BulletinofGlaciologicalResearch21（2004）71−77
OJapanese Society of Snow and Ice

Shallowice・COredriアブ

ingat MountWrangell，Alaska

TakayukiSHIRAIWAl，Syosaku KANAMOFul，CarlS．BENSON2，DanieJSOuE2andYaroslav D．MURAVYEV31InstituteofLowTemperatureScience，HokkaidoUniversity，SapporoO60−0819Japan

2GeophysicalInstitute，UniversityofAlaska Fairbanks，KoyukukDrive，P．0．Box757320，Fairbanks，Alaska99775−7320USA
3InstituteofVoIcanology，RussianAcademyofSciences，Petropavlovsk−Kamchatsky，KamchatkaOblast683006Russia（ReceivedOctoberlO，2003；RevisedmanuscriptreceivedNovember6，2003）

Abstract

Duringthe2003summerweinitiatedathree−yearStudyofclimateandvoIcanichistoryonMt．
Wrangell，Alaska（60ON，144OW，4317m）．ItisbeingdoneincomparisonwithresearchonUshkovsky
VoIcano（568N，1600E，3903m），Kamchatka Peninsula，Russia．Both areice−COVered，andesitic vol−CanOeSOnthenorthPacificrim，at4000maltitudeandwithin6Qinlatitude．InJune2003aresearch
CampWaSeStablishedintheSummitCalderaofMt．Wrangellforthepurposeoficecoredrilling，radio

echosoundingoficedepth，andmaintenanceofpreviouslyestablishedphotocontrolpointsoncrater
rimsforuseinaerialphotogrammetry．A50micecoreofhighqualitywasobtainedinsections50cm

long，Withanewdrillwhichperformedverywell、Itwillbeanalyzedfor6180and6Daswellasfor

Chemicalanalyses of majorions and voIcanic ash traces．The core extended back to1981and

OVerlappedstratigraphicallywithcoreandpitstudiesdonefrom1961to19820nMt．Wrangell．The
lO−mdeeptemperaturewas−18．9OCandwasfoundtobehigherasmuchaslOCthanthoseobserved

in1970s．

1．lntroduction
TimeTSeries of decadalandinterdecadalclimatic

events（DICEs）in annualaccumulation rates andOfion chemistry，heavy metals，Waterisotopes，dust
COnCentration，bacteria，algae，pOllen and various
physicalproperties，and3）correcttheice−COreprOXies

in terms of strain history withlSt order 3D

WaterisotopesintheNorthPacificcryospherewere，
for the first time，reCOnStruCted from anice core
recovered fromthesummit plateau ofMt．Loganin

thermomechanically−COupledglaciermodel．

DICEs were also foundin anice core recoveredin aWrangellhas been studied for many yearS by C．S．

the1980s（Holdsworthetal．，1992）．TheNorthPacific

Crater glacier at Ushkovsky voIcano，Kamchatka

Duringthe2003summerweinitiatedathree−year

StudyofclimateandvoIcanichistoryonMt．Wrangel】，

Alaska．Summitglacier fillingthe caldera of Mount
Bensonandhiscolleaguesfromglacio−VOIcanologicalpeninsula（Shiraiwa et al．，2003；Shiraiwa and Viewpoints（e．g．Benson and Follett，1986）．The
Yamaguchi，2002）．Because the timeTSeries of recon− glaciologicalconditionatthesummitofMountWranT

StruCted accumulationratesboth at Mts．Logan andUshkovskyarenearlyanticorrelatedandthesynchroT
nouschangeswereconsideredtobegeneratedbythegell is quite similar to that we found at Ushkovsky（Mantua etal．，1997；ShiraiwaandYamaguchi，2002），

preliminaryresultsfromshallowice−COredrillingand
therelatedglaciologicalstudiesatthesummitglacier
OfMountWrangellin2003．

Pacific Decadal and Interdecadal Oscillations

Climatic conditions across the North Pacific are

expectedtohavebeeninteractedeachother．Inorder

to confirm the cross Pacific climate teleconnection

and to reconstruct atmospheric and marine environ−mentalchanges，Weneedseveraladditionalicecores
fromvariousregionsofAlaskaandKamchatka．

