Table Of ContentShort Coursei n Geology: Volume 1
Volcanic Hazards
Robert I. Tilling, Editor
Q ShCorotu Prrsees aettn htee d
28th International GeologicalC ongress
WashingtonD, .C.
American GeophysicalU nion, Washington, D.C.
MariaL uisa Crawforda ndE lainPea dovani
ShorCto ursSee riEedsi tors
LibraoryfC ongresCsa taloging-in-PDuabtlai cation
Volcanic 1Rh oabezratIr .Td isl leidnigt,o r.
p. em.
Bibliogpr.a phy:
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CO1NTNTS
FOREWORD AND ACKNOW(cid:127)
CHAPTER 1. INTRODUCTION AND OVER(cid:127)
Robert I. Tilling 1
CHAPTER 2. VOLCANIC AND RELATED HAZARDS
William E. Scott
CHAPTER 3. VOLCANIC-(cid:127) ZONATION AND LONG-TERM FORECASTS
William E. Scott
CHAPTER 4. VOLCANO MONITORING AND SHORT-TERM FORECASTS
Norman G. Banks, Robert I. Tilling, David H. Harlow,
and John W. Ewert
CHAPTER 5. RECENT CASE HISTORIES
Raymundo$ . Punongbayana nd Robert I. Tilling 81
CHAPTER 6. $CIEb{'Ilb'IC AND PUBLIC RESPONSE
Robert I. Tilling and Raymundo$ . Punongbayan lOS
RE(cid:127)RENCES (For all chapters) (cid:127)07
iii
FOREWORD AND ACKNOWLEDG(cid:127)(cid:127)S
The catastrophiecr uptiono f Mount St. Helenso n May 18, conductedb y the U.S. GeologicalS urvey in March 1984
1980, inauguratedth e worstd ecadeo f volcanicd isastersa nd (Williams and Kitemiller, 1984).
crisess ince1 902,t he yearw hent hreee ruptionsin a 6-month This short course could not have been offered and
period (Mont Pel(cid:127)e, Martinique;S oufri(cid:127)re, St. Vincent; and conductedw ithout the participationo f many groupsa nd
Santa Mafia, Guatemala) claimed more then 36,000 human individuals.T he organizingc ommitteeosf the 28thI GC and
lives (Tilling, 1989, in press). The volcanic disastersa nd theI AVCEI GeneraAl ssemblyo n ContinentaMl agmatisma nd
crisesi n the 1980's greatly enhanceds cientifica nd public the Division of Earth Sciences(U NESCO, Paris) provided
awarenesso f volcanic eruptions and associatedh azards, encouragemenatn d logisticals upport.M y deepa ppreciation
spurreda dvancesin volcanologya ndt he establishmenotf new goest o my Co-ConvenorR, aymundoS . Punongbayana,n dt o
volcano observatories, and launched numerous international the lecturersN orman G. Banks, John Ewert, David Harlow,
conferencess, ymposia,a nd workshopso n volcanic-hazards andW illiam E. Scottf or takingt imef romt heirb usys chedules
topics. Thus, it was fitting that the organizerso f the 28th to serveo n the short-courstee am. One or mored raftc hapters
InternationaGl eologicalC ongress[I GC] (WashingtonD, .C., of theses hort-coursneo tesw erer eviewedb y StevenB rantIcy,
July 9-19, 1989) and the General Assemblyo n Continental John J. Dvorak, C. Dan Miller, L.J. Patrick Muffler,
Magmafismo f the InternationaAl ssociationo f Volcanology ChristopheGr . Newhall,D onaldW . PetersonP, atrickP ringle,
and Chemistryo f the Earth's Interior [IAVCEI] (Santa Fe, andD onaldA . Swanson--alol f the U.S. GeologicaSl urvey
New Mexico,J une2 5-July1 , 1989)d ecidedt o offer a jointly (USGS). Their critical commentsa nd helpful suggestions
sponsoredS hort Courseo n VolcanicH azards. materially improved the content and presentationo f the
The chaptersh ereinp rovidet hef rameworkfo r thet wo-day chapters. Specialt hanksg o to Manuel Nathenson( USGS,
shortc ourset,o be convenedJ uly 2-3, 1989, at the Collegeo f Menlo Park) for technical advice and assistance in the
SantaF e, New Mexico. This shortc oursea, lsoc o-sponsored preparatioonf camera-reacdoyp y,a ndt o PamelaH anback
by the Division of Earth Scienceso f the United Nations (American GeophysicalU nion, Washington,D .C.) for the
EducationalS, cientifica nd CulturalO rganization[ UNESCO] carefulp aste-upo f thisv olume.
