Heimaey Volcano

8/18/2019 Heimaey Volcano

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Man Against Volcano:The Eruption on Heimaey,Vestmannaeyjar, Iceland


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Cover photograph: View looking southeast along streets covered by tephra (volcanic ash) inVestmannaeyjar: Eldfell volcano (in background) is erupting and fountaining lava.

View of Heimaey before the eruption: Town of Vestmannaeyjar with Helgafell in the right back-ground (photo courtesy of Sólarlma).


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Preface

The U.S. Geological Survey carries out scientic studies in the geological,hydrological, and cartographic sciences generally within the 50 States and itsterritories or trusteeships, but also in cooperation with scientic organizations inmany foreign countries for the investigation of unusual earth sciences phenome-na throughout the world. In 1983, the U.S. Geological Survey had 57 active sci-entic exchange agreements with 24 foreign countries, and 47 scienticexchange agreements were pending with 30 foreign countries.

The following material discusses the impact of the 1973 volcanic eruption of Eldfell on the shing port of Vestmannaeyjar on the island of Heimaey,Vestmannaeyjar, Iceland. Before the eruption was over, approximately one-thirdof the town of Vestmannaeyjar had been obliterated, but, more importantly, the

potential damage probably was reduced by the spraying of seawater onto theadvancing lava ows, causing them to be slowed, stopped, or diverted from theundamaged portion of the town.

The Survey was interested in the course of the Heimaey eruption because of the possibility that the procedures used to control owing lava and to reduce thedamage to a modern town may some day be useful in Hawaii and possibly evenin the continental United States.

This publication is based on observations by the authors, both with the US.Geological Survey, as well as on information from the Icelandic Ministry forForeign Affairs, Icelandic scientists’ reports through the Center for Short-LivedPhenomena, other published scientic reports, and articles in popular publica-

tions.A number of Icelandic scientists studied the scientic aspects of the eruption.The engineering aspects of the control of lava ows were studied particularly byProfessors Thorbjörn Sigurgeirsson and Thorleifur Einarsson of the Universityof Iceland's Science Institute. Also, during 1973, and in subsequent years, Ice-landic ofcials provided support to the authors for this and other volcanologicalstudies. In 1982, the U.S. Geological Survey and the National Research Councilof Iceland signed a formal agreement (MOU-IC-1) for the exchange of scienticinformation in the geosciences, to facilitate exchange of scientic personnel,and to provide a mechanism for cooperation on scientic subjects of mutualinterest, such as volcanology, seismology, geothermal studies, glaciology, and

remote sensing.


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IntroductionOne of the most destructive vol-

canic eruptions in the history of Ice-land began in the early morning of January 23, 1973, near the Nation'spremier shing port, the town of Vestmannaeyjar (Vést-mun- ayar), onHeimaey (Háme-a-ay), the onlyinhabited isle in the Vestmannaeyjarvolcanic archipelago.

Both the shing port and the groupof volcanic islands have the samename—Vestmannaeyjar. In English,Vestmannaeyjar means Westmans’Islands. In Viking times, the Nordicpeoples referred to the Irish and otherCeltic men as "West" men. Traditionsays that the group of volcanicislands, which includes Heimaey andSurtsey, got their name Vestmann-

aeyjar from escaped Irish (or Celtic)thralls who ed there after killing Hjör-leifur Hródmarsson, sworn brother of Ingólfur Arnarson, the rst person topermanently settle in Iceland.

The effusive January 23, 1973, erup-tion was the fth in a sequence of 16volcanic eruptions which have occurredin Iceland during the past 36 years.Between 1973 and mid-1983, forexample, there have been 11 additionaleruptions in Iceland, including 4 in1980, 3 in 1981, and 1 in 1983. Twoeruptions have occurred at Hekla in1980 and 1981; 8 eruptions have takenplace in the Kraa area of northern Ice-

land, where an active rifting episode(active spreading apart of the Earth'scrust along the mid-ocean boundarybetween two crustal plates) began inlate 1975 and still continues; and, in


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late May 1983, a subglacial eruptionbegan in the southwestern part of the

Grimsvötn caldera which is situatedin the western part of Vatnajökull,Iceland's largest glacier. The 1973eruption on Heimaey was also thesecond major eruption (the otherbeing Surtsey) denitely known tohave occurred in Vestmannaeyjarsince the settlement of Iceland in theninth century, although there is evi-dence of a submarine eruption in thearchipelago in September 1896. At