VOIcanoinKamchakta，therefore，the comparison of

thetwositeswillbesignificantinreconstructingthe

past proxy climate time−Series．Followings are the2．Regionalsettings
Mount Wrangell（600N，144OW，4317m），in theForthisaim，Weneedtol）drillice coresindry
SOutheasterninterior of Alaska，is a huge，glacier−SnOWfaciesofglaciersinAlaska（Mt．Wrangell，Mt． mantled，Shield voIcano（Benson and Motyka，1978）．
McKinley，Mt．Bona andothermountains）and Kam− Various kinds of glaciological and volcanological
Chatka（Mt．Ichinsky），2）analyzetheicecoresinterms Studies have been conductedbyscientists from Geo−

Z2

Bu11etin ofGlaciologlCalRe＄earCh

PhysicalInstitute，UniversityofAlaskaFairbanks．A

glacier filling tbe stlmmit caldera bas been studied

Since1960sbyC．S．Bensona‡ldbisco主1eagu鶴（Benson
andMotyka，1978；Benson，1984；BensonandFollett，
1986；Clarke et al．，1989）．Oneoftheimportantfind−ingsfromtheabove−mentionedstudieswasthatapart

Ofthesummitglacierwas categorizedin dry−SnOW
facies （Benson，1962）where melting of snow waslacking．Drillinganice−COreinthedrysnowfaciesis

anessentialconditionforahigh−qualitypaleoclimate

reconstruction，therefore，Mount Wrangelloffers an

idea王siteforthis kindofresearcぬin Aiaska，ぎurtberadvantageofMountl野range11asadriト

1ingsiteisthatitoffersanexceptionallyflatplacefor

drillingatanaltitudeabove4000m．Thisisparticular−

1yimportant foriceTCOre StUdies since complicatedtopographiesoftenfoundinmountainsmaketheinterL
pretationofproxyrecordsdifficult．Thesummitcalq
dera ofMountWrangelliscrownedbya4×6km

Oblong，1kmdeepglacier（Fig．1）．Thesnowsurfacein

thecalderaisrelativelyflat，Varylngfrom4000mto

4100min about3．5km．Ice flows out of the caldera

througbabreachoftbesoutbernrimattheheadof

tbe LongGlacierく28kmiong）（Fig．2）．Tbe caldera

mayhaveformedasrecentlyas20OOyearsago．This

Fig．1．Aerialview of Mount Wr・angellfrom southwest．

OriginalphotographispartoftheUnivcrsityofAlaska slong−termreSearChonMt−Wrangcllandwastakenby
AeroMapUS，aphotogrammetrycompanyinAnchor−age，Alaska．

youthfulcalderaremainsgeothermallyactiveandhas

threeprominent，pOSt−Caldera‡1，CraterSWitbsolねtara
activiもyalongthecrestofitsrim（BensonandMoty−ka，1978）．

Fig・2．PiarlemapOfthestlmmitgiacierofMountlVrangell．Thedriilingsiteandtbe
Strain−gridnetworkarede王10tedもyasolidsquareandso！idcirclesÅtoI）．Tbe
OriginaimapwaspreserltedatBe王1SO王1a一三dFollett（1986）．

73

Shiraiwa et al．
3．Members

5．tcecoredr‖ing

This project waslaunched as anInternational

A50−mlongice core was drilled by a newly

COllaborative program among U．S．A（Geophysical designedlight・Weight mechanicaldrill（Fig．3）toInstitute，University of Alaska Fairbanks：GI−UAF），
assess potentialoftheglacier developingin the caト
Russia（InstituteofVoIcanology，RussianAcademyof dera of Mount Wrangell．The drillwas specially
Sciences：IVTRAS）andJapan（Institute ofLowTem−
designed，by Mr．Kunio ShinboriofILTS−HU，for
perature Science，Hokkaido University：ILTS−HU）．
ice−COredrillinginhighmountainswhereweightofthe
The members ofthe2003field campaign are as fol・
drillsystemis crucialfor the operation．The drill
lows；
SyStemiscomposedofadrill−mOtOr，aChipchamber，acore−barrel，awinchwith200mcable，amaStanda
Dr．Takayuki Shiraiwa（ILTS−HU）Leader，COntrOl−unit．ThesystemweighsatotaloflOOkgand
Glaciologist
is back−paCkable by four people．It can be operated
Prof．CarlS．Benson（GI−UAF）Glaciologist
With a generator（700W）which addslO kg to the
Dr．DanielSolie（GI−UAF）Geophysicist
SyStemWeight．
Dr．Yaroslav D．Muravyev（IV−RAS）VoIcanologist／