(Paris), will be open to registrantso f either the IGC or the The governmentosf CanadaI,c eland,F rance,I taly, Japan,
IAVCEI meeting. Obviously, the vast topic of volcanic United Statesa nd severalo therc ountriesh elpedt o provide
hazardsc annotb e treatedc omprehensiveilny only two days. and/or coordinate logistical support in connectionw ith
The primary aim of the shortc oursei s to review someb asic scientificr esponsetso somev olcanicd isastersa ndc risesin the
principlesa ndm ethodso f the mitigationo f volcanich azards, 1980's. In this regard, the following international
with speciafl ocuso n the developingc ountriesw, hichc ontain organizationsp layed especially prominent roles: Nordic
most of the world's dangerousv olcanoes. In addition to Volcanological Institute, Reykjavik; Division of Earth
lectures and classroom discussion, the short course also Sciences, UNESCO, Paris; Office of the United Nations
includeas half-dayfi elde xcursiotno examinev olcanicd eposits Disaster Relief Co-ordinator, UNDRO, Geneva; and World
and featuresa nd to demonstrates omev olcano-monitoring Organization of Volcano Observatories (WOVO), a
measurements. commission of the IAVCEI.
These short-coursen otesp ertain only to the classroom Finally, on behalf of all the memberso f the short-course
activitiesa ndm ayb e supplementebdy unpublishehda nd-outs team, I wish to expresso ur appreciationfo r the studiesa nd
givent o thep articipants[.T hei nteresterde aderm ayo btaina observationosf eruptivep henomenam adeb y our colleagues
set of theseh andoutsa t no cost by contactinga ny of the working at active or potentiallya ctive volcanoesa roundt he
authors.]B ecauseo f spacea nd time limitations,t he notesa re world. Significant advancesi n volcano monitoring and
necessarilbyr iefa ndg eneralt;h eya ren oti ntendedto constitute eruption prediction will come only from an improved
completec overageo f the topics,b ut insteadt o providea understandinogf the workingso f manyi ndividualv olcanoes,
contextf or discussiona nd to point to directionsf or more rathert hano f only a selectf ew.
specializedan dd etaileds tudies(g iveni n REFERENCES).I n
somer espectsth, eS antaF e shortc oursefo llowst hec overage
andfo rmaotf t hev olcanhica zardcso mponeonft th e; uccessful RobertI . Tilling, Editor
Geologic and Hydrologic Hazards Training Program Menlo Park, California
iv
Short Courses in Geology Volcanic Hazards Vol. 1
CHAPTER 1. IN(cid:127)ODU(cid:127)ON AND OVERVIEW
RobertI . Tilling
U.S. GeologicaSl urveyM, enloP ark,C alifornia9 4025
Introduction 1987). Table 1.1 summarizes the general qualitative
relationshipbs etweenv olcanot ype, lava compositiona, nd
Volcanismh asp layeda majorr ole in the geologicp asto f eruptions tyle;f or mores pecificin formationa boutv olcanoes
ourp laneta, se videncebdy thev olcanico rigino f mucho f the and their productsa nd behavior,t he readeri s referredt o
Earth'sc rust,a bovea nd below the sea. On a geologict ime volcanologtye xtbook(se .g.,M acdonald1, 972;B ullard,1 984;
scale,v olcanic activity has benefitedm ankindb y creating Williamsa ndM cBirney,1 979;F ishera ndS chmincke1, 984).