Oblique aerial view looking north-northwestwards of the island of Heimaey, Vestmannaeyjar,Iceland, in August 1966, showing the shing town of Vestmannaeyjar, the east-west-trendingharbor in the background, and the extinct volcano Helgafell rising to 741 ft in the right centerof the island. On January 23, 1973, lava began to pour from a 0.9-mi north-northwest-trendingssure to the east (right) of Helgafell. Eldfell eventually grew to be similar in height to Hel-gafell, 0.6 mi to the northeast.

least 13 offshore (14 includingHeimaey) and approximately 125

onshore eruptions have been docu-mented since Iceland's settlement inabout A.D. 874. Ten of the 13 off-shore eruptions occurred along thesubmarine Reykjanes Ridge, anextension of the Reykjanes peninsula.This Ridge lies along a parallel frac-ture system approximately 110 mileswest of the northeast-southwest-trending Vestmannaeyjar.

Except for the main island of


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Heimaey, all the islets in the archi-pelago are composed of Holocene

(geologically recent; that is, less than10,000 years old) basalts, and, exceptfor Surtsey, the islets are bounded byhigh sea cliffs and extend out of thesea as a series of stacks. Surtsey has asandy point to the north and a narrowboulder and cobble beach fringing therest of the island, including the steeplava cliffs on its windward side andindurated (hard and compacted) tuff on the west. Rocks of Pleistocene age(the span of geologic time from about

3 million to 10,000 years ago) cropout on the north and south parts of the island of Heimaey. These areoverlain by younger Holocene basaltows capped by a prominent volcano,

Helgafell, which last erupted 5,000years ago.

The Vestmannaeyjar islands par-allel the structural trend of tectonicssures (gjár), grabens, and craterrows on the mainland to the north inthe eastern volcanic zone. This is azone of historically active volcanoes,including Hekla, Katla, and thefamous Laki ssure eruption of 1783.

The Laki eruption derives its namefrom a mountain (Laki) which wassplit by a ssure from which a largevolume of lava and gas emanated. InIceland, the eruption is referred to asSkaftáreldar; the crater row whichformed along the ssure is calledLakagígar, and the multiple lavaows are collectively known asSkaftáreldahraun.

The Laki eruption produced thelargest lava ow on Earth observedin historic times, 2.9 cubic miles of lava which inundated 218 squaremiles. According to Prófessor Sig-

urgeirsson, the Reverend Jón Stein-grímsson, an Icelandic minister whoobserved the Laki eruption, wasprobably the rst to describe theeffect of water on the ow of lava.During 1983, in commemoration of the 200th anniversary of this awe-some eruption, a new map of Skaftáreldahraun and several bookswill be published by Icelandic scien-tists, including a historical review of Skaftáreldar by the late Prófessor

Sigurdur Thorarinsson, one of his lastresearch efforts completed just priorto his unexpected death on February9, 1983, at the age of 71.


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Left—Index map of Vestmann-aeyjar (modied from Tho-

rarinsson, 1964, and Iceland Geodetic Survey) .

Below—The island of Heimaey,with the original shorelineshown as a solid line (Geodetic Institute, Copenhagen) , theeruptive ssure of January 23,1973, a dashed line, and limitsof the lava ows of January 28and April 30, and late March1973.


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sure vent. Within 2 days a cinder-spat-ter cone rose more than 110 yardsabove sea level and was later namedEldfell or "re mountain" by the ofcialIcelandic place name committee. Theoutput of lava and tephra (a collectiveterm for fragmental volcanic materialsinitially airborne, such as ash andbombs) was estimated to be about 130cubic yards per second. Within a fewdays after the eruption, strong easterlywinds resulted in a major fall of tephraon the town of Vestmannaeyjar, com-pletely burying homes close to Eldfell.

By early February the tephra fall slack-ened markedly, but a massive lava owapproached the eastern edge of thetown and threatened to ll in the harborof Iceland's most important shing port.

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Course of the EruptionThe 1973 eruption began just

before 2 a.m., January 23, on theeastern side of Heimaey, approxi-mately 1,100 yards from the center of town. A north-northeast-trending s-sure rapidly opened to a length of about 1.25 miles, traversing theisland from one shore to the other.Spectacular continuous lava foun-tains (curtain of re) played in theinitial phase of the eruption, but theactivity soon consolidated to a small

area along the ssure about one-half mile northeast of Helgafell. Also dur-ing the rst 3 days, submarine vol-canic activity occurred just offshoreat the north and south ends of the s-

Daily movement of lava into Vestmannaeyjar inlate March 1973. Cooling operations nallyhalted the ow against the sh-processingplants shown on pages 12 and 13. Light linesshow former roads of the town under the lavaeld (modied from Jónsson and Matthíasson,1974).

