VOL. 10 NO. 3 SEPTEMBER 1992

20 NOV 1992

Cleaning up after Cyclone Namu, Solomon Islands, 1986. Hazard mapping will help identify vulnerable areas.

REPRESENTING the Australian community SERVING the victims of disaster

CONTRIBUTING to skilled and coordinated international disaster response

AODRO NEWSLETTER 3

ASSESSMENT OF NATURAL HAZARDSIN THE SOLOMON ISLANDS AND

IMPLICATIONS FOR OTHER PACIFICISLAND COUNTRIES

i 'mural HazardsSciences,

rsity, NSW 2109

IntroductionThe emphasis in this study of natural hazards in

the Solomon Islands is on the consequences of hazardimpact with the aims of identifying the most damaginghazard, the most damaged area, the most deadlyhazard and the most deadly area. Whilst damage toall buildings and infrastructure, crops and theenvironment has been recorded, the mapping projecthas concentrated on damage to traditional buildings.The project was undertaken with a grant from theAustralian International Development AssistanceBureau (AIDAB).

The natural hazards studied include tropical cyclones,earthquakes, volcanic eruptions, tsunami, other storms,floods, and drought. The first four of these hazards havehad the greatest impact on the Solomon Islands.

The position of individual islands, in relation to tectonicplates, latitude and longitude as well as their size andtopography, determines the incidence to natural hazards.Because of these variabilities, each island and separategeographic areas within the larger islands, have to bestudied individually in order to determine theirvulnerability. In order to assess the amount of damagewithin areas of a "reasonable" size, the islands weredivided into 146 areas which generally correspond withthe wards used in the 1976 populationcensus. This approach was used as fairlyaccurate population figures, needed toassess the risk from each hazard, wereavailable for each ward.

The Solomon Islands Damage Scalewas developed in order to estimate thedegree of damage to houses constructedfrom traditional materials. The scale isconstructed in such a way thatcumulative damage to traditionalbuildings can be calculated for anynumber of hazards or type of event,thereby allowing identification of themost damaged area and the mostdamaging hazard (Blong et al., 1991).

Various sources provided the data for this project, themost valuable being the personal library of J.C Grover,ex-resident and Chief Geologist of the Solomon Islandsas well as natural disaster files maintained by the NaturalHazards Research Group at Macquarie Universitycollected from the Sydney Morning Herald and PacificIslands Monthly, The British Solomon IslandsProtectorate News Sheet, the British Solomon IslandsReports for the Year, Solomon Islands newspapers, andmissionary magazines.

Physical and SocialSettingThe Solomon Islands consists of almost 1,000

geologically diverse islands which cover 27,990 kmwithin 800,000 km of ocean. They are located between5° and 12° south and 155° and 170° east, which placesthem on the northwestern boundary of one of the mostactive cyclone regions in the world (Figure 1).

The main group of six islands form a southeast trendingdouble chain of islands which vary in length from 80to 170 km and 25 to 50 km in width. It is situated ina complex tectonic zone at the boundary of the Pacificand Indo-Australian plates (Cooper et al., 1986). Theseislands are of volcanic origin overlain by marinesediments and are covered with dense rain forest in themountainous interior. Guadalcanal, which contains 18%of the population, has a mountainous interior containingthe miles! peak in the islands al 2447 m. These mountainsare characterised by sleep sided valleys prone to

Figure 1 Solomon Islands

4 AODRO NEWSLETTER

landslides and short rivers prone to flash floods. Thesouthern "Weather" coast of Guadalcanal is so calledbecause of the high rainfall and stormy seas experiencedin the area.

The Guadalcanal Plains along the northeast coast ofthe island, 47 km long and oip to 10 km wide, is thelargest alluvial area and contains the largest agriculturalarea in the country. Henderson International Airport, issituated on these plains as is a small industrial base andsome plantations. The largest town and major businesscentre in the islands is Honiara which has a populationof about 30,000 (10% of the total Solomon Islandspopulation) and is situated on the western border of theGuadalcanal Plains.