scenica ndf ertile terranesth at fostera nd sustainth e growtho f Manyg eoscienfismtsa pi n ancienvt olcanitce rraneosr conduct
civilization. On a human time scale, however, volcanic researcho n volcanica nda ssociatemd agmaticp henomentah at
eruptionasd verselya ffects ocietyif theyo ccuri n populated occurredi n the geologicp ast, but only a few work in
and/orc ultivatedr egions. volcanology(a s defineda bove),a nd fewer still are directly
More than 1,300 volcanoesa re known to have erupted involved in the assessmenat nd/or monitoring of volcanic
duringt he past 10,000y ears;a bouth alf of theseh aveb een hazards.
active within recordedh istory. Two thirds of the active The scienceo f volcanologyh asb eena ssociatewd ith, and
volcanoesa re located along or near the tectonic-plate catalyzebdy ,v olcanihc azardasn dd isastersF.o re xampleth, e
boundarieisn the circum-Pacifirce gion. Typically,a bout5 0 first accurated escriptioonf an eruptionw asc ontainedin two
volcanoesa re active each year, and this averagee ruption lettersfr omP linyt heY oungerto theR omanh istorianT acitus,
frequenchya sn otc hangeadp preciabilny historicti me( Simkin describintgh ed eatho f hisu nclet,h ef amouss cholaPr linyt he
et al., 1981). Peterson( 1986, Table 15.1) hase stimatedt hat Elderb, ya sphyxiatiownh ileo bservintgh eA .D. 79 eruptioonf
about3 60 million people--abou1t 0 per cent of the world's Vesuvius(S igurdssoent al., 1985b). Yet, the 1815e ruption
population--livoen or ne(cid:127) potentiallyd angerouvso lcanoes. of Tambora( SumbawaI,n donesia)--thlea rgesta ndd eadliest
With the rapidlye xpandingw orld populationm, ostlyi n the eruptioinn recordehdi story--halidtt les cientifiicm pacbt ecause
already densely populatedd evelopingc ountries,a nd a because of the volcano's remote location, poor global
continuationo f the presente ruptionf requencym, any more communicationsa, nd the immature status of the natural
millionso f peoplew ill bet hreatenebdy futurev olcaniacc tivity. sciencesa t the time (Simkina ndF iske, 1983). No scientific
Because the "total abandonment of all volcanic areas...is not expeditiowna sd ispatchetodT amborua ntil1 847a, nda nother
realistic"(W alker,1 982,p . 156),t hes cientificc ommunitya nd eighty earsp assebde foreth ee xpeditiorne porwt asp ublished
the civil authorities face a chronic and increasingly acute (Zollinger1, 855)! In contrastt,h e 1883e ruptiono f Krakatau
problemin copingw ithp otentiahl azardfsr omf uturee ruptions. (SundaS traitsI,n donesiaa) ttractedtr emendoussc ientifica nd
public interest. It promptedt he first well-organized
VolcanologyS: tudyo f EruptiveP henomena investigatioonfs a volcanicd isastearn di tsa ftermathb,e cause,
by the end of the 19th century,g lobalt ransportatioann d
The science of volcanology, in the broadest sense, communicatiohnasd i mproveds ubstantialdlyu ringa n erao f
encompassaelsl studieso f magmatica ndv olcanicp henomena rapids cientifiacn dt echnologicaadl vance(sF ranciasn dS elf,
in the mantlea nd crust. For the purposeso f the shortc ourse, 1983; Simkin and Fiske, 1983). Several comprehensive
volcanologyis more narrowlyv iewed as the studyo f the scientifics tudiesw ere publishedw ithin five years of the
transporat nd eruptiono f magma( Sigurdsson1, 987), with disaste(re .g., Verbeek,1 885;J udd,1 888;S ymons1, 888).
emphasios n activeo r potentiallya ctivev olcanoes(T illing, Volcanology truly began to emerge as a modern,
multidisciplinarsyc iencew ith the establishmenotf volcano
Publisheidn 1989b y theA mericanG eophysicUaln ion. observatorieins J apana ndH awaiii n 1911,i n parts purredb y
Short Courses in Geology Volcanic Hazards Vol. 1
INTRODUCTION AND OVERV(cid:127)
TABLE 1.1. Generarle lationsMpbse tweenv olcanoty pesp, redominalnatv a,e ruptions tylesa, ndc ommon
eruptivec harac(cid:127)stics( afterT illing,1 987,T able2 ).