View on July 23, 1973, looking northtoward a house engulfed by the March lavaow on the eastern part of Vestmannaeyjar.


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Also in early February submarineactivity just north of the ssure sev-

ered an electric power cable and awater pipeline which supplied electri-cal power and water from the Ice-landic mainland.

Icelandic geologists and geo-physicists monitored the volcano con-tinuously, both from the air and theground. Frequent aerial photographswere taken by the Iceland GeodeticSurvey. Foreign scientists also madeshort-term observations. Satellitestudies and imagery of the eruption

were acquired by both the NOAA-2and the Landsat-1 satellites. Posterup-tion aerial photographic and thermo-graphic surveys were carried outunder a cooperative study by the U.S.Geological Survey and the Univer-sity of Iceland Science Institute inassociation with the Icelandic Nation-al Research Council.

By the end of February the cin-der-spatter cone was more than 200yards high. The central crater of Eld-fell fed a massive blocky (aa lava)ow which moved slowly but relent-lessly toward the north, northeast,and east. By early May this ow was10 to 23 yards high at its front, aver-aged more than 40 yards thick, andwas as much as 110 yards thick inplaces. Its upper surface was litteredwith scoria (cinderlike fragments of dark cellular lava) and volcanicbombs, as well as large blocks fromthe main cone which broke off andwere carried along with the ow. Thelargest block soon was dubbed"Flakkarinn" (The Wanderer). Someof these blocks of welded scoria were

(Top right.)Eruption of Eldfell volcano as viewed from theNOAA-2 weather satellite, 33 hours after theeruption began. The plume extends 37 midownwind to the east, away from the town of Vestmannaeyjar. This thermal infrared imagealso shows the "hot" area of lava ows at thebase of the plume (National Environmental Satellite Data and Information Service, NOAA).

(Bottom right.)View on July 23, 1973, southeast across

homes partially buried by tephra. Vapor-shrouded Eldfell looms in the distance. Pipeswhich conveyed sea water to the lava owscross the tephra in the middle ground. Gasesrise from the tephra behind the telephonepole.

about 200 yards square and stood 20yards above the general lava surface

and were rafted more than 1,000 yards.Measurements made from a series of aerial photographs taken from the endof March to the end of April indicatedthat the lava was owing as a unitabout 1,000 yards long by 1,000 yardswide with an average speed of 3 to 9yards per day.

As the ow advanced to the northand east, large blocks slumped from thecone on February 19 and 20 and movedtoward the southeastern part of town.Also, in late March a second large lavaow moved northwest on the west sideof the main ow and covered manyhouses and the town powerplant.

By February 8, lava ejectiondropped from about 130 cubic yardsper second to 80 cubic yards per sec-ond; by the middle of March to 13cubic yards per second; and by the mid-dle of April to about 7 cubic yards persecond. As noted before, easterly windsblew tephra over the town during theearly stages of the eruption. By January


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View on July 23, 1973, north across homes partially buried by tephra in the eastern part of Vestmannaeyjar. The lava ows loom in the background. Gases that are moving through thetephra rise from the house on the right. The houses were eventually exhumed and restored.

29, the thickness of tephra variedfrom less than 1 yard in the northwest

part of town to more than 5 yards inthe southeast part.The eruption stopped in early July

1973; owing lava was no longer vis-ible, although hidden subsurface owmay have continued for awhile. Earli-er, on May 26, for example, short-lived submarine activity was discov-ered by a shing boat captain about 4miles northeast of Heimaey only 1mile from the Icelandic mainland.According to preliminary estimates

about 300 million cubic yards of lavaand 26 million cubic yards of tephrawere deposited on and adjacent toHeimaey.

Studies of the volcano's eruptiveproducts by a number of Icelandic

scientists have shown that, as the erup-tion progressed, the composition of the

material changed until it became simi-lar in composition to the lava makingup the island of Surtsey. This composi-tional change implies that the lavaprobably came from a zoned magmachamber enriched in alkalies and silicain its upper part. The chemical changesin the lava were accompanied by min-eralogic changes as well as temperaturechanges. The temperature of the lavaalso varied from 1,885° to 1,930°F(1,030°-1,055°C) during the rst week

of the eruption and increased later to asmuch as 1,975°F (1,080°C).Volcanic gases of widely varying

composition were collected from sever-al locations, showing that processes of gas fractionation operate effectively


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over short distances. Gases collectedat sea along the submerged part of the

active eruptive ssure were domi-nantly carbon dioxide. Gases collect-ed at sea bubbling up from coolingsubmerged lava ows were found tobe about 70 percent hydrogen.

