (Flora are part of the biosphere.)


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17. Plant growth was severely slowed for yearsafter the eruption. (The soil must have time torecover for the plant life to return. At first,though, only very short hardy plants will beable to survive.)

23. Trees were stripped from the hillsides as far as10 kilometers from the volcano. (The blastliterally tore many trees out of the ground.)

24. Around the edges of the blowdown zone, treeswere killed simply by the intense heat of theblast. These trees are called Standing Dead.(Beyond the area where trees were torn out ofthe ground, trees were singed and killed. TheStanding Dead resembled deciduous treesduring the winter, except that they were not justdormant.)

Atmosphere10. Tiny ash particles were thrust 24 kilometers

into the sky and continued for about ninehours. (Material was being added to theatmosphere.)

14. Small ash particles reached the eastern UnitedStates within three days of the blast and circledthe globe within two weeks. (This statementillustrates the global extent of the atmosphericimpact. Material from an eruption in the UnitedStates traveled around the globe in less thantwo weeks.)

Human Activities6. Shipping channels were blocked. (Students

may place this statement in either the hydro-sphere or in human activities. This statementspeaks more directly to the human activities onthe river rather than effects on the hydrology ofthe area, so it is better categorized here.)

11. Many communities and agricultural areas wereaffected by falling ash. Machinery and cropswere damaged. (The emphasis on agricultureand technology focuses this statement on theeffects on human activities.)

12. A small airplane narrowly avoided disasterwhen the pilot put the plane into a steep dive togain speed and turned south, away from theash cloud. (This statement refers to humanactivities in the atmosphere but is bettercategorized as an effect on human activities.)

22. The Columbia River was closed to freightertraffic for several days to remove debris. (Thereference to freighter, shipping traffic makesthis statement fit better within human activitiesthan effects on the hydrosphere.)

Human ResponsesClean-Up Efforts

25. From May to September 1980, the U.S. ArmyCorps of Engineers removed 32 million cubicmeters of debris from the Cowling River. (TheCorps was working to free up shipping chan-nels again.)

Environmental Hazards26. Levees and retaining structures were built to

control sediment and debris deposits. Thisprevents deposits from clogging the rivers andhindering boat traffic or causing floodingdownstream. (While levees are designed tocontrol floods and manage water resources, itis important for students to remember thatthese structures sometimes fail just as naturaldams sometimes do [29]. Settling outside thefloodplain is the safest way to minimize flooddamage.)

27. Flood gates were installed to prevent potentialflooding of Spirit Lake caused by future volca-nic activity. (Efforts by humans to controlnatural environmental hazards.)

30. A fish transport system was built to help fishget around the sediment-retention structure.This provided safe passage for salmon andsteelhead returning from the sea. (This systemwas an attempt to reconnect the migration pathof fish that had been disrupted by human-builtstructures. Students should realize that humanactions also have effects on the interactions ofall the spheres, which should be minimized asmuch as possible.)

Monitoring Efforts9. A global network of Volcanic Ash Advisory

Centers was created to observe volcaniceruptions in order to improve aircraft safety.(The VAAC system was created to address theeffects of worldwide volcanic ash hazards.)

31. Scientists carefully watch the activity of magmaunder Mount St. Helens. Nonetheless, heatfrom the magma has led to avalanches (melt-ing snow) and explosions of steam (heatedwater) without warning. (Scientists monitor forchanges that often lead up to volcanic erup-tions to attempt to give some warning beforethe next one.)

32. The U.S. Geological Survey and University ofWashington are watching for volcanic activity ofMount St. Helens. Information on lahar (mudslides) and flood hazards is now collected by


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the USGS and the National Weather Servicewho then issue warnings. (This statementreflects the interagency concern with monitor-ing volcanic activity).

Suggested Key for Log 12. Hydrosphere: Earth system dealing with water

Lithosphere: Earth system dealing with landAtmosphere: Earth system dealing with airBiosphere: Earth system dealing with plants and

animals, flora and fauna5. Responses will vary but might include: loss of

vegetation, changes in shape of the volcano,changes in the course of the river, formation ofadditional lakes.

8. Observations will vary.10. Student estimates will vary but should include

reference to changes in the shape of the volcano,lack of trees, debris flow.