Predominant lava
Volcano , Eruptions tyle Commone ruptive
type Composition Relative characteristics
viscosity
Shiel1d Basaltic Fluidal Generallnyo n-explosive Lavaf ountainlsa,v af lows
to weaklye xplosive (long),l aval _(cid:127)keasn dp ools
Andesitic Less Generalleyx plosivbeu t Lavaf lows( medium)e, xplosiw
fiuidal sometimenso n-explosive ejectat,e phrafa lls,p yroclasti½
flows ands urges
Compos2i te
Dacitic Viscous Typicallyh ighlye xplosive Explosivee jectat,e phrafa lls,
to to butc anb en on-explosive, pyroclastifclo wsa nds urges,
Rhyolitic Very especiallayf tera large lavaf lows( short)a ndl ava
viscous explosion domes
1Generalollyc ateindt hein terioorft ectonpicla te(s" intraplaaten"dp) resumteodo verli"eh ost potsb,"u t
alsom ayo ccuri n othert ectonics ettings(e .g.,G alapagosIc, elandK, amchatka).
2Generalo(cid:127)yc ateadlo nogr n eatrh eb oundaroifec so nvergteenctt onpicla te(ss ubductzioonne sa)l;s oca lled
stratovolcanoes.
the three volcanic disasters in 1902 in the Caribbean-Central andc ausec orrespondingfleyw erh umanc asualtieasn ds maller
Americanre gion( Apple,1 987;T illing, 1989,i n press). economic loss (Figures 1.1 and 1.2). However, the
perceptionasn d definitionso f what constituteas "disaster"
(Figure 1.1) differ widely among governmento fficials,
Volcanic and Related Hamrds journalistsa,n dt hep eoplea ffectedth emselvesA. lso,t herei s
no generaal greemenot n whati s meantb y "peoplea ffected"
Let us first m_(cid:127)ke clear the distinction between hazards and (Figure 1.2) by a disaster( killed, injured,d isplacedl,o st
risks. The following definitionsa re adaptedf rom Fournier familym emberl,o stl ivelihoodi,n convenienceedt,c .?).T hus,
d'Albe (1979)' thes tatisticavla lidityo f thed atas hownin Figures1 .1 ands1 .2
must be consideredin light of thesei nherentv agariesi n
Hazard the probabilityo f a given area being affectedb y accountosf disastersN. onethelessth, eg enerapl atternss hown
potentiallyd estructivveo lcanicp rocesseosr products in theset wo figuresp robablyw ouldh old,r egardlesos f the
withina givenp eriodo f time. definitions and data sets used.
Risk the possibility of a loss--sucha s life, property, The deadlieste ruptioni n history( Tambora,I ndonesia,
productivec apacitye, tc.--withinth ea reas ubjectto the 1815)k illed 92,000 people,c omparedw ith 500,000k illed in
hazard(s). Assessmenotf risk l(cid:127)nvolvesth e the worst hurricane (Ganges delta, Bangladesh, 1970).
consideration of the relation: risk -- (value) x Perhapsth ew orstn aturald isasteirn historyw ast heH uahsien
(vulnerability)x (hazard),w herev aluem ay include earthquak(eS hensi,C hina) in 1556, whichk illed moret han
the numbero f lives, propertya nd civil works,a nd 820,000p eople( DeNevi, 1977). More recentlys, omeo utside
productivec apacityth reateneda,n dv ulnerabilityis a observerssp eculatteh ata sm anya s8 00,000p eoplep erishedin
measureo f the proportion(0 to 100 %) of the value the? .8-magnituTd(cid:127)en gsha(nC hina)earthquiank Jeu ly1 976,
likely to be losti n a givenh azardouesv ent. event hougho fficialC hinesefi guresp lacet hen umbero f deaths
Comparedw ith other natural or man-made" disasters," at about2 40,000( Shi Diguang,1 987).