Poisonous gas accumulated in lowareas within the eastern part of Vestmannaeyjar and particularly wasconcentrated in houses partiallyburied by tephra. The gas contained98 percent carbon dioxide and somecarbon monoxide and methane. The

gas had a subtle, somewhat sour odor.One fatality resulted from breathinggas within a building, and severalother people were partially overcomeby the gas.

The origin of the carbon dioxide isa matter of some conjecture amonggeologists familiar with its occur-rence on Heimaey. Perhaps it separat-ed from the other volcanic gases(chiey water and sulfur dioxide) atthe volcano's vent, owed downhill tothe town, and collected in low areas.Carbon dioxide concentrations alsohave been associated with eruptionsfrom Iceland's best known volcano,Hekla; sheep have been foundasphyxiated in small dales.

Another more likely possibility isthat the volcanic gas moved up andoutward from deeper within the vol-canic conduit through older volcanicrocks directly into the town. Othergases were removed through conden-sation or reaction, and the travel pathwas such that carbon dioxideremained the dominant residual gas.A sizable tephra wall was constructed

by bulldozers between the vent andtown to divert the gas; a long trench

was also excavated to permit the es-cape of steam. Neither barrier was com-pletely effective.

Destruction Caused by theEruption

The prolonged destruction related tothe course of the eruption was twofold:the highly visible destruction of homes,public buildings and installations, com-mercial properties, and partial inllingof the harbor by tephra falls and lavaows; and the economic and socialimpact on the residents of Vestmann-aeyjar, local commerce, and the nation-al and international economy of Ice-land.

Within 6 hours after the eruptionbegan, nearly all of Heimaey's 5,300residents had been evacuated safely tothe mainland. This rapid evacuationwas accomplished through the foresightof the Icelandic State Civil DefenseOrganization, which had a contingencyevacuation plan ready for just such adisaster. The shing eet in port expe-dited the evacuation.

Homes and farmsteads close to therift were soon destroyed by tephra bur-ial or by re from lava bombs andows. The heavy tephra fall causedsevere property damage a few daysafter the onset of the eruption. Numer-ous homes were completely buried bytephra, set are by glowing lava bombs,

or overridden by the advancing front of lava ows. Although many structurescollapsed from the weight of the tephra,dozens were saved by crews of volun-teers who cleared the roofs of accumu-


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View on July 23, 1973, southeast from dock area in the northern part of Vestmannaeyjartoward edge of lava ow where it stopped against and between two sh-factory buildings.Two boys can be seen in the right background sweeping up the tephra. By July 1974 the lavahad been completely removed and restoration of the factories had begun.

lated tephra and tacked corrugatediron "shutters" over the windows.

By early February the lava hadbegun to narrow the harbor entrance,a situation which threatened thefuture use of Vestmannaeyjar as Ice-land's prime shing port. The harboron Heimaey is the best along theentire south coast of Iceland and islocated in the midst of some of therichest shing grounds in the NorthAtlantic.

In late March, a new surge of lavainto the eastern edge of the town

destroyed a large sh-freezing plant,damaged two others, and destroyedthe local power-generating facilityand a great number of homes. Byearly May, some 300 buildings hadbeen engulfed by lava ows or guttedby re, and another 60 to 70 homes

had been buried completely by tephra.The economic and social conse-

quences of the eruption will be felt formany years. The initial social impactwas in the total upheaval of a 1,000-year-old island community. A proudand industrious people, with manyclose bonds of family and friendship,had been uprooted involuntarily, andtheir livelihoods altered in most cases.Short-term and long-term costs totaledmany tens of millions of dollars, a verylarge amount when compared with Ice-land's 1971 gross national product

(GNP) of $500 million. The locationand housing and other services for5,300 people, for example, was equiva-lent in national impact to nding emer-gency housing with overnight notice for5.3 million Americans.


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View on July 7, 1974, southeast from dock area in the northern part of Vestmannaeyjar afterremoval of lava ow which had stopped against and between two sh-factory buildings.

Control of the Lava FlowsIcelanders, from the time of set-

tlement to the present day, have hadto contend with the consequences of natural disasters: volcanic eruptions,glacier outburst oods (jökulhlaups),earthquakes, advances of outlet glaci-ers, and periods of climatic change(usually caused by the presence of sea ice off the north and east coasts).All Iceland, either directly or indi-rectly, pitched in to lessen the burdenon the residents of Heimaey.

