Sunday, 1 November 2009

Disasters: the Symbolist Manifesto

Figure 1. Meaning and acceptance of disaster in historical context.
Figure 2. Metemorphosis of culture in the context of interpreting disaster.

Modernism and post-modernism

Since 1920 an impressive body of disaster research has built up in the social sciences. Cultural ecology and social adaptation to risk have been studied in great depth (Oliver-Smith 1998); so have social relations in disaster (Perry and Quarantelli 2005) and perception of hazards (Johnson and Covello 1987). However, the body of theory may be large and authoritative, but much of it relates to a world that has been swept away by the march of history. The heyday of theory production in hazard and disaster research extended from the mid-1960s to the 1970s (Barton 1970, White 1974). In this period the canons of human ecology and social relations in disaster were established (Burton et al. 1978). Since then, the world has moved on and many dearly-held tenets of research have been called into question by the relentless tide of information and communications technology, globalisation, promotion of ideology, and environmental imperatives. It is time to update theory to reflect the new realities of the 21st century world.

There have, of course, been attempts to tackle this problem. Mark Pelling (2003) called for theory that can help us understand and interpret globalisation. Some years earlier Ulrich Beck published his theory of the risk society (Beck 1992) and, as it is considered to be the principal post-modern theory of risk, it has been debated ever since. However, I argue that we do not live in a risk society: we live in a vulnerability society. There is a fundamental difference between the two perspectives: the former looks at society as technocracy from above, the latter from below, from the point of view of the vulnerable, the inveterate risk takers not the people who exercise choice.

Technology can lead us to a new post-modern interpretation of risk and disaster concerned with the ways in which it propagates meaning. Modern life involves vast new challenges in the search for meaning, huge perturbations in the human condition. Symbolism is a form of iconography or semiotics. It involves meaning as reduced to symbols, or concentrated and encapsulated in them (Jung 1964).

In recent decades the volume, flux and scope of the information that is available to people have all increased beyond any reasonable means of measurement. Unless technological collapse were to occur--which does not currently appear probable--the increase is set to continue. The pace of change is exemplified by the geometric progression in the calculating and memory power of integrated microcircuits ("Moore's law"--after Moore 1965). Humanity cannot adapt fast enough to the consequences of such changes. Full-scale adaptation would require the wholesale abandonment of cultures and large accretions of beliefs. It would require people spontaneously to free themselves from credos and superstitions, which has never yet occurred in human history.

Instead, inherited beliefs can condition people's view of disaster. At the root of this, natural calamity was once seen in a very narrow view symbolic manner based on judgement, retribution and portents (Figure 1). This constitutes one common aspect of the inherited cultural background that fuses with modern etic (i.e. universal) cultures in the process of cultural metamorphosis that is so important to the ways in which risk and disaster are perceived (Figure 2).

One of the most striking changes of the early 21st century is the realisation that problems can be solved by the instantaneous application of concepts and techniques developed very far away, through information and communications technology. This is the concept of real time. In the 1960s the geographer William Bunge (1966) started a conceptual revolution in his discipline by showing that spatial relationships were no longer literal and defined by distance in a geopolitical world in which the war front could be anywhere that an intercontinental ballistic missile could reach. The nuclear threat has relaxed, or perhaps merely changed, but Bunge's geographical topology has since become vastly more complex and significant. It is now relatively easy to involve oneself in the affairs of distant places and to make instantaneous connections.

In a highly networked world we cannot make sense of vast fluxes of information without symbolism. The pressure to interpret information has become so intense that we are creating a cartoon world of stylised relationships. It is highly amenable to symbolic interpretation, which is constantly facilitated by the accelerating pace of life.

Nonetheless, older views of disaster survive unscathed and thus coexist with the new (Figure 2). In the modern world vast populations survive with no piped water or electricity supplies. Yet even in such cases technological change has not been completely absent. Mobile telephony and internet access, for example, have penetrated some highly unlikely places. Cultural metamorphosis with a technological basis may be proceeding at different speeds in different places, but it is inevitable. It paves the way for new forms of symbolism. Perhaps it will turn out that the greatest luminary of disaster studies in the 20th century was the psychologist Karl Jung (1964).