thosec ausedb y volcanica ndr elatedh azardsi,f considereodn For the United States, the annual economic loss from
a globalb asis,o ccuri nfrequently", affect"f ar fewer people, volcanice ruptionpsr obablyis an ordero f magnitudsem aller
Short Courses in Geology Volcanic Hazards Vol. 1
T]LLINO 3
1950D'0
o
1970B'1
1980'/1
o (I) c
c ,--
or) CT .c '-
(cid:127) .c o, (cid:127) c
(cid:127) E -
:(cid:127) '-- O (I) '(cid:127) (I) O OM
c ß G u oe
-I IJ. M ß c
X --
Fig. 1.1. Averagen umbeor f recorded"d isasteerv entsp" ery eari n thew orld( seet ext);o thert hanf or
volcanice ruptiontsh ed ataf or the 1980'sc overo nlyt hep eriod1 980-81. (Modifiedfr omW ijkmana nd
Timberlake1, 984,F ig. 1). In thisf igure,a "disasteerv ent"r eferst o a "manifestatioonf an interaction
betweene xtremep hysicaol r naturapl henomenaan da vulnerablhe umang roup"t hatr esultsin "general
disruptioann dd estructiolons, so f lifea ndl ivelihooadn di njury."(O 'Keefaen dW estgate1,9 76).,
thant hatf rome arthquakewsh, ichi n turni s nearlya no rdero f likely to die from a hearta ttackw hile shovellings nowo r a
magnitudlee sst hant he lossf rome itherf loodso r ground lightnings triket hanf rom eithera n earthquakoer a volcanic
failures( Haysa ndS hearer1, 981). White andH aas( 1975) eruption. For more denselyp opulatedc ountries( e.g.,
suggestht att hea veragpee rsonliv ingi n theU .S.i s muchm ore Indonesia,P hilippines,a nd Japan),h owever, volcanic and
Fig. 1.2. Numbeor f people" affectedp"e ry earb y disasternsa, turaal ndm an-mad(es eet ext);v olcanic
disasterasr ei ncludedin thec ategory" Otherd isasters.B" etweenth e 1960'sa nd 1970'st,h e numbeor f
peoplaef fecteeda chy earn earlyd oubled(.F romW ijkmana ndT imbefiake1,9 84F, ig.4 ).
Short Courses in Geology Volcanic Hazards Vol. 1
4 INTRODUCTION AND OVERVIEW
TABLE 1.2. Somen otablev olcanicd isasterssin ceth ey earA .D. 1000i nvolvingfa talities(f iguresro undedo ff
to nearestte n). (Modifiedf romY okoyamae t al., 1984,T able1 ; UNDRO/UNESCO,1 985,T able 1).
Primaryc auseo f death
Volcano Country Year Pyroclastic Debris Lava Post-eruptionT sunami
How How How starvation
Merapi Indonesia 1006 * 1,000
Kelut Indonesia 1586 10,000
Vesuvius Italy 1631 *'18,000
Etna Italy 1669 *'10,000
Merapi Indonesia 1672 *300
Awu Indonesia 1711 3,200
Oshima Japan 1741 1,480
Cotopaxi Ecuador 1741 1,000
Makian Indonesia 1760
Papadajan Indonesia 1772 2,960
Lakagigar Iceland 1783 9,340
Asama Japan 1783 1,150
Unzen Japan 1792 15,190
Mayon Philippines 1814 1,200
Tambora Indonesia 1815 12,000 80,000
Galunggung Indonesia 1822 4,000
Nevado del Rufz Colombia 1845 1,000
Awu Indonesia 1856 3,000
Cotopaxi Ecuador 1877 1,000
Krakatau Indonesia 1883 36,420
Awu Indonesia 1892 1,530
Soufri(cid:127)re St. Vihcent 1902 1,560
More Pel(cid:127)e Martinique 1902 29,000
SantaM afia Guatemala 1902 6,000
Taal Philippines 1911 1,330
Kelut Indonesia 1919 5,110
Merapi Indonesia 1951 1,300
Lamin(cid:127)on PapuaN ew 1951 2,940
Guinea
Hibok-Hibok Philippines 1951 500
Agung Indonesia 1963 1,900
Mount St. Helens U.S.A. 1980 ***60
E1Chich6n Mexico 1982 > 2,000
Nevado del Rufz Colombia 1985 > 22,000
TOTALS 65,140 53,900 28,000 89,340 53,090
* Includedse athfsr oma ssociatemdu dflowsh;o wevetrh, ev alidityo f the1 006e ruptiohna sb een
questioned(D jumarmae t al., 1986).