Glaciologist

Mr．SyosakuKanamori（ILTS−HU）Graduatestudentat HokkaidoUniversity

Drs．Martin Truffer and Martin Peter Luethi，both from GI−UAF，Were also the members of the

projectbuttheycouldnotjointhefieldcampaigndue
totheirownfieldworksatotherglaciersinAlaska．

4．柑nerary

Wecharteredaturbo−ChargedSingleOtterplanefrom the Alaskan aircraft operator，Ultima Thule

Outfitters（Pilot：Mr．PaulClaus），and flewin the

personnel from Chitna to the northern foot slope ofMountWrangellat2900ma．s．1．，afterunloadingthe
equipmentatthesummitcaldera（June13）．Thisisfor

acclimatization．Weclimbedtheslopetothesummit
fromJune14to17bymakingthree camps；Campl（62003′41．0′′N；144DO2′57．0′′W；2976m），Camp2（62002′
53．2′′N；144003′45．3 W；3272m）and Camp3（62DOl′
50．4′′N；144005′27．9′′W；3685m）．We arrived at theSummit drilling camp at an altitude of4100m and
COOrdinates of 6lO59′53．6′′ N and144002′30．0〝 Win

June18．
Afterinstallingthecampfacilities，We Started a

Shallowice・COredrillingintheeveningofJune20andendedinthemorningof23．Thiswasfollowedbythe
radio−eChosoundingoficethicknessandtheborehole
thermometrytogetherwithinstallationofstrain−gridnetwork aroundtheborehole．The photographic andSeismologicalcontrolpointsattheNorthCraterwere
detected and surveyed with GPSinrelation to theboreholeattheendofcampaign．
Allthe personnel，a50m・longice core，and theequipment were flown out to Chitna by the sameaircraftinJune29．Theice core was storedin arefrigeratortruck at Chitna andthentransportedto
Anchorage．ItwasthenshippedtoJapaninafreezer
COntainer of a cargo plane，and arrived at freezer
facilityofILTS−HUinJuly7．

Fig．3．The portableice．core drilling system Dokodemo
Drillversion2 installed at the drilling site of theSummitglacierofMountWrangell．

The drilling was started from alevelof85cm
below the surface ofJune20．After the system wasassembled，WeStartedthedrillingonJune20at16：40
and endedit onJune23atlO：59．The drilling was
StOpped only once，because of a blizzard，from themorningtotheafternoonofJune22．Figure4shows

Cumulative net drilling time（h）versus depth（m）．It
took22hoursin totalto drillice coresdownto50．29

m．Average drilling speed，i．e．totaldrilling depth
divided by net drilling time，WaS2．27m per hour，WhichisfasterthanthatrecordedatKingCol，Mount

Loganin2002（Shiraiwa et al．，2003）．The faster

drillingspeedresultedfromthesimplicityofthenew

Bulletin ofGlaciologicalResearch

74

Nettime（h）

0 2 4 7 91214161921

Fig．5．A8Cmthickdustlayersfoundinthecorecovering

46．87r47．36mfromthesurface．Thisdustlayerisconsid−
eredtohavehadbeensuppliedtothedrillingsitewhen
a rock−aValanche occurred at the southwest face ofMountStanfordinAprilll，1981．

50mice core can cover the time series from1981to2003and overlapswith that drilledin1982by C．S．
Bensonandotherstoadepthof43m（Benson，1984）．

Fig．4．Cumulativenetdrillingtime（h）versusdepth（m）atMountWrangel12003．

Thisindicatesthatwecandatebacktoseveraltensof
yearswiththetwoicecoressofarobtainedatMount
Wrangell．
drill：inparticular，1ackofouterjacketshortenedthe
Bulkdensityprofileshowsatypicalprofilefoundservice time atthe surface．
inthedrysnowfacies：rapidincreaseupto550kgat
Theicecoresdrilledwereapproximately50cmin
12mandlessrapidincreasebelowthislevel（Fig．6）．
length andextremelygoodinquality．Avisible dirt
layerwasfoundatRunNo．95（drillingdepthsfrom Thedensityat50−mWaS700kgm￣3sothepore−Close
Off depth could belocated at65to70m whichis
46．87−47．36m）wherebrownto dark−browndispersed

extraordinarydeepatmountainglaciers．
Atotalof65icelayerswerefoundinthe50−miceparticles wereincluded with decreasing density up−ward（Fig．5）．This canbe assigned to the air−borne

dustlayers by a big rock−aValanche from Mountcore．Most ofthemarethinnerthanO．5mmbutsome
StanfordinAprilll，1981．Ifthisisthecase，preSent areasthick as5−10mm（Fig．6）．Thesearethemelt−
Thicknessoficelayers（mm）