The value of a symbolic interpretation

The first benefit is, of course, a greater understanding of people's perception of and relationships with disaster. No orders can be issued and effectively acted upon, no laws will successfully protect society, without taking into account people's perceptions, because these are what govern their predilections, choices and actions.

In the first place, symbolism equates with money. People will spend their wealth on things that have high symbolic value. The positive aspects of this involve donation, acquisition and economic support. In a negative manner there can be disequilibrium in investments and expenditures and support for inefficient forms of risk aversion (Peterson 2002). Governments will spend money because voters demand action, and that too can be related to symbolic interpretations. For example, accidents in the transportation field have had significant impacts on expenditure to reduce risks and increase safely, in some cases quite independently of the technical and economic arguments for investment but merely because public perception demands that particular ghosts be laid (Perrow 1984).

Secondly, symbolism encapsulates the essence of meaning. In the 21st century world old certainties have been swept away. Let us not underestimate the importance of the search for meaning in countless human lives that are caught in the resulting melee. One of the weakest, yet most pervasive forms of symbolism is numericism, love of numbers, or quantification of all things. Targets, statistics and quantities are a constant accompaniment to modern life. Sometimes they are vital or at least valuable, sometimes they are misleading or fraudulent. Amid the spread of rationalism--sometimes specious rationalism--measurements are the tools of influence, and sometimes the facilitators of modern conflict. In the worst case quantification is a damaging form of obfuscation (Alexander 2000). In the best case it can offer overwhelmingly convincing arguments for action and change. Through its reductive nature it is, however, one of the forms of symbolism.

Thirdly, over the last 60 years celebrity has become the life blood of mass media communication. Its power should not be underestimated. Celebrity has become a substitute for local curiosity. For many people it represents the idealised projection of their own personae, or at least the object of their fascination. In the modern world celebrity is increasingly powerful. In the most extreme cases it amounts to a pseudo-democratic form of unelected leadership. In many instances elected representatives are seen as less able, and less responsive, than entertainment celebrities, who have gradually increased their position as foci of change. Celebrity is intimately linked with popular and political views of disaster (Bronfen 2001). Moreover, celebrity is redolent with symbolism, much of it heavily manufactured by the entertainment industry and cultural organisations through astute use of the mass media.

Thus, symbolism can embody people's hopes, aspirations, fears and phobias, and a significant portion of their beliefs.

How can we use the symbolic interpretation in favour of disaster risk reduction?

First of all, it should be treated as a factor to reckon with. Media mean money. So do opinions, beliefs, communications and all the paraphernalia by which symbolism is propagated. Decoding symbolism is the key to how people react to risk and disaster--as risk takers, victims, donors, decision-makers, and so on. That process is the key to interpretation for policy, planning and action in disaster risk reduction and emergency response.

Symbolism could be used positively. Disaster risk is becoming increasing salient. In commercial culture branding and marketing have become so pervasive and spread so far that symbolism is the essence of commercial activity. Unwittingly, people have become accustomed to it. It has become second nature and the power of brands is overwhelming. In the same manner symbolism can be used to produce and promote a culture of risk reduction.


Symbolism is potentially the key to a new post-modern understanding of the social impact of disasters. This could be achieved by interpreting the role of symbolism in conditioning the pervasive new means of mass communication. Much work needs to be done to codify and amplify such interpretations and to consolidate the model. However, as profound changes in the technological underpinnings of modern life have occurred, the pace of cultural metamorphosis has accelerated. It is therefore imperative that new theory be made to help us understand the social, cultural and economic impacts of disaster in the 21st century.


Alexander, D.E. 2000. Confronting Catastrophe: New Perspectives on Natural Disasters. Terra Publishing, Harpenden, U.K., and Oxford University Press, New York, 282 pp.

Barton, A.H. 1970. Communities in Disaster: A Sociological Analysis of Collective Stress Situations. Doubleday, New York.

Beck, U. 1992. Risk Society: Towards a New Modernity. Trans M. Ritter. Sage, London, 260 pp.

Bronfen, E. 2001. Fault lines: catastrophe and celebrity culture. European Studies 16: 117-139.