** Includedse athfsr oma ssociateedx plosionasn d/omr udflowa ctivitye; stimateasr eu nreliablaen d
probablyt ooh igh.
*** Principacl auseosf deathsw erea laterallyd irectedb lasta nda sphyxiation.
Short Courses in Geology Volcanic Hazards Vol. 1
TR2.,ING
TABLE 1.3. Humanf atalitiesfr omv olcanica ctivity1, 600-1986g, roupeda ccordinagc cordintgo
primaryc auseso f death. (M(cid:127)ed from Blong,1 984,T able 3.2).
Primaryc ause 1600 - 1899 1900 - 1986
Pyroelastifclo wsa ndd ebrisa valanches 18,200 (9.8 %) 36,800 (48.4 %)
Mudflows (lahars)a nd floods 8,300 (4.5 %) 28,400 (37.4 %)
Tephraf allsa ndb allisticp rojectiles S,000 (4.3 %) 3,000 (4.0 %)
Tsunami 43,600 (23.4 %) 400 (0.5 %)
Post-eruptiosnt arvationd, iseasee, tc. 92,100 (49.4 %) 3,200 (4.2 %)
Lava flows 900 (0.5 %) 1O 0 (0.1%)
Gasesa nda cidr ains ................ * 1,900 (2.5 %)
Othero r unknown 15,100 (8.1%) 2,200 (2.5 %)
TOTALS 186,200 (100 %) 76,000 (100.%)
Fatalitiesp ery ear 620 880
(average)
*Includest he deathsc ausedb y lethal gasb urstsa t two volcanic-cratelra kesi n Camcroon,3 7,
Lake Monoun,A ugust1 984 (Sigurdssoent al., 1987b);a nd> 1,700,L ake Nyos,A ugust1 986
(Klinge t al., 1987). The lethalg as( carbond ioxide)in botht hesec asesis of volcanico rigin,b ut
thec ausativme echanismosf gasr eleasea ren otw ell understood.
related hazards have much greater potential for causing Sincet he year A.D. 1000,m oret han3 00,000p eopleh ave
catastropheicc onomiclo ssa ndh umand eaths. beenk illedd irectlyo r indirectlyb y volcanica ctivity. Table 1.2
The main types,n ature,a nds electede xampleso f volcanic dearly showst hatt he eireum-Pacifivco lcanicz one( "Ringo f
and related hazards are discussed in CHAPTER 2. Fire") has sustainedth e greatesth umanl osses;in deed,a bout
two thirdso f all eruption-relatedde athso ccurredin only three
Historical Review of Volcanic Hazards and Disasters countries( Colombia, Indonesia,a nd Japan). Blong (1984,
Table3 .2) analyzedth e humanf atalitiesf rom volcanica ctivity
Thei ncidencoe f humanfa talitiesfr ome ruption(sT able1 .2) for the period 1600-1982i n termso f the causativev olcanic
providest he only relatively completeb asist o evaluatet he hazards. A modified tabulation of his analysis, updated
frequencya nd magnitudeo f volcanicd isastersc; omparable through1 986( Table1 .3),p ermitsth ef ollowingo bservations:
information on the economic losses incurred and attendant 1) The averagen umbero f fatalitiesp ery earf or the 1900-1986
adversee nvironmentaiml pactsis fragmentaryo r unavailable. period (880) is higher than that for the precedingt hree
It shouldb e emphasizedh,o wevert,h att hef iguresin Table 1.2 centuries (620), despite the emergence of modern
largely reflect a few low-frequency,b ut highly destructive volcanologiyn the 20thc entury.
