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NISAR:TheNASA-ISROSARMission

MonitoringVolcanicActivitywithRadarMany volcanic eruptions are preceded by surfacedeformation induced by moving magma beneath theground. Measuring this deformation is key tounderstanding the potential for future eruptions. Radar

observationsfromNISARandothersatellitemissionscanplay a direct role in helping to monitor volcanoes andassessassociatedhazards,bothduringperiodsofunrestandduringensuingeruptions.

MonitoringVolcanicHazards

Earth is home to about 1,500 volcanoes that have erupted in the past 10,000years, and today volcanic activity affects the lives and livelihoods of a rapidlygrowingnumberofpeoplearoundtheglobe.Volcaniceruptionsdestroycitiesandtowns,ejectashcloudsthatdisruptairtravel,andimpactregionalagriculture.

Volcanic hazards can be local, regional or globalVolcanic eruptions produce a large range of associated hazards.Explosiveeruptionsejectballisticrockfragmentsthatcanimpactthesurface up to several kilometers away from the vent. Smallerfragmentsarecarriedupwardineruptioncolumnsthatsometimesreachthestratosphere,formingeruptioncloudsthatposeaserioushazardtoaircraft.Volcanicashfallcancollapsebuildings,andevenminoramountscanimpactelectricalsystemsanddisrupteverydaylife.Volcanicgasescontributetohealthproblems,andalsotoacidrainthatcausescorrosionandharmsvegetationandlivestock.Lavaflows inundate property and destroy infrastructure. Volcanicmudflowshavethepotentialtodevastateentirecitiesevenfarfromthesourcevolcano.Pyroclasticflows—high-speedavalanchesofhotpumice,ash,rockfragments,andgas—canmoveatspeedsinexcessof100km/hranddestroyeverythingintheirpath.ImageCredit:USGS

TheNISARMission:DiagnosingthestateofEarth’slandThe NASA–ISRO Synthetic Aperture Radar (NISAR) mission, a collaborationbetweentheNationalAeronauticsandSpaceAdministration(NASA)andtheIndianSpaceResearchOrganization(ISRO),willprovideall-weather,day/nightimagingofnearlytheentirelandandicemassesoftheEarthrepeated4-6timespermonth.NISAR’sorbitingradarswillimageatresolutionsof5-10meterstoidentifyandtracksubtlemovementoftheEarth’slandanditsseaice,andevenprovideinformationaboutwhatishappeningbelowthesurface.Itsrepeatedsetofhighresolutionimagescaninformresourcemanagementandbeusedtodetect small-scale changes before they are visible to the eye. Products areexpected to be available 1-2 days after observation, and within hours inresponsetodisasters,providingactionable,timelydataformanyapplications.

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Data fromNISAR and other radarmissions allow us toidentify and monitor surface deformation at quiescentand active volcanoes through the use of radarinterferometry(InSAR).OnlyInSARhasthecapabilityformonitoring deformation at virtually all of the world’spotentiallyactivevolcanoeson land. InSARobservationsallowustobuildmodelsofsubsurfacemagmamovementpreceding, accompanying, and following eruptions –informationthatiscriticallyimportanttounderstandthestate of activity and anticipated hazards. Radar imagesthat allow us to monitor and characterize volcanicprocesses are also used to map the extent of eruptive

products, like lava and ash, during an eruption. Whencombinedwithothermeasurementsofvolcanicactivity,datafromNISARwillfacilitatethedevelopmentofmorerealisticdepictionsofactivevolcanoes,whicharecriticalforeruptionforesting.AllNISARdataproducts, includingtheInSARresults,willbe freelyavailable throughawebportal. Thisway, thenation’s investment in land surveys remotely acquiredfromspacecanbewidelyusedbyavarietyofagenciesandindividuals to monitor volcanic processes and mitigateassociatedhazards.

NationalAeronauticsandSpaceAdministrationFormoreinformation,visithttp://nisar.jpl.nasa.gov/applications

JetPropulsionLaboratory/CaliforniaInstituteofTechnology/Pasadena,California/www.jpl.nasa.gov

Mapshowingareasofvolcanoesintheworld[GlobalVolcanoProgram/SmithsonianInstitution;USCenterforDiseaseControl]

Morethan50volcanoesintheUnitedStateshaveeruptedoneormoretimesinthepast200years.ThemostvolcanicallyactiveregionsofthenationareinAlaska,Hawaii,California,Oregon,Washington,andWyoming.Unlikeothertechniquesthatrelyonmeasurementsatafewpoints,InSARproducesamapofgrounddeformationthatcoversaverylargespatialareawithcentimeter-tomillimeter-scaleaccuracy,evenoverremoteareaswithnoground-basedmonitoringresources.Thefiguretotherightshowsuplift(depictedascoloredfringes)oftheThreeSistersWildernessinOregonduring1995-2001,whichwasdiscoveredbyInSARandwouldnototherwisehavebeenknown.TheInSARdataindicatedtheintrusionofabout20millioncubicmetersofmagmaabout5kmbeneaththeground.Thelasteruptioninthisregionwasabout1500yearsago,andtherewillcertainlybeanothereruptionintheareainthefuture.Advancedknowledgeofmagmaaccumulationallowedforabetterground-basedmonitoringnetworktobeinstalled,andforbettercommunicationofpotentialhazardstothelocalpopulation.ImageCredit:USGS

Monitoring Volcanoes with InSAR