Density（kgm￣3）

300 400 500 600 700

0

10 15

5

0

ヽ ●し
5

●●

10
15

l●

●

a q）
⊂）

●

㌔

●

￣￣

30

●
●

35

●●l

40
45

H

●

▲●

50
Fig．6．Bulk density，distribution and thickness oficelayersofthe50−mlongicecore．

Shiraiwa et al．

7ちfrozenicelayersandindicatethatthedrillsitesuffers
meltingalthoughtheintensityisextremelylow．

Temperature（℃）

Theicecorewi11besubjectedto6180，6D，majorions，traCe metals，a detailed density measurement−20 −19 t18 −17 −16 −15

Withxray，andcrystallographicobservationwiththin

0

SeCtionsatILTS，HokkaidoUniversity．

56−80reholetemperatures

10
15

Borehole temperatures were measured after theice−COre drilling was completed．We measured thetemperatures by two ways；One（methodl）is the

temporalmeasurementsofthe profilebyuslngther−mistorswithacompactdatalogger．Boththethermis−

torsandtheloggerwereattachedtotheheadofthe

ice−COre drillandloweredin the borehole．Afterit

reachedthebottomoftheborehole，Welifteditevery
5m andstopped at eachlevelfor aboutlhour．The

20
）

卓 25
包 1〉 凸3035
40

firstmeasurementwasdoneinJune23justafterthe

45turbancebydrilling，Werepeatedthismeasurementin
June25whenweusedaclimbingrope，insteadofthe
drillanddrillTCable，inordernottodisturbtheairin

50

drilling・Becausewewereafraidoftemperaturedis−

theborehole．Theotherwayoftemperaturemeasure−ments（method2）was the continuous measurements

Fig．7．Air temperature profilesin the 50−m borehole．
Solid squaresindicate the temperature measured bymethod2，Whiletheopensquaresby methodl．

at fixed depths with datalogger．A totalof eightplatinum resistance sensors were connected to thedataloggeratthesnowsurfaceandindividualsensors

profiledownwardwiththe sametemperaturegradi−
ent，the thickness of the glacieris calculated to beaboutlOOO m，by assuming that the bottomis at
Werelocatedat20，15，10，8，6，4，2andlmbelowthepressure melting point and the vertical temperature
Originalsnow surface ofJune20．We recorded thegradientthroughouttheglacierisconstant．
temperaturesduringlOminuteintervalsfromJune23
at17：00toJune26atll：40．Theintervalwas then 7. Rapid static GPS survey for strain‑grids
Changed to3hours and restarted for measurement
untilMay2004．Theaccuraciesofthemeasurements
Weinstalled four strain−grid pointsin order toare±0．50Cfor methodland±0．lOCfor method2．

Figure7showsthetemporalprofilesofthetwo

measurethestrainneartheborehole（AtoD：Fig．2）．

Thefourstraingridpointswerelocatedtothedrilling

differentmeasurements．ThelO−mdepthtemperature Site（DS）bya set ofsurveyGPS（TOPCON）with a
WaS−18．9OCbythe methodlforJune25at20：00， rapidstaticmethod（June24）．TheDSwasthenlocat−
and−18．2OCbythe method2throughthemeasure・ ed relative to BM3at the North Crater（June25）．
ment period・Sinceit was−200Cin1961，1965and Tablelshows the exact coordinates of the survey
1976（BensonandMotyka，1978）itmayindicatethat
point for the future survey．We could measure thethetemperatureincreasedbyatleastlOCduringthe
past threedecades．

Thetemperaturegradientsfrom20to45m are

COnStant at O・2OC perlO m．If we extrapolate theabsoluteflowvectoraswellasstrainbythis strain

gridnetwork．Eachsurveypointwaslocatedbya3−rr）
SurVeypOleandmarkedbya3．5m−longwoodmarker
forre−SurVeyin2004．