12. Students should observe that Figure 4 is true color;thus vegetation is green in this image rather thanred.

13. Vegetation regrowth can be seen primarily to thenorthwest of the volcano. Directly north of thevolcano is still gray because the area has not yetrecovered.

14. Reasons may vary but should be evaluated forsoundness of the reasoning. A sample answer:The area closest to the blast side of the volcanowas most severely disrupted by the eruption asshown by loss of vegetation and other items, so itis taking the longest time to recover.

15. Student justifications will vary, but the responseshould include why they chose to make the newbuffer zone larger or smaller than the previous one.Answers should also include consideration for theareas of regrowth. For example, areas that aregreen now were not “safe” during 1980, so estab-lishing a buffer based only on Figures 1 or 4 wouldbe misleading.

16. Student responses should illustrate reasoning andcareful evaluation of the significant issues.

17. The paragraph should address both the importance


Related NASA Resourceshttp://volcano2.pgd.hawaii.edu/eos/ Earth Observation System

Volcanology Homepage, provides comparativeinformation on a variety of volcanoes under study.Includes eruption data as well as satellite and aerial

images of each.

Related Resourceshttp://vulcan.wr.usgs.gov/Volcanoes/MSH/framework.html Links

to information about Mount St. Helens. Includesdetails of the 1980 eruption, maps and graphics of theCascades Volcanoes, monitoring efforts, and more.

http://vulcan.wr.usgs.gov/Volcanoes/MSH/May18/summary_may18_eruption.html Summary of the 1980eruption event, including measurements and extent ofdamage

http://volcano.und.nodak.edu/vwdocs/msh/msh.html MountSaint Helens Homepage

http://edcwww.cr.usgs.gov/earthshots/slow/MtStHelens/MtStHelens Landsat progression of images withadditional pictures of selected sites

http://volcano.und.nodak.edu/vwdocs/volc_images/img_st_helens_bw.html Dramatic black and whitepicture of eruption and ash cloud

http://www.avo.alaska.edu/avo3/atlas/atlindex.htm AlaskanVolcano Observatory, outstanding images and textabout all volcanoes in Alaska, the Aleutian Islands,and Kamchatka Peninsula. Regional and local maps.Images of volcanoes, their eruptions, and the effectson the nearby human populations

http://volcano.und.nodak.edu/vwdocs/volc_images/volc_images.html Volcano World page with search-able world map. Students can search for volcanoesby region, country, name, etc. Provides usefulinformation and images from a variety of sources.

and limitations of buffer zones. On one hand,buffers protect humans and human activities fromdirect hazards. However, there are numerouseffects of volcanic eruptions that a buffer cannotaddress such as effects on the various -spheres.By its nature, a buffer zone addresses naturalhazards from a human perspective alone, althoughhumans are not the only living things affected bynatural hazards. This paragraph can also beevaluated for grammar and composition.

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Module 1, Investigation 1:Cause and effect statements

1. Volcanic deposits literally reshaped the entire region around the mountain.

2. The mountain “awoke” with a series of steam explosions and bursts ofash.

3. The mountain shook from a strong, magnitude 4.2 earthquake.

4. The entire face of the mountain broke free and slid downward in a giantrock avalanche.

5. The lava contained dissolved water that exploded into superheated steam.

6. Shipping channels were blocked.

7. Thousands of deer, elk, bear, and other animals died.

8. Almost 594 square kilometers of forest were destroyed.

9. A global network of Volcanic Ash Advisory Centers was created to observevolcanic eruptions in order to improve aircraft safety.

10. Tiny ash particles were thrust 24 kilometers into the sky and were airbornefor about nine hours.

11. Many communities and agricultural areas were affected by falling ash.Machinery and crops were damaged.

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12. A small airplane narrowly avoided disaster when the pilot put the planeinto a steep dive to gain speed and turned south, away from the cloud.

13. Enormous mudflows gushed down the mountain.

14. Small ash particles reached the eastern United States within three daysof the blast and circled the globe within two weeks.

15. Composite volcanoes erupt explosively.

16. Composite volcanoes are made of alternating layers of lava, ash, andother volcanic debris.

17. Plant growth was severely slowed for years after the eruption.

18. Magma contains high concentrations of gas that may cause anexplosion that breaks magma into pumice and tiny ash particles.