Bunge, W.W. 1966. Theoretical Geography. Lund Studies in Geography. Gleerup, Lund.

Burton, I., Kates, R.W. and White, G.F. 1978. The Environment as Hazard. Oxford University Press, New York; 2nd edition: 1993, Guilford Press, New York.

Johnson, B.B., and V.T. Covello (eds) 1987. The Social and Cultural Construction of Risk: Essays on Risk Perception and Selection. D. Reidel, Dordrecht.

Jung, C.G. and associates 1964. Man and His Symbols. Doubleday, Garden City, New York.
Moore, G.E. 1965. Cramming more components onto integrated circuits. Electronics Magazine 38(8), 4 pp.

Oliver-Smith, A. 1998. Disasters, social change, and adaptive systems. In Quarantelli, E.L. (ed.) What is a Disaster? Perspectives on the Question. Routledge, London: 231-233.

Pelling, M. (ed.) 2003. Natural Disasters and Development in a Globalizing World. Routledge, London 250 pp.

Perrow, C. 1984. Normal Accidents: Living With High Risk Technologies. Basic Books, New York.

Perry, R.W. and E.L. Quarantelli (eds) 2005. What is a Disaster? New Answers to Old Questions. Xlibris Press, Philadelphia, 375 pp.

Peterson, M. 2002. The limits of catastrophe aversion. Risk Analysis 22(3): 527-538.

White, G.F. 1974. Natural hazards research: concepts, methods, and policy implications. In White, G.F. (ed.) Natural Hazards: Local, National and Global. Oxford University Press, New York: 3-16.

Wednesday, 6 May 2009

Mortality and Morbidity Risk in the L'Aquila Earthquake and Some Lessons to be Learned

The L'Aquila earthquake (Mw=6.3) occurred at 03.32 hrs local time when most people were sleeping. Analyses of world-wide patterns of casualties suggest that between 50 and 90 per cent of deaths in earthquakes occur between midnight and 6 a.m. (as seismic casualty data are notoriously irregular, the difference depends on the period to which records pertain--Alexander 1996, Jones et al. 1990). Studies in central America and Turkey highlight the importance of vernacular housing as a source of risk in nocturnal earthquakes, or, indeed, whenever people are likely to be at home (Glass et al. 1977, Angus 1997, Rodriguez 2005). That is equally true in Italy (De Bruycker et al. 1983, 1985) where the only buildings that are more vulnerable to collapse (and may on occasion be fully occupied) are ecclesiastical ones. Some of them are very large, extremely old, poorly maintained and lacking in seismic retrofit provisions.

Examination of patterns of damage in the L'Aquila earthquake suggests that it may be possible to create model damage scenarios to help examine the question of earthquake survivability. Two examples follow.

Model URM vernacular dwelling. A typical unreinforced masonry (URM) single family vernacular dwelling in a village (such as Onna) or small town of Abruzzo Region might have the following characteristics:-
* two or three storeys with an independent entrance but bounded laterally by other dwellings
* rubble masonry vertical load-bearing walls 30-40 cm thick consisting of angular limestone fragments bound together with soft lime mortar and cement rendered or covered with stucco
* hard spots caused by localised repairs, usually about 1-3 sq. metres in size
* weak zones located primarily between apertures, at roof level and at corners, or connected with utility channels and chimney recesses in walls
* a heavy roof consisting of a concrete base or assemblage of concrete, steel joists and hollow terracotta tiles overlain with asphalt sheeting and terracotta pantiles; alternatively one laid upon longitudinal wooden beams of 20-20 cm section and spacing approximately 1 m
* chimneys may consist of precast cement segments that detach and collapse during the shaking.

The ancient practice of using courses of tiles in rubble walls, which was started by the Romans and continued until the early 20th century, could be seen in a minority of buildings in L'Aquila province. It contributed to their cohesion but not to the extent of providing full anti-seismic protection.

As it weakened heavy masonry walls that lacked basic structural integrity, the practice of carving channels in walls for plumbing and electrical lines (chasements) led to many failures during the 6 April 2009 earthquake. Recesses and channels for chimneys had a similar effect.