Tablel− Coordinatesofthemeasuredpoints．
Latitude（O）

Longitude（0）Altitude（m）

Drillingcamp 6lO59′53．617814′ N 144DO2′30．035349′′W 4099．906m
A

62000′03．088954 ′N 144002′02．354940′′W 4097．546m

B

6lO59′40．087682′′N 144002′10．420254′′W 4090．913m

C

6lO59′44．123173′′N 144002′58．381445′′W 4103．235m

D

62POO′06．774097′′N 144002′49．137880′′W 4111．097m

Bu】letir10fGlacio】ogicalResearch符

8．Snowpitstudy

tureinJune25．Thedepthof28．5cmisassignedto

theactualtopoftheicecore．

Because theice core began85 cm below thesurfaceofJune20，WeeXCaVatedl．6m−deepsnowpit

9．Comparison withotherice・COredri＝ngsites

to17：00（Fig．8）．Studieditemsarestratigraphy，SnOW

It was found that the summit glacier at Mount
Wrangell was characterized by dry snow with few

andstudieditneartheboreholeonJune25from14：45

temperaturemeasurementsatlOcminterval，density

measurement at3cminterval，and snow sampling．

melt−frozenicelayers．Thisisparticularlyimportant

foricecorestudysinceintensivemeltingcoulddisturb
anykindsofsignalsintheglacier．Theadvantageof
the present site becomes clear by comparing its
freshsnow（Op21．5cm）andathinicelayer（21．522．5cm）wastentativelyassignedtothesurfaceofJune20． glaciologicalparameterswiththoseobtainedatotherdrilling sites which are located along the North
Thepitthereforecoverstheuppermostpartoftheice
Pacific coast（Table2）．
corewhichwasnotobtainedbythedrilling．
AnnualaccumuユationrateisthehighestatWran−
Figure8indicatesthesnowdensityandtempera−
Although we could not decide the snow surface ofJune20veryclearly，aboundarybetweenthesurface

gellamongthethreedrillingsites．Itisl．3ma1w．e．
inthecenterofthecaldera（BensonandMotyka，1978）
andO．86marlw．e．inthe1982coresite（Fig．2）（Ben−SOn，perS．COmmu．）．This willcontribute to high−resolution of past climate reconstruction．ThelO−m

Density（kgm−3）

200

0

400

600

0

deep snow temperatureisthelowestin splte Of thefact that the siteislower than King Colof Mount
Logan．Densification at Mount Wrange11is theslowest when we fit the verticalprofiles of firn−

20
40

density at three siteswith mean−Square apPrOXima−
tionp＝Pi（1、Cse一γh）wherepiisthedensityofpureice（918kgm￣3）Cstheiceporosityatthesurface，γ60⊂） 8 80手

theindexinthe density−depth profile approximation

首100

and hthe depth．

）

Theice thickness at the drilling siteis stillun−

120

known．Thisis because past attemptsin radio−eChosoundingweren tsuccessfulatMountWrangell：bed

140

reflectionhasneverbeenobtainedatthecenterofthe

160

calderaglacier（e．g．Clarkeetal．，1989）．Presentstudy

confirmsthelacknessofbedreflectionatthedri11ing

180
−20

−15

−10

−5

site．Clarkeetal．（1989）estimatedthethicknessofthe0

Temperature（℃）
Fig．8．Density（solidsymbol）andsnowtemperature（opensymbol）ofthesurfacel．6mnearthedrillingsite．

glacierasthickas900m．Thisismuchthickerthan
thoseatKingColandUshkovsky，andimpliesthatthe
glacieratMountWrangellstoreslongertimehistoryof climate and environmentalconditions．

Table2．Glaciologicalfeaturesatthreedrillingsites，Wrangell LoganKingCol Ushkovsky
Latitude61059′54′′N