19. Within hours of the blast, mixtures of gas, pumice, and ash swept downthe north side of the volcano at speeds up to 160 kilometers per hour(100 miles per hour) and at temperatures over 648˚ C (1200˚ F).

20. A fan-shaped pumice plain developed to the north and directly in frontof the crater.

21. Layers of pyroclastic flow (pumice, ash, and gas) were deposited asthick as 20 meters deep along the north side of the volcano.

22. The Columbia River was closed to freighter traffic for several days toremove debris.

23. Trees were stripped from hillsides as far as 10 kilometers from thevolcano.


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24. Around the edges of the blowdown zone, trees were killed simply by theintense heat of the blast. These trees are called Standing Dead.

25. From May to September 1980, the U.S. Army Corps of Engineers re-moved 32 million cubic meters of debris from the Cowling River.

26. Levees and retaining structures were built to control sediment and de-bris deposits. This prevents deposits from clogging the rivers and hin-dering boat traffic or causing flooding downstream.

27. Flood gates were installed to prevent potential flooding of Spirit Lakecaused by future volcanic activity.

28. A debris avalanche blocked the natural outlet of Spirit Lake.

29. Several new lakes were formed by debris deposits, but these naturaldams were unstable and could fail and flood the streams.

30. A fish transport system was built to help fish get around the sediment-retention structure. This provided safe passage for salmon andsteelhead returning from the sea.

31. Scientists carefully watch the activity of magma under Mount St.Helens. Nonetheless, heat from the magma has led to avalanches(melting snow) and explosions of steam (heated water) withoutwarning.

32. The U.S. Geological Survey and University of Washington are watchingfor volcanic activity of Mount St. Helens. Information on lahar (mudslides) and flood hazards is now collected by the USGS and the Na-tional Weather Service who then issues warnings.


13

BackgroundVolcanoes are like good news, bad news jokes. The good news is that they offer humans benefits

such as rich soil. The bad news is that they are very destructive when they erupt. Because of this contra-diction between productivity and destruction, areas around volcanoes need to be evaluated for safety.Creating a safety zone around a volcano helps to minimize a volcano’s effect on humans. Creating asafety or buffer zone, however, requires information about the extent of previous eruptions compared tohuman settlement patterns. In this investigation you use data at different scales to study the impact ofvolcanic eruptions on the environment and its inhabitants in order to establish a buffer zone.

Objectives: In this investigation, you

• categorize the causes and effects of volcanic eruptions and human responses to them,• measure the extent of damage of the Mount St. Helens 1980 eruption, and• analyze images of a volcano to suggest a settlement buffer zone.

Procedures for the Investigation:1. Read the account of the Mount St. Helens 1980 eruption.2. Define the following elements of Earth’s physical systems:

hydrosphere:

lithosphere:

atmosphere:

biosphere:

3. Categorizing causes, effects, and responsesOrganize the Cause and Effect Statements into three categories. List the strip numbersunder each category title.

Divide the strips into more specific categories using the headings on Log 2: Cause and effectorganizer. Be prepared to explain your choices.

Module 1, Investigation 1: Log 1How close is safe? Buffer zone development

1

Causes Effects Human Responses

14

4. Look at Figure 1. This is a false color image, which means the features in the figure do not have thesame color as they do in real life. The volcano is in the lower left corner. In this image, the vegetation(plant life) appears reddish and the water appears dark blue or black. Locate the following.

Mount St. Helens volcanoSpirit LakeA riverAreas of vegetation

5. Go back to the Cause and Effect Statements that you organized earlier in this investigation. Writedown three changes that you expect to observe in an image taken after an eruption.

6. Place a transparency over Figure 1. Mark the corners of the image onto the transparency to line upthe other images. With a transparency marker, outline the base of the volcano’s cone. Create a keyat the bottom of your transparency. Label the first colored line as Volcano on the key.

7. With a different color transparency pen, draw a line representing the nearest point to the volcanowhere you think people could safely build houses and businesses. This creates a buffer zone.

8. Look at Figure 2, another false color image of Mount St. Helens. This was taken after the 1980eruption. Compare Figure 1 and Figure 2. Write down three changes that occurred.