Malaita is the most populated island containing 28%of the population. Eight percent of the population inhabitsMakira most of whom live on the north coast away fromthe swampy highlands. New Georgia (8% population)is a group of islands with a fringing reef. The majorityof the population live on the coast. Choiseul (5%population) is the least developed of the main islands.Apart from two highland villages, the entire populationare coastal dwellers. Isabel contains 5% of the totalpopulation; three quarters of these live in the south eastof the island. Thirteen kilometres north of Guadalcanallies the small, fertile, and thus densely populated, activevolcanic island of Savo.

Ontong Java Atoll, on the Ontong Java Plateau, lies270 km to the north of Isabel, between the latitudes5°-5.6° South (Figure 1). The atoll consists of 120vegetated islands of which two are permanentlypopulated; many of the other islands are used as vegetablegardens. The total land area is only 12 km2, the widestpiece of land is 1 km and the highest area is a taromound only eight metres above sea level.

Temotu Province is geologically separated from the mainislands as it is situated on the North New Hebrides Arc.It lies approximately 450 km to the southeast andcomprises nine single or groups of small scattered islands.Eight of the nine islands are volcanogenic, Tinakula beingthe only active volcano. The Reef Islands are biogenicin origin.

About 90% of the Solomon Islands population ofapproximately 300,000 live in rural areas and are engagedin subsistence agriculture in villages of fewer than 200people. The main form of communication in the islandsis by bush tracks and the main form of inter-islandcommunication is by boat, although most of the largerislands also have airfields.

Meteorological HazardsTropical Cyclones - Spatial and TemporalDistributionThe tropical cyclone season in the Solomon Islands is

generally considered to extend from November to April.

However Cyclone Ida occurred from 30 May - 1 June1972 and Cyclone Namu from May 16 - 19, 1986.

A total of 45 cyclones have been identified in theSolomon Islands area. The first was recorded in 1568,the second in 1788 and a total of only eight cyclonesare known to have occurred before 1900. Six cycloneswere reported in the first 50 years of this century and31 since 1950. The cyclone record is certainly incompletebefore 1950. It was not until the early 1950s that cyclonesare known to have caused considerable damage in theSolomon Islands. Of the 31 cyclones which have occurredsince 1950 at least 21 of them have caused damage.

The number of cyclone and damaging cycloneoccurrences since 1950 are listed for each island in Table1. In terms of the number of damaging cyclones,Guadalcanal has been most affected as 12 of the 16cyclones have occurred on that island.

Table 1 Cyclone occurence on individual islandssince 1950

ISLAND

GuadalcanalMakiraMalaitaIsabelChoiseulShortlandsNew GeorgiaSikaianaOntong JavaAnutaDuffSanta CruzTikopiaUtupiaVanikolo

NUMBER OFCYCLONES

16129462712117532

DAMAGINGCYCLONES

1299341412114532

Ontong Java, situated between 5°- 5.6° south, could beconsidered outside the tropical cyclone belt as cyclonesrarely form so close to the Equator, but has experiencedtwo damaging cyclones since 1950. Bayliss-Smith (1988)has suggested that the mean recurrence interval forcyclones on Ontong Java since the early 19 century is60 years. The return interval for cyclones in the SolomonIslands as a whole since 1950 is one cyclone per year.However the interval varies greatly for each island. Forexample the return interval on Guadalcanal is 2.5 years,Malaita it is four years and Tikopia it is eight years.

Despite these average recurrence intervals the frequencyof cyclones is quite variable. The 1971-1972 cycloneseason produced three cyclones which affected the maingroup of islands. Ursula (December 1971) caused damageon southern Makira. Carlotta (January 1972) affectedGuadalcanal, Makira and Malaita. Ida (May 1972)affected all six of the main islands. Similarly, between

AODRO NEWSLETTER 5

1951 and 1953, Tikopia in the Eastern Islands sufferedcyclones in December 1951, January 1952 and March1953.

Tropical Cyclone DamageCumulative cyclone damage for the 20th century

estimated using the Solomon Islands Damage Scale ismost severe on the larger islands of Guadalcanal, Malaitaand Makira (Figure 2). The more northeastern of themain islands have been less affected. The islands inTemotu Province have suffered little damage except forthe most southerly island of Tikopia (Blong et al., 1991).Undoubtedly, Cyclone Namu, 1986, was the worstcyclone in the memory of Solomon Islanders and thesocial and economic effects of that cyclone have beenwell documented. Ninety thousand people, almost onethird of the total population, were made homeless anddamage was estimated at AS25 million.