events.F or examplet,h et hreev olcanicc atastropheins 1902i n 2) In the 20th century, the incidenceo f deathsc ausedb y
theC aribbean-CentrAalm ericar egiona ndt heN ovember1 985 indirecth azards( e.g., post-eruptions tarvation,t sunami;
eruptiona t Nevadod el Rufz (Colombia)a ccountf or about7 5 see CHAPTER 2) has been significantlyr educed. This
percenot f thed eathsfr omv olcanica ctivityi n the2 0thc entury. reductionin part reflectst he developmenot f rapid global
Short Courses in Geology Volcanic Hazards Vol. 1
INTRODUCYION AND OVERVIEW
GO VERNMENT BODIES CONTINQENC Y PLANS
DECISION MAKERS DISASTER WARNING
POLICYM AKERS DISASTERP REPAREDNESS
RESPONDING
A QENCIES LAND-USE PLANNING
SCIENTIFIC - / ERUPTIXO N HZARDW ARNING
COMMUNITY/ FORECA'S(cid:127)k T INEGD UCAOTIFOT HNE
,/'AWARENESS- (cid:127), PUBLIC, MEDIA, AND
RESPONSIBLE /PROMOTIONP ROGRAMX DECISIONM AKERS
AGENCY / HZARDS-ZONATI'O(cid:127) N
// MAPS' (cid:127) VOLCANO
/ / / I X N
Fig. 1.3. Diagramil lustratingth ata ne ffectivep rogramto mitigatev olcanich azardsa ndr iskm ustb e builto n
a strongfo undationo f long-termb asics tudies.T he apexi s separatefdr omr esto f trianglet o indicatet he
divisiono f primaryr esponsibilitbye tweent he scientistasn dc ivil authoritiesM. odifiedf rom Tilling and
Bailey (1985, Fig. 1).
communicationsq,u ick-responsree lief-deliverys ystems, eruptiveb ehavior,b etteru nderstandinpgr esentb ehaviora, nd,
and an effective internationalt sunamiw arning network. by extrapolationp, redictingp ossiblef utureb ehavioro f the
Equally if not more important, no large, near-source volcano. Specifically, a comprehensiveu nderstandingo f
destructivet sunamih ave been generatedb y eruptionsin eruptivep henomenaan de ruptionfr equenciys thes tartingp oint
thisc entury. for mitigationo f volcanich azardsa ndr isk.
3) Deathsc ausedb y somed irect hazardsi nvolving flowage An effectivep rogramt o mitigatet her isk from volcanica nd
processes( e.g., pyroclastic flows, debris avalanches, related hazardsm ust includet he following components1: )
mudflowss; eeC HAPTER 2) havei ncreaseddr amaticalliyn identificationo f high-riskv olcanoes;2 ) hazardsa ssessment
the 20th century,l argelyr eflectingt he disastrouism pacto f andz onation3; ) volcanom onitoringa nde ruptionf orecasting;
only two catastrophe(sM ont Pel6e, 1902; and Nevadod el and4 ) volcanice mergencym anagementT. heset opicsa re the
Rufz, 1985). prime focuso f subsequencth aptersb, ut somei ntroductory
Somep ossiblee xplanationsfo r the aboveo bservationasr e remarksl,a rgelyd rawnf romT illing (1989, in press)a, reg iven
discussed later. below.
Mitigationo f Hazardsa ndR educingV olcanicR isk
Identificationo f High-riskV olcanoes
Volcanic-hazards studies must be built on a strong
foundationo f fundamentarle searcho n volcanoes(F igure1 .3), Of the some 600 active or potentially active volcanoes
including the well-integrated geologic and geophysical knowni n ihew orld,o nlya smallf ractiono f themh aveb een,
mapping, petrologic and geochemicalc haracterizationo f or are being,s tudiedin any detail. The problemi s simplya
eruptivep roducts,a nd the dating of stratigraphicallyw ell- matter of too many volcanoes, too few scientistsa nd
controlled samples. Such studies must be carried out equipmenta, nd too little moneyt o studya nd monitort hem.
systematicallyi n a long-term program--ideallyb efore the While thisp roblemp laguese vent hed evelopedco untries(e .g.,
volcanoese xhibit any signso f unrest;t hey cannotb e done France,I celand,I taly, Japan,a nd the United States),i t is
underr ushedc ircumstanceins 'theh igh-anxieteyn vironment especially serious for the developing countries (e.g.,
thatp revailsd uringa volcanice mergencyT. he resultso f these Indonesia,P hilippines,t hosei n Latin America). Thus, by
long-termb asics tudiesp rovide the basisf or decipheringp ast necessityi,d entificationo f high-riskv olcanoesis requiredt o