Of great interest was the decisionby ofcials, on the advice of Ice-landic geologists and geophysicists,to "ght" the lava ows. Drawing oneld observations made on Surtsey,together with theoretical calculationson the cooling effect of water on

molten lava, and on small experi-ments conducted on Surtsey and later

on Heimaey at the beginning of theeruption, several Icelandic scientistsrecommended that cooling and hard-ening of lava by spraying of seawaterbe used to try to impede or stop theow of lava on Heimaey. This effortultimately became the most ambitiousprogram ever attempted by man tocontrol volcanic activity and to mini-mize the damage caused by a vol-canic eruption. Consequently, it wasan experiment of importance to other

communities threatened by damagefrom volcanoes.Advance of the main lava ow to

the north initially threatened to closethe entrance to Vestmannaeyjar har-bor. Likewise, advance of the ow tothe northwest threatened the town


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A panoramic view east-southeast across the shing port of Vestmannaeyjar on May 5, 1973.Dark, tephra-covered ground is apparent, with lava ows into the town and harbor in the leftbackground.

View to the south from Vestmannaeyjar's outer harbor on May 4, 1975. Seawater is beingsprayed directly onto the lava ow front to arrest inlling of the harbor entrance.


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proper and the many sh-processingfactories. Accordingly, a twofold pro-gram was begun in late February: lavacooling by spraying to increase thelava's viscosity and cause it to slowand thicken, and construction of a lavabarrier on the ow's northwest marginto prevent its advance into the town.

A limited cooling operation wasrst begun on February 6, just 15 daysafter the eruption began. This use of the city water supply indicated thatspraying water on the ow slowed itsadvance and caused the ow front tothicken and solidify. In early March apump ship that could deliver a largevolume of water was brought into theharbor. In late March and early April,large-capacity pumps were leasedfrom the United States and were usedto deliver water to the ow front andto selected sites on the surface of theow.

In early April, pumps situated inthe harbor were delivering sea-waterup to 1.3 cubic yards per second tovarious parts of the ow. Practically

all this water was turned into steam. Itcooled about 70 percent of its volume

of lava to 212°F (100°C), substantiallybelow the solidication point of basalt.The basalt is quite uid at 1,800° to2,200° (1,000°-1,200°C) and essential-ly ceases to ow by the time it cools to1,500°F (800°C).

Water was pumped directly on theow front at sea level and also waspumped through a number of primaryplastic pipes. Each main pipe branchedinto a series of smaller pipes. In addi-tion, a large steel pipe was used. More

than 19 miles of pipe (75 percent plas-tic) and 43 pumps were eventually em-ployed in the cooling program.

The most difcult aspect of the cool-ing program was to deliver large vol-umes of seawater to the surface of theow far behind the ow front. Thewater effectively increased the viscosi-ty, thereby producing internal lava bar-riers and causing the ow to thickenand ride up over itself.

First, the margin and surface of theow were cooled with a battery of re-hoses. Then a bulldozer track wasmade up the side of the slow movingow. The water produced large vol-umes of steam which markedly reducedvisibility and made road building dif-cult. Then the larger plastic pipes weresnaked up onto the ow; they did notmelt from the heat as long as waterowed through them. Small holes inthe pipes also helped to cool hot spots.The discharge pipes were mostly 8inches or 10 inches in diameter, deliv-ering 13 or 26 gallons of water per sec-ond in one spot on the lava surface.From there the steaming water would


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Part of northeastern Heimaey and the east-ern part of Vestmannaeyjar showing deploy-ment of pipes along northwestern edge of

new lava ows on April 15, 1973, and accessroads (dashed lines) bulldozed onto andthrough the lava eld. Intake pumps arepositioned along two harbor piers (modied from Jónsson and Matthíasson, 1974) .

gradually spread out. At the higherowrate up to 3 acres of lava wereengulfed in dense steam. At eachpoint water was poured on for about2 weeks, until steaming near thepoint of discharge had decreasedmarkedly. By then the lava ow hadcooled to the boiling point of waterto a depth of 10-15 yards.

Cooling of the ow margin was

used in conjunction with bulldozeddiversion barriers of scoria adjacent to

the ow margin. The marginally cooledow tended to pile up against the barri-er rather than to burrow under it aswould be the case if the ow weremore uid.

The water-cooling program pro-duced a noticeable effect on the mainlava ow. The lava was distinctivelychanged where water had been pouredon it. Before watering, the ow surfacewas blocky and covered with partlywelded scoria and volcanic bombs and

had a distinct reddish, oxidized color.The general surface had a local relief of 1 yard or less, which was the generaldimension of many of the blocks. Largemasses of welded scoria which had bro-ken off from the main cone, however,stood 10 to 20 yards above the owsurface. After watering, the generalow surface became much more jaggedand had a local relief of up to 5 yardsand was much more difcult to walkon. Cooling had apparently caused themore plastic interior of the ow tobreak upward and ride over itself.