As this cyclone affected a number of islands it illustratesthe type of damage cyclones cause to various areas.Incessant rainfall for four days was the main cause ofthe damage on Guadalcanal where 22% of houses and70% of food gardens were destroyed or damaged. Floodsand landslides in central Guadalcanal washed away orburied villages, whilst flooding rivers covered parts ofthe Guadalcanal Plains with at least one metre of mudand silt. Houses, food gardens, commercial property,plantations and Henderson Airport were similarlyaffected. On the Weather coast, many villages weredamaged by wind, rain and landslides.

In Honiara high winds knocked down power andtelephone lines. Water was cut off as the water pipe wasswept away and bridges were damaged; the floodingand damage to Henderson Airport closed it for five daysbefore re-opening for emergency operations. On Malaitaand Guadalcanal, rivers brought tonnes of mud, silt andtrees into lowland areas. Storm surge damage was alsoapparent in coastal areas but difficult to distinguish from

the effects of surface runoff and riverine flooding. OnMakira, it was the wind which caused most damage toplantations and crops, particularly on the coastal areas.

On Sikaiana atoll, which has a total land area of 2 km2,80% of the houses were destroyed by wind and the watersupply from wells and tanks was contaminated by debrisand salt spray. The alternative to water, coconuts, wereall destroyed as the palms were downed in the wind.

Most of the damage to the southern islands of OntongJava during Cyclone Annie (1967) was from a stormsurge which washed over the island destroying a villageand many of the gardens and coconut trees.

Tropical Cyclone DeathsOf the 45 cyclones in the record, only 11 are known

to have caused deaths. One hundred and fifty-fourfatalities have been recorded from cyclones and 111 ofthese, that is 70%, occurred during cyclone Namu. Only24 people are known to have been killed in other cyclonesthis century, though this is probably an underestimate(Blong and Radford, in press).

Of the 154 fatalities it is possible to say how 94 occurred.Sixty-one (64%) were due to landslides during cycloneNamu. Three drowned in rivers, three were hit by fallingtrees and 23 drowned in the ocean when ships sank.

One hundred and two of the total deaths occurred onGuadalcanal, 28 in the eastern islands and 15 on Malaitaand four on Makira. One death occurred on each ofBellona, Florida and Santa Catalina. No deaths fromcyclones have been recorded from Ontong Java, Isabelor the Western Province, including the Shortland andTreasury Islands, New Georgia and Choiseul. In TemotuProvince, deaths are recorded from the Reef Islands,Utupia, Vanikolo and Nendo (Table 2).

WESTERN SOLOMON ISLANDS

Santa Isabel

' d>£3iVew Ge°'9'a0 ^l-i^X IslandsCook Volcano**/

Florida

Islands, s a n sKavachl Volcano o Russell V,? Savoe Oa,

lslandsDAMAGE FROMALL CYCLONES

ESD i| I No Dai

UM «. Three Sisters

• Santa Ana°Santa Catalina

Figure 2 Damage from cyclones derived from Solomon Islands Damage Scale

6 AODRO NEWSLETTER

Cyclone Namu dominates the record for deaths fromcyclones. Ninety-seven occurred in the highlands ofGuadalcanal where 61 people are known to have beenburied in landslides. It is possible that some of the 36deaths where the cause is not known were also the resultof landslides.

StormsThere are only nine storms in the Solomon Islands natural

hazards database. While this is almost certainly anunderestimate it is worthwhile documenting. Alldamaging storms are reported from the islands of Florida,Malaita, Ghizo, and Guadalcanal. The first storm reportedoccurred in 1888 but the first report of damage was in1936 when riverine flooding occurred. The third stormreported was nineteen years later in 1965 when a shipwas badly damaged. Between 1968 and 1984, six morestorms occurred, five of which caused wind or raindamage. All of the damage is reported from coastal areaswhere rivers flooded from excessive rain or high windsuprooted trees and disrupted power and telephoneservices.