9. With another color transparency pen, trace the extent of the disruption caused by Mount St. Helens’1980 eruption. Add this color to the key and label it Damage.

10. Think back to the Cause and Effect Statements. What would the area shown in this image look likefrom the ground?

11. Do you think the area has recovered to the way it was before the eruption in 1980? What is the extent

of damage today? Sketch your predicted area on the transparency using dashed lines. Add the

dashed line to your key and label it Estimate for Today.

2


1)

2)

3)

1)

2)

3)

15

12. How is Figure 4 different from Figures 1 and 2?

13. Where has the vegetation around the volcano begun to grow back? Where has it not?

14. Write one reason why some of the areas have recovered from the 1980 blast while other areas stillhave not.

15. With a different color transparency pen, draw a second buffer zone line based on all three images.Should the area be larger than your last prediction? How should you deal with the areas of regrowthand recovery? Record this color on your key and label it Buffer 2.

16. Review the Cause and Effect Statements from the beginning of the investigation. Which of thesestatements would be different if an effective buffer zone was in place before the 1980 eruption?

3


164

17. Write a paragraph discussing both the importance and limitations that buffer zones have whendealing with Earth’s systems.

Referenceshttp://vulcan.wr.usgs.gov/Volcanoes/MSH/framework.html Use this website for more information

about Mount St. Helens and other volcanoes in the Cascades Rangehttp://volcano.und.nodak.edu/vwdocs/volc_images/volc_images.html Use this website to locate

additional volcanoes to research


17

A Slumbering Volcanic GiantMount St. Helens was once one of the most

beautiful mountains in the entire Cascade Range ofthe American Northwest. In 1805, William Clark inthe Lewis and Clark expedition described Mount St.Helens as “perhaps the greatest pinnacle inAmerica.”

The serenity of the mountain and its surround-ings was misleading. One of the Indian names forMount St. Helens was “fire mountain.” LocalIndians were reluctant to approach the mountaindespite the abundant game in the area.

To the experienced observer, the cone shapeand composition of rocks on the mountain boldlyproclaimed Mount St. Helens’ true nature—it was avolcano. Lava flows and multiple layers of ash(powdered volcanic rock) lay everywhere under thecarpet of trees—abundant evidence of many prioreruptions. Volcanic deposits had reshaped theregion around the mountain. Even beautiful SpiritLake was a volcanic accident created by a giantmudflow that rolled down the mountain 3,000 yearsago and backed up a stream.

Mount St. Helens was active between 1832and 1857 during the early settlement of the area byEasterners. But the eruptions were small, and themountain then “dozed off” for the next century.Small settlements became towns, and townsbecame cities like Portland and Seattle. Thesenew neighbors of Mount St. Helens knew themountain only as a sleeping giant. Its violent pastwas largely ignored.

The AwakeningThe quiet ended abruptly in March 1980, with a

series of steam explosions and bursts of ash. Thefollowing story of the eruption of Mount St. Helensillustrates the potential dangers of an eruption fromMount Ranier—a volcano about 120 kilometerssouthwest of Seattle, Washington.

During the months following the initial outbursts,vulcanologists and seismologists watched themountain closely. Small earthquakes accompaniedthe bursts and indicated the movement of fresh lavainto the heart of the mountain. Enormous cracksappeared in the summit and sides of the mountain,

and the entire northern face expanded outwardsome 137 meters. Locals perceived this initialactivity as minor, so in spite of warnings and thedesignation of the mountain and its surroundings asa dangerous “Red Zone,” tourists flocked to the areato get a close view of the fireworks. Residents werestrongly advised to move away, but some refused togo. Likewise, logging companies working in thearea refused to shut down, claiming to “know themountain.” Vulcanologists established severalcamps around the mountain to monitor its activity.Some of the camps had to be dangerously close tothe mountain to provide the necessary data. Thescientists who manned the camps in shifts knewthey were at risk.

The Main EruptionOn May 18, a quiet Sunday morning, a few

observers were at their stations, watching MountSt. Helens. Tourists and loggers were also nearby.At 8:32 a.m. a small aircraft with two geologistsaboard flew directly over the central cone.