Many failures in URM buildings were connected with mixed construction, as where rubble masonry in the original building was augmented by brick, cement block or concrete alterations (or even all three). Differing stiffness, compressibility and weight of these components would tend to complicate a building's reaction to seismic stresses.

Model RC vernacular dwelling. A typical reinforced concrete (RC) vernacular dwelling in an Abruzzo town or in L'Aquila city might be characterised as follows:-
* a three-to-five storey multiple-family condominium with a communal entrance and communal stairs
* use of smooth reinforcing bars (until the 1970s); over-economical usage and poor positioning of stirrups, poor design or construction of joints
* a heavy concrete roof with tile overlay
* hollow-brick infill wall panels that are poorly tied to the frame and may fall out or inwards
* thin, hollow-brick internal partition walls.

As a result of racking of the frame, infill wall panels tended to detach from the frame and fall in or out, perhaps fragmented by X-shaped cracking. Similarly, partition walls fractured and collapsed inside the buildings. Racking also causes pounding, fracturing and torsion at structural nodes. In some cases, the stairs detached from supports and collapsed. Finally, there were instances of heavy damage to plaster, ceilings and fixtures and overturning of furniture.

In L'Aquila there were many examples of incipient (or actual) mid-floor failure in multi-storey RC dwellings. This is indicative of inadequate stiffness with inertial effects above coupled with heavy displacement below. The latter may have been affected by seismic wave amplification in alluvial or lacustrine sediments or topographic amplification on convex hillslopes. In many cases this did not lead to collapse of the building but internal damage (i.e. to partition and infill walls) was very substantial.

With regard to both sorts of dwelling the modern practice of laying terracotta tiles on asphalt sheeting, such that the only things that secure them are weight and interlocking friction, led to the displacement of large numbers of tiles into the street. The lightest form of roofing tile used in Italy (20 x 36 cm) weighs about 1 kg, which amounts to 15 kg/m2. Curved pantiles are at least 60-100 per cent heavier than this. It is thus easy for heavy agglomerations of tiles to cascade over the edge of roofs into the street and to take cornices, balcony stonework and façade details with them.

Buildings that were not damaged to the point of partial or total collapse showed surprisingly little breakage of window glass. In other earthquakes this has been a factor in injuring people who rushed outside without adequate footwear. Likewise, collapse of light fittings was not widespread enough to create a significant glass splinter hazard.

Damage and the potential to improve instantaneous self-protective reaction

Given the complexity of failure patterns in vernacular housing it is reasonable to suppose that there is no single self-protective behaviour that would be appropriate under all scenarios for damage. Despite the controversy over the predictability of the L'Aquila earthquake,[1] it remained unexpected and very few people were prepared for it when it happened.

The obstacles to immediate and short-term earthquake preparedness fall into six categories:-
* experience: people may lack experience or have had no direct contact with the problem
* adaptability: people may fail to adapt or even perceive the need to adapt to the seismic threat
* perception may be insufficient to enable a person to understand the problem well enough to be motivated to act
* social: failure to communicate, associate and learn
* economic: failure or inability to accumulate money and invest in protection
* organisational: lack of social structure and incentive to act.

Factors that increase the risk of injury in the case of rapid exit from a building include the following:-
* battering by adjacent structures
* collapse of URM walls, as coherent slabs or in fragments
* detachment of roofs
* detachment and collapse of pinnacles, balustrades and chimneys
* demolition by falling masonry of balconies and façade details that jut out
* separation of URM walls from roofs, with collapse of cornices and upper masonry
* ejection of infill walls in RC buildings
* detachment and collapse of corners in URM buildings
* detachment and collapse of stairs
* racking distortion of apertures.

On the other hand, these are some of the factors that increase the risk of injury in the case of deciding to remain inside a building:-
* battering by detached horizontal members (wooden roof beams and steel floor joists)
* torsion, distortion and shattering of nodes in RC buildings
* detachment of roofs
* bulging and reticular cracking of walls, with detachment of rendering and stucco and eventual collapse of the structure
* X-shaped, diagonal or reticulated cracking in the weak zones between apertures
* implosion of infill walls in RC buildings and collapse of internal partition walls
* damage to ceilings and internal fittings and overturning of furniture.