Table 2 Place of death from cyclones

GuadalcanalMalaitaMakiraFloridaSanta CatalinaBellonaVanikolaReefNendoUtupiaunknown

Total

NUMBEFOFDEATHS

102154111205212

154

The earliest record of deaths due to a storm was in1595 when one of Mendana's exploratory shipsdisappeared off the island of Tinakula in what wasdescribed as a squall. An estimated 20 crew drowned.

Seven people drowned when a canoe sank during astorm in 1888 and in 1984 13 people drowned off thecoast of Ontong Java when their canoe capsized. It isprobable that many more similar drownings have goneunrecorded.

FloodsOnly 10 riverine floods are in the record, the first in

1961. Localised damage has been reported from six ofthe floods. A total of three children died in two floods.Damage has been reported on the island of Guadalcanalfive times, and once on each of the islands of Isabel,

Malaita, Makira and Savo. Heavy rain which causedfloods and landslides on Savo on 1964 resulted inresettlement of some villages as food gardens were badlydamaged. Food aid had to be supplied to about one quarterof the Savo population for three months.

DroughtThere are four droughts in the database, only one of

which caused famine. This occurred in between thecyclones of 1952 and 1953 on the island of Tikopia.Seventeen people died as a result of the famine. Foodrelief arrived in time to prevent further deaths.

Geologic HazardsSeismic activity in the Solomon Islands is generally

due to the underthrusting of the Solomon Sea Plate(between the Solomons and Papua New Guinea) beneaththe north western islands of the Solomons, but the tectonicsystem is complex and the distribution and intensity ofearthquakes is varied. From Bougainville to Makira thetectonic trench is well developed and seismicity is highalong the southern side of the island arc. Between Makiraand the eastern islands in Temotu Province the area isof lower seismicity.

Earthquake DamageDamage has been recorded for about half of the 60

earthquakes reported this century. The most damage fromearthquakes has occurred in the larger, most populatedislands of Malaita, Makira, Guadalcanal and Santa Isabel,with the southern parts of Guadalcanal and Makira havingthe greatest risk. No earthquakes or earthquake damagehave been recorded in Ontong Java (Figure 3) (Blonget al., 1991).

The most damaging earthquake recorded in the SolomonIslands occurred in October 1931 and had a Richtermagnitude of 8.1. Malaita and Makira sufferedextensively. On Makira, two villages were destroyed byground shaking, 18 villages were swept away by a tsunamiwhich rose 6-10 m above high tide and hundreds oflandslides buried gardens. On Malaita, landslidesdammed rivers which changed course, burst through theirbanks and flooded downstream.

The 1939 earthquake on Guadalcanal caused a tsunamiwhich was also reported to be 6-10m in some areas.This destroyed most of the houses along the north andsouth west coast of the island. On the south west coastof Isabel and in the New Georgia islands, houses andcrops were also damaged by a tsunami.

The earthquake of 21 April 1977 was 7.5 on the Richterscale. Extensive damage occurred in central Guadalcanalwhere landslides buried villages in a mountainous areawhere narrow ridges are divided by narrow and steepravines. The landslides muddied streams and deprivedvillagers of a source of water.

Damage also occurred on Isabel, Malaita and Makirabut reports indicate that it was minor. A small tsunamioccurred on the south coast of Makira but no damage

AODRO NEWSLETTER 7

was reported. In Honiara, the damage to poorlyconstructed buildings from ground shaking wasconsiderable but minimal to sound buildings. During thefive weeks following the earthquake three or fouraftershocks occurred each day causing fresh landslidesin the interior of Guadalcanal.

As vegetable gardens had been destroyed in thelandslides and floods, food was provided for 10,000people for eight months. Thirteen distribution points wereset up but at times it was not possible for some villagersto reach these areas due to continuing bad weather. Fooddrops and the evacuation of people from the south coastof Guadalcanal by ship was delayed due to heavy rainand rough seas.