The ow surface turned black togray. In places closely spaced jointsperpendicular to larger joints and shearswere similar to the joints in pillowbasalts. Elsewhere, white incrustationsof salt coated fractures that were for-merly deeper in the ows, where thecooling seawater was heated and evap-orated. The change in surface textureand color can be noted readily on coloraerial photographs.

From February 6, 1973, until thelava cooling operation ended on July10, 1973, approximately 8 million


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cubic yards of seawater were pumpedonto the lava ows, converting about 5

million cubic yards of molten lava intosolid rock. At the peak of the lava cool-ing, in early April 1973, 75 men wereemployed around the clock.

Like all volcanic eruptions, theHeimaey eruption was a special case,and the methods employed to controlthe lava ows were especially suited tolocal conditions. First, the initial erup-tive ssure was only 1,100 yards fromthe center of a large town with an adja-cent and economically important har-

bor, and consequently it was in thenational interest to attempt to minimizedamage. Secondly, the main lava owwas viscous and slow moving, allowingtime to plan and carry out the controlprograms. Thirdly, seawater was read-

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On May 4, 1973, workmen laid additionalpipes to carry seawater up onto the lavaow front and tephra bulwark to cool andharden the still-owing lava behind thechilled lava margin.

Area around eastern Vestmannaeyjar show-ing the parts of the new lava eld that werecooled over different periods of time andthe amount of seawater pumped. Heatextraction areas also shown (modied from Jónsson and Matthíasson, 1974) .


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Vertical aerial photograph taken on August 4, 1960, of the island of Heimaey, Vestmannaeyjar,Iceland, showing the shing port of Vestmannaeyjar, the crater of Helgafell volcano, and thesingle airstrip. (photo by U. S. Air Force).


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Vertical aerial photograph taken on September 8, 1973, of the island of Heimaey, Vestmann-aeyjar, Iceland, showing the shing port of Vestmannaeyjar, the craters of Helgafell and Eld-fell volcanoes, the double airstrip, and the new land on the east (Iceland Geodetic Survey) .


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ily available in the nearby harbor.And fourthly, transport by sea as

well as by a local road system wasgood, and it was relatively easy tomove in pumps, pipe, and heavyconstruction equipment. Neverthe-less, it is likely that some of thelessons learned from the Heimaeyexperience can be adapted to erup-tions in other places.

Scientists and planning authori-ties also had the benet at Heimaeyof detailed topographic maps rapid-ly produced from vertical aerialphotographs. These maps, in con-nection with geodetic surveys, per-mitted measurement of the rate of movement of the main lava owand an assessment of the bestplaces to build lava diversion barri-ers. They also were critical in plan-ning for administrative, engineer-ing, and scientic purposes.

The water cooling and construc-tion of lava barriers denitely havehad a marked effect on the charac-ter and course of the lava ows onHeimaey. From boreholes drilledinto various parts of the lava eldnorth of Eldfell, temperature meas-urements indicated that the lavacooled 50 to 100 times more rapid-ly in areas sprayed with seawaterthan in areas of self-cooling. Theplacement and measurement of movement of markers (from groundsurveys and aerial photographs) onthe lava eld substantiate the effectof cooling on the speed of lavaow. It has been established clear-ly that the work on Heimaey repre-sented the greatest effort ever

attempted to control lava ows duringthe course of an eruption; the total esti-

mated cost for the lava cooling opera-tions (labor, equipment, transportation,fuel, and others) was $1.5 million.

Extraction of Heat FromCooling Lava Flows

Scientists and engineers from theUniversity of Iceland, residents of Heimaey, and an Icelandic engineeringrm, Verkfraedistofa Gudmundar ogKristjáns, teamed up to create a district-heating system for the town of Vestmannaeyjar using the thermal ener-gy from the cooling lava ows. Initialfeasibility studies on the eastern part of the new lavas indicated that about 5yards of scoria (tephra) lay on top of about 100 yards of new lava, all of which was resting on the former seabottom. It was also determined thatmolten lava was slowly cooling inwardfrom the top and bottom of new lavas,but that the thermal energy from thismolten lava could be used to providespace heating to the town of Vestmann-aeyjar.

By early 1974, heating experimentshad proven successful, and the rsthouse was connected to a prototypesystem. Additional experiments wereconducted during the next 5 years, andmore houses and the hospital werehooked up to the heating system. By

Vertical aerial thermograph taken on August20, 1973, at 2233 hrs UT of the island of Heimaey, Vestmannaeyjar, Iceland, showingthe thermal emission from joints and ssuresin the cooling lava ows (compare with theSeptember 8, 1973, aerial photograph on p.19)(courtesy of NASA) .


