CraterLake

CraterLake

Aerialview

bathymetrysurvey

Location

Oregon

Coordinates

42°56′N122°06′WCoordinates:42°56′N122°06′W

Laketype

craterlake

Primarysources

precipitationonly

Primaryoutflows

evaporationonly

Basincountries

UnitedStates

Maxlength

6mi

km)

Maxwidth

5mi(8

km)

Surfacearea

sq

mi

km2)

Averagedepth

1,148ft(350

m)

Maxdepth

1,949ft(594

m)

Watervolume

cumi

km3)

Residencetime(of

lake

water)

250years

Shorelength1

21.8mi

km)

Surfaceelevation

6,178ft(1,883

m)

Islands

WizardIsland

1Shorelengthisnotawell-definedmeasure.

CraterLakeisacalderalakeintheU.S.stateofOregon.ItisthemainfeatureofCraterLakeNationalParkandfamousforitsdeepbluecolorandwaterclarity.Thelakepartlyfillsanearly4,000feet(1,220m)deepcalderathatwasformedaround5,677(±150)BCbythecollapseofthevolcanoMountMazama.

OnJune12,1853,JohnWesleyHillmanwasreportedlythefirstEuropeanAmericantoseewhathenamed"DeepBlueLake"inOregon.Thelakewasrenamedatleastthreetimes,asBlueLake,LakeMajesty,andfinallyCraterLake.

CraterLakeisknownforitsfamouspieceofdriftwoodnamedthe"OldManoftheLake."Itisafull-sizedtreethathasbeenbobbingverticallyinthelakeformorethanacentury.Duetothecoldwaterofthelake,thetreehasbeenratherwellpreserved.

Whilehavingnoindigenousfishpopulation,thelakewasstockedfrom1888to1941withavarietyoffish.Severalspecieshaveformedselfsustainingpopulations.

ThecommemorativeOregonStateQuarter,whichwasreleasedbytheUnitedStatesMintin2005,featuresanimageofCraterLakeonitsreverseside.

Geologicmapofthelakefloor

Dimensionsanddepth

Thelakeis5by6miles(8by

km)acrosswithanaveragedepthof1,148feet(350

m).Itsdeepestpointhasbeenmeasuredat1,949feet(594

m)deep,thoughaswithanylakeitsdepthfluctuateswiththeclimate,particularlyrainfall.ThismakesCraterLakethedeepestlakeintheUnitedStates,theseconddeepestlakeinNorthAmerica(GreatSlaveLakeisthedeepest)andtheseventhdeepestlakeintheworld(LakeBaikalisthedeepest).Thecalderarimrangesinelevationfrom7,000to8,000feet(2,130to2,440

m).

Geology

MountMazama,partoftheCascadeRangevolcanicarc,wasbuiltupmostlyofandesite,dacite,andrhyodaciteoveraperiodofatleast400,000years.ThecalderawascreatedinamassivevolcaniceruptionthatleadtothesubsidenceofMountMazamaaround5700BC:about50cubickilometers(12cubicmiles)ofrhyodacitewaseruptedinthisevent.Sincethattime,alleruptionsonMazamahavebeenconfinedtothecaldera.

Lavaeruptionslatercreatedacentralplatform,WizardIsland,MerriamCone,andother,smallervolcanicfeatures,includingarhyodacitedomethatwaseventuallycreatedatopthecentralplatform.Sedimentsandlandslidedebrisalsocoveredthecalderafloor.

Intime,thecalderacooled,allowingrainandsnowtoaccumulateandeventuallyformalake.Landslidesfromthecalderarimthereafterformeddebrisfansandturbiditesedimentsonthelakebed.Fumarolesandhotspringsremainedcommonandactiveduringthisperiod.

Alsoaftersometime,theslopesofthelake'scalderarimmoreorlessstabilized,streamsrestoredaradialdrainagepatternonthemountain,anddenseforestsbegantorevegetatethebarrenlandscape.

Somehydrothermalactivityremainsalongthelakefloor,suggestingthatatsometimeinthefutureMazamamayeruptonceagain.

PanoramicviewofCraterLake,withaportionoftheoriginalmountain'ssurfaceprofileseenatleft

AerialviewofCraterLake

Waterquality

Duetoseveraluniquefactors,mostprominentlythatithasnoinletsortributaries,thewatersofCraterLakearesomeofthepurestintermsoftheabsenceofpollutantsinNorthAmerica.

Secchidiskclarityreadingshaveconsistentlybeeninthehigh-20

metertomid-30

meter(80-115

ft)range,whichisveryclearforanynaturalbodyofwater.In1997,scientistsrecordedarecordclarityofmeters(142

ft).

Thelaketraditionallyhasrelativelyhighlevelsofdissolvedsalts,totalalkalinity,andconductivity.TheaveragepHhasgenerallyrangedbetween7and8.

Sacredsignificance

ThelocalKlamathtribeofNativeAmericanswhowitnessedthecollapseofMountMazamaandformationofCraterLakehavelongregardedCraterLakeasasacredsite.Theirlegendsandloretellsusthestoryoftwochiefswhowereengagedinabattleagainsteachother.Thatbattleresultedinthedestructionofoneofthechiefs'home,Mt.Mazama,andthecreationofCraterLake.TheKlamathpeoplealsousedCraterLakeinvisionquestsw