Earthquake DeathsOf the 30 damaging earthquakes in the record only four

of them have caused a total of 104 deaths. Fifty-Fourof them occurred on Guadalcanal, five on Malaita and50 on Makira. Of the 78 fatalities for which the causeof death is known, 62 died in tsunami, 15 in landslidesand one was killed by a falling rock.

TsunamiTsunami may be caused by distant or local earthquakes.

Since 1952, three tsunami generated at large distanceshave been recorded in the Solomon Islands but nonehave caused serious damage or deaths. The 1960 tsunamicaused by the Chilean Earthquake did cause some damageto wharfs and inundated a village in Santa Isabel butthe damage was minimal as the houses were raised onposts. It is tsunami generated by the local earthquakesnoted above that have caused major damage and deaths.

Volcanic EruptionsThere are four active volcanoes listed in the Catalogue

of the Active Volcanoes of the World (Fisher, 1957). Theseare Savo, Kavachi, Cook and Tinakula. Damage anddeaths have been confined to Tinakula and Savo and onthe two occasions where the impact of eruptions has

been documented, it was the inability to flee the islandswhich apparently caused the majority of deaths.

In approximately 1827, a nuee ardente eruption,accompanied by an earthquake and tsunami occurred onthe island of Tinakula. The inhabitants rushed to thecoast so they could escape the effects of the eruptionby going to sea, but a tsunami made it impossible tolaunch canoes which were the only means of escape.Consequently, the entire population was killed.

In the 1840s Savo erupted and an estimated 500 peopledied. As was the case on Tinakula, the only escape routewas by sea. Reportedly, many people died as there werenot enough canoes to escape from the island.

Kavachi, a submarine volcano in the New Georgia group,was first noted to have built above sea level in 1952.During subsequent eruptions it built above sea level in1969, 1970 and 1976, but was soon eroded down tobelow sea level. In 1951 a minor tsunami occurred duringthe eruption. The Cook volcano has not built up abovesea level and its identification is questionable accordingto Exon and Johnson, (1986) who think it may be adeep water vent.

The two volcanic eruptions which occurred in the firsthalf of the 19th century caused an estimated 600 deaths,dominating the death record.

Indirect Health Effects ofHazardsThe number of indirect deaths which have occurred

following a number of the natural disasters have notbeen accounted for in this study as figures are notavailable; however, they may well exceed the numberof direct deaths.

Short/ande tt Islands

0 ^ t^\?\ Geo'9'aCook Volcano* -° "U Jslands

Kavachi VolcanoRussell

Damage Index

• 5

• 4

ED 2

m 1I | No Damage

o Sikaiana

Guadalcanal

%, Three Sisters

Santa Ana

Santa Catalma

Bellona

Figure 3 Earthquake damage 1900 - 1990 ?_

8 AODRO NEWSLETTER

Five months after Cyclone Kerry struck (1979), anoutbreak of malaria occurred, evidently because mosquitobreeding places had not been sprayed following thecyclone. Following Cyclone Namu, severe exposure toflood conditions and an outbreak of malaria and diarrhoeacaused the death of many children.

Survivors of the 1931 earthquake suffered furthercasualties as they had no shelter and an epidemic ofinfluenza and pneumonia occurred. Six months after the1977 earthquake, five children and an elderly man diedin a village to which people had been evacuated, thecause being poor sanitation.

Hazard Pairing -Exacerbation of EffectsHazards occurring together or in close temporal

proximity may have a multiplying effect. Between 1951and 1953, Tikopia in Temotu Province suffered cyclonesin December 1951, January 1952 and March 1953.Between the 1952 and 1953 cyclones a drought occurred.The recovery of crops following the 1951 and 1952cyclones was delayed by the drought; the effect of thedrought was exacerbated by the cyclones and a famineresulted.

Geological hazards may occur in combination withmeteorological hazards. The heavy rain and rough seasalong the southern coast of Guadalcanal following the1977 earthquake stopped a food relief ship from deliveringits supplies. The amount of rain which fell both beforeand after the earthquake exacerbated landsliding. Therain prior to the earthquake helped to cause landslidesduring the earthquake; the rain following the disaster,when 760 mm (30 inches) fell in the first two days ofJuly, caused more landslides, hampered overland rescueattempts and made temporary shelter difficult to find.