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Cutaway schematic diagram of the subsurface emplacement of concrete pipes above the cool-ing lava and connection to the heat exchanger on the surface to provide a source of heat for adistrict-heating system for the town of Vestmannaeyjar. (Modied from Björnsson, 1980, by permission of the author and the publisher, Atlantica and Iceland Review).


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Schematic plan view of one of four square areas (110 yd x 110 yd) lava eld on Heimaey,where heat is extracted from cooling lavas at depth. Each one-fourth of this square area (55yd x 55 yd) can generate 5 megawatts (MW) of hot water at peak load (or 2.5 MW at normalload). (From information provided by Próf. Sveinbjörn Björnsson, University of Iceland) .

late 1979, with the design for a heat-ing system based on cooling lavaexperimentally proven, a major engi-neering effort got underway to devel-op 4 areas, each 110 yd x 110 ydsquare, in the eastern part of the new

lavas. Each area was designed so thatthe xed facilities (pumping stationsand heat exchangers) were centrallylocated. Each quarter section, 55 yd x

55 yd square, during operation containsa matrix of nine steamwells spaced at18.5 yd intervals and is capable of pro-ducing 5 megawatts (MW) of peakpower or 2.5 MW at normal operation.The steamwells are constructed in the

unconsolidated tephra deposits, and aseries of short concrete pipes are laidhorizontally, one on top of the other, ina branching fashion to collect the steam.


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An overlying network of pipes

sprays water onto the area surround-ing the steamwells. The water perco-lates downward until it encounters thecooling lava where it is converted to

steam. The steam rises vertically where

it is collected by the steamwells andmoves through pipes to the heatexchangers, which heat up water circu-lating through the central heating sys-

Isometric diagram of layout of the 5 MW pipingsystem to and from the cooling lava eld, heatexchangers, and to and from the town pumping

system. (From information provided by Próf.Sveinbjörn Björnsson, University of Iceland,and from the information booklet, “Fjarhitun Vestmanneyja-Upplysingar um Veituna,” 20 March 1982, 5 p. (In Icelandic)).


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tem of the town. Water at a tempera-ture of 176°F is supplied to the townpumping station; 95°F water isreturned from the town pumping sta-tion.

By early 1982, the district heating

system had been connected to nearlyevery home on Heimaey. According toDr. Sveinbjörn Björnsson, Professor of Geophysics at the University of Ice-


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land, the volcanic heat is projected tolast about 10 years (an estimated 2.5

years for each of the four 110 yd x110 yd areas), after which a return toother energy sources will be neces-sary. Of practical importance to theUnited States and to other countries,however, is that the lessons learnedby the Icelanders, in directly tappingheat from cooling lava, can beapplied to other areas of active vol-canism.

ConclusionEven after all the devastation and

disruption of lives and livelihood, thevolcanic eruption had some peripher-al benets. On the plus side, the lavaand tephra added nearly a square mileto the preeruption area of Heimaey,increasing the island's size by about20 percent. About 2 million cubicyards of tephra have been clearedaway from the town and have beenused to extend the runways on the is-

land's only aireld and as landll forthe siting of 200 new homes. Eventhe remaining heat of the volcano hasbeen tapped, an effort rst begun inJanuary 1974, only 1 year after theeruption began. The tongue of lavathat almost blocked the harborentrance has also been turned into anasset and is now acting as a breakwa-ter, helping to protect the harbor fromstorms.

Another aspect of the recoveryeffort was the enormous cleanup andrestoration effort funded by all Ice-landers through a special surtax and

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by Iceland's foreign friends. Substantialeconomic help was provided by the

government and private groups andorganizations of the other Nordic coun-tries. The Danish Government was thebiggest benefactor, providing directassistance of $1,488,000. The U.S.Government provided $339,000 indirect and indirect assistance. Even thetiny Faeroe Islands contributed$97,600. The value of assistance fromall nations was about $2,100,000, withan additional $380,000 provided byinternational organizations and private

groups, such as the American-Scandi-navian Foundation. By the summer of 1974, about 2,600 residents, or aboutone-half of the population, hadreturned and plans had been developedfor the construction of an additional450 new homes. By March 1975 thepopulation had grown to 4,300 people,or 80 percent of the preeruption popu-lation. By December 1, 1982, the pop-ulation of Vestmannaeyjar had reached4,657. Vestmannaeyjar once again hasbecome a vigorous shing community,a laboratory for geologists, a majortourist attraction, and a testimony tothe perseverance and courage of theislanders to turn, with the help of otherIcelanders and foreign friends, a seem-ingly hopeless situation into a brightfuture.