Eleven seconds later, a strong earthquakeshook Mount St. Helens. The whole north face ofthe mountain broke free and slid downward as agiant rock avalanche. In seconds, pressure in themass of hot lava inside the mountain dropped;water that had been dissolved in the lava turnedinto superheated steam, fragmenting the lava into afine powder ash. This mass of superheated steamand ash blasted upward and outward over the topof the avalanche, roaring to the north and west atspeeds reaching hundreds of miles an hour. Thepilot of the small aircraft narrowly avoided disasterby putting the “plane into a steep dive to gainspeed” and turning sharply south, away from theexpanding ash cloud.

Every living thing within about 16 kilometers ofthe volcano on the north side—tree or bush, humanor animal, scientist or layman—was destroyed.Some of the people took a few quick pictures.Then, realizing their situation, most ran or tried todrive away from the approaching cloud of dust andsteam. The near-supersonic blast of rock, ash, andhot gas engulfed the area with enough force touproot trees. The temperature within the cloudreached 260°C (500°F), more than enough to startfires or burn exposed skin. The rock avalanche

5

Module 1, Investigation 1: BriefingNarrative of Mount St. Helens 1980 eruption

18

roared over Spirit Lake and the valley of the NorthFork of the Toutle River, burying them under layersof rock up to several hundred feet thick.

Moments after the rush of the avalanche andash cloud, enormous mudflows—formed whenglacial ice and snow that had capped the mountainwere melted by the intense heat—surged down themountain. Masses of mud poured down the nearbyriver valleys, sweeping away buildings, vehicles,trees, and bridges. One flow even blocked theshipping channel of the Columbia River, 88 kilome-ters downstream.

Millions of tons of fine ash were thrown highinto the air and carried hundreds and thousands ofmiles downwind. These clouds, visible in satelliteimages, dropped several inches of ash over manycommunities and agricultural areas, ruining ma-chines and crops.

The TollTo the nation, and especially to those living

nearby, the May 18 eruption was apocalyptic. Thecrown and heart of a whole mountain had beenblasted away, and the surrounding countrysidedevastated. The energy released by the eruptionwas estimated at 10 megatons, an explosionthousands of times stronger than an atomic bomb.

• Thousands of deer, elk, bear, and smalleranimals perished—in addition to 57 humans.

• Over 593 square kilometers of forest weredestroyed, including three billion board feetof timber estimated at $400 million in value.

• Numerous buildings, bridges, roads, andmachines were destroyed, and farms andcommunities up to 1,600 kilometers awaywere partially buried in ash.

• One hundred sixty-nine lakes and more than4,800 kilometers of streams had either beenmarginally damaged or destroyed.

• Losses to property and crops were set atmore than $1.8 billion.

Yet, the impact on human life could have beenmuch greater if the main eruption had occurred ona workday or if the blast had been directed south-west toward the Portland/Vancouver metropolitanarea (just 72 kilometers away) or if the wind hadbeen blowing toward the southwest.

As large and destructive as the May 18 erup-tion appeared, it was a relatively small eruptionwhen seen in context. Thick deposits of oldervolcanic rock around Mount St. Helens attest tomuch larger eruptions in its past. Mount St. Helensis also only one of many volcanoes that dot theCascade Range. All of these volcanoes grew inthe same geologic setting. Some eruptions atother Cascade volcanoes have been truly huge,such as the explosion nearly 7,000 years ago—100 times larger than the May 18 eruption—thatreduced Mount Mazama to Crater Lake. Eruptionsranging in size from the May 18 eruption to theMazama blast could occur at any time at any of theCascade volcanoes. For the metropolitan centersof Portland, Seattle-Tacoma, and San Franciscothat have grown up among the Cascade volcanoes,this is a serious concern.

Source: NASA’s Classroom of the Future. http://www.cotf.edu/

ete/modules/volcanoes/vnarrative1.html

For an extended discussion of Mount St. Helens, see

http://vulcan.wr.usgs.gov/ljt_slideset.html

Module 1, Investigation 1: BriefingNarrative of Mount St. Helens 1980 eruption

6

19

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white = snow and glaciersgrey = areas destroyed by 1980 debris flow which have not recovered

Orientation: NNESource: http://volcano.und.nodak.edu/vwdocs/volc_images/img_st_helens.html

11

Module 1, Investigation 1: Figure 4Mount St. Helens in December 1999

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