Impact of Extreme Eventson the RecordAlthough 31 cyclones have occurred in the Solomon

Islands since 1950, the cyclone damage and death recordhas been dominated by Cyclone Namu (1986) whichcaused extensive damage on a number of islands.

A similar pattern of domination by a small number ofevents is seen in the earthquake record where a total of63 earthquakes have been documented but only three,occurring in 1931, 1939 and 1977, are known to haveled to serious damage and deaths.

Destructive volcanic eruptions occur less frequently thanthe other hazards, but when they do occur they are moredevastating in terms of number of deaths. However, dueto their infrequency they may not be taken into accountwhen threats from natural disasters are considered. It isnow almost 150 years since any deaths resulted fromvolcanic eruptions in the Solomon Islands.

Overview of NaturalDisasters in the SolomonIslandsThe geography, topography and social nature of the

Solomon Islands leads to specific problems caused bynatural hazards. Reliance on subsistence agriculturemeans food aid often has to be given for some monthsfollowing the disaster until gardens have been replantedand regrowa. Because of the isolation of many of theislands, in terms of distance, limited communication, orlack of infrastructure within the islands, rapid responseto disaster is often not possible. Cyclone Anne (1988)caused extensive damage in the Reef Island, Anuta, Duffand Utupua. However, lack of boats or aircraft and theremoteness of the islands meant that early assessmentof the damage or prompt relief measures were not carriedout.

As the country is composed of many islands there isa relatively large coastal area which is susceptible totsunami. As a large per cent of the population lives onthe coast, the risk of death and damage from tsunamiis relatively high. The lack of a clean water supply insome rural areas and the interruption of health protectionprocedures following cyclones and earthquakes leads tooutbreaks of disease and subsequent deaths.

Fxonomic losses from natural disasters in an economysuch as the Solomon Islands can be enormous. Becausethe country is heavily dependent on the export of primaryproducts such as copra, cocoa, palm and wood products,which are particularly susceptible to damage in cyclones,interruption to these industries causes a significant dec linein exports. Thus, the recovery from a disaster has to bemet with a reduced income and reliance on overseasaid.

Hazard Severity andFuture RisksThe severity of a natural hazard cannot necessarily be

judged from its physical characteristics. The relativelymoderate intensity of Cyclone Namu, 2-3 on the CycloneSeverity Scale, would not, of itself, indicate the amountof damage incurred. Its slow movement over the islandsand the excessive rainfall were the main causes of damagefrom Cyclone Namu. As coastal development increasesfrom population and industrial expansion in areas suchas the Guadalcanal Plains, the risk of damage fromcyclones and earthquakes will also increase. Cyclonesof similar or greater magnitude than Namu can beexpected in the future.

The 1977 earthquake magnitude does not take intoaccount the effect of the rainfall or the effect of smalleraftershocks occurring in subsequent weeks. If the weatherhad been dry prior to the earthquake, many of thelandslides in the highlands may not have occurred. The1931 earthquake had a Richter magnitude of 8.1, andalthough it caused a great deal of damage and deaths,

AODRO NEWSLETTER 9

it did not greatly affect what is now the most urbanisedand agriculturally important area in the Solomon Islands.An earthquake of that magnitude affecting the north coastof Guadalcanal today would cause considerably moredisruption and damage.

Eruptions of Savo or Tinakula will occur again, but itis not possible to predict when. The magnitudes of thenext eruptions are also impossible to predict but maywell be greater than those of the 19th century eruptions.Kavachi and possibly Cook Volcano in the WesternProvince could be the area producing more explosiveeruptions and damaging tsunami in the future.

Conclusion andImplications for OtherPacific Island CountriesExamination of the phenomena associated with different

hazard, indicates the characteristics of the damage whichmay be expected on the different types of islands. Anumber of countries in the Pacific Islands consist of atleast one of the island types found in the Solomon Islandsand are therefore vulnerable to the same hazards. Drought,floods, cold weather and distance generated tsunamiwhich have either not been significant in the SolomonIslands, or their occurrence has not been documented,may have more impact in other Pacific Island countries.