In heavily damaged buildings in L'Aquila there was little indication that the "triangle of life" would have helped to save people from crush injuries or being buried by dust and rubble. Neither would sheltering under tables or desks.

The "triangle of life" has been vigorously promoted by the American Rescue Team (see but equally vigorously contested by other protagonists (Lopes 2004). It involves sheltering next to large, robust objects that block the collapse of beams and slabs and leave a triangular cavity in which a person may shelter (relatively) unscathed. In general, complete collapse of a frame building may leave some void spaces, perhaps 10-15 per cent of the resulting mound of rubble, but they can easily fill with cement, gypsum or mortar dust and fragments. Examination of the partial and total collapse of buildings in L'Aquila city and Onna suggested that the "triangle of life" approach would have been ineffective as few such cavities were present.

There is some--albeit circumstantial--evidence that when buildings were being heavily damaged the best spontaneous action would have been to retreat further inside. Running into the street would put people significantly at risk from falling masonry or the collapse of stairways. In any case, rapid egress was made difficult by doors that jammed as a result of racking distortion.

In consideration of the types and levels of damage caused in the L'Aquila earthquake, risk of death or injury can be related to damage level on the following five-point scale:-

1. Damage level: minimal indoor damage to walls, fixtures and fittings.
Personal risk: for most people, prudent behaviour ensures freedom from injury.
2. Damage level: significant damage to structure and fittings.
Personal risk: risk of moderate injury but no significant risk of death.

3. Damage level: pervasive damage and collapse of architectural details.
Personal risk: significant risk of serious injury but low risk of death.

4. Damage level: major damage and limited partial collapse.
Personal risk: strong risk of serious injury and significant risk of death.

5. Damage level: collapse of more than 50 per cent of the structure.
Personal risk: limited probability of survival.

Independently of any question of making buildings safer by retrofitting them, it would be possible to create a strategy to survive earthquakes while at home--at least under ideal circumstances of perception and commitment of householders. This would involve making an educated guess about the probable seismic behaviour of a vernacular dwelling and planning to react accordingly. The following steps are proposed:-

* Identify and avoid the riskiest forms of behaviour, such as running blindly out of the house.
* Develop criteria to identify the safest place in the house--i.e. the most robust place with the least risk of collapse--in the light of the following considerations:
- potential for detachment and displacement of roof tiles or the entire roof
- stability of cornices and external balusters
- degree of support of staircases
- possibility of battering interference with adjacent buildings that are different in size, shape and construction and thus have different fundamental periods
- heterogeneity of materials and potential for interference or complex behaviour.
* Create an egress procedure, considering the difficulties of exiting a building in an environment characterised by high levels of damage and precariousness. The procedure should identify the nearest safe refuge and assembly area.
* Identify the most dangerous places in the house and plan to withdraw from them.
* Create a mutual support network of relatives, friends and neighbours.
* Assemble a cache of small-scale emergency equipment and materials (torch, radio, hard hat, water sterilisation pills, etc).
* Instruct and train family members and ensure that drills are practiced.

The presence of an elementary school in the middle of the urban area in Onna that was of new construction and which resisted the earthquake without damage is an indication of the importance of such buildings as the potential location of command posts, points of refuge for the population and reception centres for people who cannot return home. Ideally, each neighbourhood or village should have such a building. It should specifically be designated as multi-function and should be equipped accordingly.

Scenarios for earthquakes at other times of day

Since pioneering work in Chile in 1960 (Lomnitz 1970) it has been well-known that aggregate patterns of human behaviour can have a very substantial impact on the totals and patterns of earthquake injury epidemiology. In this respect it is interesting to speculate on what the situation would have been if the L'Aquila earthquake had occurred at another time of day (and on a holiday or working day).