The success of the islanders in theirbattle with the volcano has promptedother communities faced with volcanichazards to look to the lessons learnedon Heimaey. The worldwide interesthas contributed to making Eldfell oneof the best known volcanic eruptions in


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Selected ReadingsBjörnsson, Sveinbjörn, 1980, Natural heat saves millions of barrels of oil: Unique pro-

cedures developed by Icelanders—they even tap hot lava: Atlantica and Iceland Review, v. 18, no. 1, p. 28–37.

Einarsson, Thorleifur, 1974, The Heimaey eruption in words and pictures: Heimskringla,

Reykjavik, 56 p.Grove, Noel, 1973, Volcano overwhelms an Icelandic village: National Geographic Magazine, v. 144, no. 1, p. 40–67.

Gunnarsson, Arni, 1973, Volcano: Ordeal by re in Iceland's Vestmann Islands: IcelandReview Book Series, Iceland Review, Reykjavik, 96 p.

———1974, Life returns to the Westman Islands yet the marks of the volcanic eruptionare here to stay: Atlantica and Iceland Review , v. 12, no. 1–2, p. 33–40.

Hamar, H. J., 1976, People are back to the Westman Islands—but life will never bequite the same: Atlantica and Iceland Review , v. 14, no. 4, p. 14–20.

Jónsson, V. K., and Matthíasson, Matthías, 1974, Lava cooling on Heimaey—methodsand procedures:Tímarit VFI, v. 59, no. 5, p. 70–81, and p. 83. (In Icelandic)

Sigurgeirsson, Thorbjörn, 1974, Lava cooling: Timinn, 19 January 1974, Reykjavik, p.8–9 and p. 13. (In Icelandic)

Thorarinsson, Sigurdur, 1964, Surtsey—the new island in the North Atlantic: AlmennaBókafélagid, Reykjavik, 110 p. (In Icelandic) (Also reprinted in English by theViking Press, New York, in 1967)

———1977, The eruption ssures of the 1973 Heimaey eruption: Náttúrufraedingurinn,v. 47, no. 1, p. 1–7. (In Icelandic)

Thorarinsson, Sigurdur, Steinthórsson, Sigurdur, Einarsson, Thorleifur, Kristmannsdóttir,Hrefna, and Óskarsson, Niels, 1973, The eruption on Heimaey, Iceland: Nature, v.241, no. 5389, p. 372–375.

Movies About the 1973 Eruption on HeimaeyFire on Heimaey (Eldur i Heimaey), VÓK Film, Reykjavik, Iceland.

Days of Destruction, Iceland Film Distributors, Kvik sf. kvikmyndagerd, Reykjavik,Iceland.

The Heimaey Eruption: Iceland 1973, University of Waterloo, Department of Man-Environment Studies, Waterloo, Ontario, Canada.

Volcanoes, Exploring the Restless Earth, Encyclopedia Britannica, Educational Corpora-tion, Chicago, Illinois.

Season of Fire, MacMillan Films, Inc., Mount Vernon, New York.Volcano, IMAX Systems Corporation, Toronto, Ontario, Canada.

the world. Scientists in Iceland andaround the world will be studying the

photographs, aerial thermographs,and rock samples for years to come,looking for clues that will contributeto an understanding of the nature of

volcanoes, as well as for methods tomitigate the destructive effects of future

eruptions whether they be in Iceland, inthe United States, or in any other inhab-ited volcanic region of the world.


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Oblique aerial view in early March 1973 of Heimaey, Vestmannaeyjar, Iceland. Steam risesfrom lava-cooling operations on land and from lava entering the sea (photo by Gudmundur Sigfússon. Courtesy of Sólarlma).


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As the Nation's principal conservation agency, theDepartment of the Interior has responsibility formost of our nationally owned public lands and nat-ural resources. This includes fostering the wisestuse of our land and water resources, protecting oursh and wildlife, preserving the environmental andcultural values of our national parks and historicalplaces, and providing for the enjoyment of lifethrough outdoor recreation. The Departmentassesses our energy and mineral resources andworks to assure that their development is in the

best interests of all our people. The Department also has a major responsi-bility for American Indian reservation communities and for people who livein Island Territories under U.S. administration.

This publication is one of a series of general interest publications preparedby the U.S. Geological Survey to provide information about the earth sci-ences, natural resources, and the environment. To obtain a catalog of additional titles in the series "General Interest Publications of the U.S. Geo-logical Survey," write:

USGS Information ServicesBox 25286, Federal CenterDenver, CO 80255


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