It is essential to consider the diverse effects of hazardimpacts on each island. It is not only the position of theislands in relation to seismic and meteorological activitywhich determines vulnerability to natural hazards butalso the very nature of the islands; large coastal areassusceptible to tsunami; small low atoll islands susceptibleto wind and storm surge; active volcanic islands; steep,landslide prone mountains and short, swift flowing, floodprone rivers.

The nature of the society increases the vulnerability tohazard recovery. All of the population in some areasrely on food and shelter from local gardens and lagoons.Inundation by salt water pollutes drinking water andretards plant regrowth; the loss of trees by wind damagecauses loss of food and materials for shelter; soil erosionand burial of gardens in landslides means that there isa heavy reliance on food aid and raw materials forrebuilding for many months. Some villages and gardenshave to be abandoned. The propensity to live in"hazardous" parts of the islands also increases risk.

Due to the inaccessibility of some of the more remoteareas in the Solomon Islands, it can take some time toreach disrupted communities following a disaster. Similarproblems occur in other Pacific island nations. Assistancemay take some days to reach these areas, thus increasingthe risk of post-disaster ill-health and deaths.

The vulnerability to cyclones depends on the latitudeand longitude of the country and the majority of the

Pacific Islands lie within the tropical cyclone zone. Stormsurges and strong winds associated with cyclones are amajor cause of deaths.

Views of the most damaged and deadly areas and themost damaging and deadly hazard change according tothe length of the hazard record considered. It is evidentthat cyclones dominate the short (40 year) record andearthquakes become important in the longer, 80 yearrecord. In the much longer record of about 200 years,volcanic eruptions are the major cause of deaths butcause damage to smaller areas than earthquakes orcyclones. The effects that a few events have on the numberof deaths and/or damage in the record of natural hazardshighlights the importance of extreme events in theSolomon islands. Thus, the longer the record, a moreaccurate picture of the impact of all natural hazards isobtained.

The study of natural hazards in the Solomon Islandshas produced useful and surprising results. Theidentification of island and area specific effects of thevarying hazard phenomena allows a more consideredapproach to be taken towards hazard mitigation and amore efficient targeting of aid. Studies in other PacificIsland countries could take a similar approach byconsidering the effect of alHiazard^ogetherrather thanindividual hazards, and tnereDyDuTrarrrg<rTCgronal viewof all natural hazards in the Pacific Islands.

AcknowledgmentsThanks are extended to Joe Barr for his continued interest

in the project and to Neil Flood for his valuable GISexpertise.

An AppealIn our studies of the natural hazards and disasters in

the Pacific we have found accounts in old missionarybooks, magazines and reports extremely useful.Undoubtedly, we have found only a fraction of thismaterial. We would be most grateful for any informationyou have. Please write c/-School of Earth Sciences,Macquarie University NSW 2109, phone (02-805 8426).or fax (02-805 8428). v X

REFERENCES

Bayliss-Smith, T.P., 1988. The role of hurricanes in thedevelopment of reef islands, Ontong Java Atoll, Solomon Islands.The Geographical Journal, Vol. Io4(3):377-391.

Blong, R.J., Radford, D and Flood, N., 1991. Natural disastersin the Solomon Islands, Final report to Australian InternationalDevelopment Assistance Bureau, Volume 4.

Blong, R. &D. Radford, Deaths in Natural Hazards in the SolomonIslands, Disasters, in press.

Cooper, A. K., Bruns, T.R. & R.A. Wood, 1986. Crustal Structureof the Solomon Islands Intra-Arc Basins from Sonobuoy SeismicStudies In Geology and Offshore Resources of Pacific IslandArcs - Central and western Solomon Islands. Circum-PacificCouncil for Energy and Mineral Resources Earth Science Series,Volume 4. Houston, Texas.

Exon, N. and Johnson, R.W., 1986. The elusive Cook volcanoand other submarine forearc volcanoes in the Solomon Islands.Journal of Australian Geology and Geophysics, 10, 77-83.

Fisher, N.H., 1957 Catalogue of the Active Volcanoes and Solfatarafields of Melanesia.Catalogue of the active Volcanoes of theWorld, Part IV Melanesia. Naples, Italy.

I