In the L'Aquila earthquake there was an overall death/injury ratio of 0.20 (305 deaths--plus two related heart attack fatalities--and about 1500 recorded injuries)[2], which is relatively low for medium-to-large earthquakes (0.33 has been hypothesised--PAHO 1981). The case fatality rates of 0.17 overall and 0.60 for serious and critical (hospitalised) injuries are low in the first case and high in the second, as the ratio of serious to all injuries was only 0.13, which is somewhat small by comparison with similar earthquakes elsewhere (commonly it might be 0.15-0.25).

Would it have been much different if the earthquake had occurred at another time of day or not on a Sunday or holiday?

Damage to religious buildings was serious enough that if the tremors had occurred during Sunday mass (as happened at Lisbon in 1755--Chester, 2001--and in Irpinia-Basilicata, southern Italy, in 1980--De Bruycker et al. 1985) death tolls among congregations would inevitably have been high. The spontaneous collapse of the vaulting of the Upper Basilica in Assisi after the 1997 Umbria-Marche earthquake swarm crushed four people to death and provided a clear illustration of what could happen to congregations. Moreover, 81 died in the collapse of the church in Balvano, Potenza Province in 1980. Like many churches in the Province of L'Aquila it lacked any significant resistance to seismic acceleration.

Damage to public buildings was substantial but, with the exception of the Prefecture (Palazzo del Governo), which largely collapsed, it appears to have been less than that inflicted upon vernacular housing. However, cornice collapse and shedding of rubble and roofing material into streets could have caused a significant number of fatalities and injuries (including people in cars) if the streets had been busily occupied rather than deserted, especially in the commercial cores of the city and neighbouring towns. This alone might have led to an even greater death toll.

Significant non-structural damage occurred to the L'Aquila city bus station, a steel-framed building with brick cladding. However, it is only a one-storey building and if it had been full of people there would probably have been significant injuries but few or no deaths.

Serious damage occurred to commercial and industrial premises, but in these injury tolls would probably have been limited by low density of occupancy. However, at the main hospital in L'Aquila there was significant potential for a greater number of injuries if the earthquake had occurred during the day when many more people would have been using this complex of buildings. As the damage was limited to cladding, ceiling fixtures and walls, no one died in the hospital and that would probably still have been the case if it had been more fully occupied. Nevertheless, injuries might have been concentrated around the main staircase, where damage was more substantial as a result of interference between the two structural masses of the building. Had the earthquake been stronger or more prolonged, the stairs might have collapsed and at certain times of day they could easily have been full of people trying to escape the tremors.

Distribution of fatalities in the L'Aquila earthquake

The economic viability of human settlements in Abruzzo is often related to their demographic growth or decline. Generally, the smaller, more rural or isolated settlements lose population to the larger ones where economic opportunity is greater. In Abruzzo Region a total of 81 municipalities were affected by the earthquake, and 49 of them were inserted into the Prime Ministerial Decree regarding damage of MCS intensities VI-IX.[3] Although there is considerable statistical variation (relating mainly to employment opportunities in the L'Aquila area and close to the Adriatic Sea coast and its access roads), the break-even point that divides decline from growth (measured on the basis of changes over the period 2001-7) is a population of about 1,500, which is the same as it was at the time of the last significant earthquake in the region (Alexander 1986). It is interesting to note that the eight municipalities in which fatalities occurred are all growing, on average by a healthy 3.7 per cent per decade. If deaths can be connected with building collapse in areas of poor quality housing, demographic stagnation is certainly not a factor.

The distribution of the 305 deaths involves a relatively circumscribed area 24 x 11 km in size. The density of population plays some role, as does the geotechnical and geomorphological setting, especially regarding soft sediments and piedmont location.

In considering the age and gender pattern of fatalities, it is of note that they are dominated by the 20-29 and over 70s age groups. The prevalence of mortality among old people is a common feature of major earthquakes (Liang et al. 2001), as they are less mobile, less perceptive and more frail than younger people, and they may live, as pensioners, in poorer quality housing. Moreover, the preponderance of female over male victims among the over-70s probably reflects nothing more than the greater longevity of women. However, the peak in the 20-29 age group is interesting and corresponds to findings from the Kobe earthquake of January 1995 (Osaki and Minowa 2001). This group is highly active but may lack experience of earthquakes and have little idea about what to do during them. Finally, there is a gender bias in the data that cannot be explained purely by the longevity of women. On average 43 men died to every 50 women. If the over 70s are excluded, the figure remains 47.5 men to 50 women. It begs further investigation.