60035′20′′N

56004′29′′N

Longitude

144002′30′′W

140036′15′′W

160028′04′′E

4100

4135

3900

1．2＊＊

0．54＊＊＊−18．0＊＊＊＊−15．8＊＊＊

Altitude（m）
Annualaccumulationrate（maJIw．e．）

10rmdepthsnowtemperature（OC）
Snowtemperatureamplitude（OC）
Initialdensity（kgm3）

1．3■−0．86＝＊＊＊＊
【18．9
n．a．

n．a．

16＊＊＊

370

420＝＊＊

450＊＊春Initial porosity c

0．63

0．58＊＊＊＊

0．55＊＊＊

Densificationfactorγ

0．028

0．031

0．038＊＊＊

Thicknessoftheglacier（m）

n．a．

Ca220＊＊＊＊

Ca240＊＊＊

7．02事＊＊＊＊

rLa．

0．12＊＊＊

Geothermalheatfiux（Wm2）＊BensonandMotyka（1978）；＊＊GotorAzuma et al．（2003）；＊＝Shiraiwa et al．（2001）；＊＊＊＊Shiraiwa et al．（2003）；＊＊＊＊＊Clarke et al．（1989），…榊 Benson（personcommu．）

Shiraiwa et al．

10．Concluding remarks
We started US−RusSia−Japan joint glacio・

77

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Benson，C．S．（1962）：StratigraphicstudiesinthesnowandfirnoE
theGreenlandIceSheet，SIPRE／CRRELResearchReport，
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AnnualReport，1−25．
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Clarke，G．K．C．，Cross，G．M．and
Benson，C．S．（1989）：Radar
Weareplanningtodrilla300−mdeepicecorein
imaging of glaciovoIcanic stratigraphy，Mount Wrangell
the year of2004at the same glacier．This willbe
Caldera，Alaska：Interpretation modeland results．Jour．
associated with glacier dynamic observations which
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wi11beessentialfortheinterpretationoftheicecore．
Goto−Azuma，K，Segawa，Tリ Shiraiwa，T．，Matoba，S．
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Okeru seppyo koa kaiseki（Ice core analyses at Mount
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Logan，Canada）．Preprintsofthe2003Conference，JapaneseSocietyofSnowandIce，p，3（InJapanese）．
We wouldlike to thank Prof．Takeo Hondoh，Holdsworth，G．，Krouse，H．R．and Nosal，M．（1992）：Ice coredirectoroftheInstituteofLowTemperatureScience，
ClimatesignalsfromMountLogan，Yukon，AD1700−1987．
In Climate Since A．D．1500，R．S．Bradley and P．D．Jones
Hokkaido University，for his continuous support for（Eds．），Routledge，London，483−504．
theiceTCOre drilling programin mountains of the
Mantua，N．J．，Hare，S．R．，Zhang，Y．，Wallace，North Pacific rim．We are alsoindebted to Prof．
Francis，RC．（1997）：APacificinterdecadalclimateoscillaL
ShunichiAkasofu，directoroftheInternationalArctic
tion withimpacts on salmon production．Bull．Amer，
ResearchCenter，UniversityofAlaskaFairbanks，forMeteorol．Soc．，78，1069−1079，
Shiraiwa，T．，Murav yev Y．D．，Kameda，T．，Nishio，
hisfinancialsupportfortheAmericanmembersinthe
project．WethankMr．KunioShinbori，theworkshop Toyama，Y．，Takahashi，A．，Ovsyannikov，A．A．
Salamatin，A．N．andYamagata，K，（2001）：Characteristics
technician atILTSTHU，for providing us with the
Of a crater glacier at Ushkovsky voIcano，Kamchatka，
portableice−COre drilling system without which thisRussia，aSreVealedbythephysicalpropertiesoficecores
Studywasn tpossible．Mr．PaulClausofUltimaThuleandboreholethermometryJ，Glaciology，47（158），423−432，
Shiraiwa，T．and Yamaguchi，S．（2002）：Reconstruction of
Outfitters supported our flight operation with his
glaciermassbalancesandclimatechangesintheKamchatr
excellent and powerfulaircraft．Japanese members
ka PeninsulaJ．Geography，111（4），476485（InJapanese
Werefinanciallysupportedby Grant−in−Aid forCrea−
withEnglish abstract andfigurecaptions）．
tive Scientific Research（Project no．14GSO202；PI：
Shiraiwa，T．，Goto−Azuma，Kリ Matoba，S．，Yamasaki，T．，
Takeo Hondoh）from the Ministry of Education，
Segawa，T．，Kanamori，S．，Matsuoka，K．and Fujii，Y．
（2003）：Ice core drilling at King Col，Mount Logan2002．
Science，Sports，CultureandTechnologyofJapan，and
Bu11．Glaciol．Res．，20，57−63．
theInoueScientific FieldStudyFoundation．

VOIcanologicalstudyin the North Pacificin which
Mount Wrangell was the main target for the next