Alexander, D.E. 1986. Disaster preparedness and the 1984 earthquakes in central Italy. Working Paper 55, Natural Hazards Center, Boulder, Colorado, 90 pp.

Alexander, D.E. 1996. The health effects of earthquakes in the mid-1990s. Disasters 20(3): 231-247.

Angus, D.C. 1997. Epidemiologic assessment of mortality, building collapse pattern, and medical response after the 1992 earthquake in Turkey. Prehospital and Disaster Medicine 12: 222-234.

Chester, D. K. 2001. The 1755 Lisbon earthquake. Progress in Physical Geography 25(3): 363-383.

De Bruycker, M., D. Greco, I. Annino, M.A. Stazi, N. De Ruggiero, M. Triassi, Y.P. De Kettenis and M.F. Lechat 1983. The 1980 earthquake in southern Italy: rescue of trapped victims and mortality. Bulletin of the World Health Organization 61(6): 1021-1025.

De Bruycker, M., Greco, D. and Lechat, M.F., 1985. The 1980 earthquake in southern Italy: mortality and morbidity. International Journal of Epidemiology 14: 113-117.

Glass, R.I., Urrutia, J.J., Sibony, S., Smith, H., Garcia, B. and Rizzo, L., 1977. Earthquake injuries related to housing in a Guatemalan village. Science 197: 638-643.

Jones, N.P., E.K. Noji, F. Krimgold and G.S. Smith 1990. Considerations in the epidemiology of earthquake injuries. Earthquake Spectra 6: 507-528.

Liang, N.J., Y-T. Shih, F-Y. Shih, H-M. Wu, H-J. Wang, S-F.Shi, M-Y. Liu and B.B. Wang 2001. Disaster epidemiology and medical response in the Chi-Chi earthquake in Taiwan. Annals of Emergency Medicine 38(5): 549-555.

Lomnitz, C. 1970. Casualties and behaviour of populations during earthquakes. Bulletin of Seismological Society of America 60: 1309-1313.

Lopes, R. 2004. American Red Cross response to 'Triangle of Life' by Doug Copp.

Osaki, Y. and M. Minowa 2001. Factors associated with earthquake deaths in the Great Hanshin-Awaji Earthquake, 1995. American Journal of Epidemiology 153(2): 153-156.

PAHO 1981. A Guide to Emergency Health Management After Natural Disasters. Pan American Health Organization, Washington, D.C.

Rodriguez, M.E. 2005. Evaluation and design of masonry dwellings in seismic zones. Earthquake Spectra 21(2): 465-492.

[1] See "Earthquake at L'Aquila, central Italy",
[2] A complete list of victims has been published and repeatedly updated by the newspaper Il Centro, see: http//,morto_comune,cognome&cerca=cerca
[3] DPCM no.3 of 16-4-2009, " Individuazione dei comuni danneggiati dagli eventi sismici che hanno colpito la provincia dell'Aquila ed altri comuni della regione Abruzzo il giorno 6 aprile 2009." Presidenza del Consiglio dei Ministri, Rome.

Wednesday, 8 April 2009

Earthquake at L'Aquila, Central Italy

The event

On Monday 6 April 2009 at 03.32 local time an earthquake of magnitude Mw=6.3 and hypocentral depth 8.8 km occurred with an epicentre a few kilometres southeast of the city of L'Aquila (population 73,000). Some 294 people were killed. Of the 1500 people wounded, at least 10 per cent were seriously injured. Damage has been reported in 49 municipalities and is serious in 16 of them (containing many small villages). About 28,000 people were rendered homeless and 18,000 of them were evacuated to a total of 106 tent encampments. This is the worst seismic disaster to have occurred in Italy for 29 years.

It would appear that this earthquake is typical of what happens periodically in the central Apennines. Although in recent history damaging earthquakes have been more common in the Region of Umbria, further north, L'Aquila is only 50 km by road from Avezzano, to the southeast, where 29,000 people (comprising almost one quarter of the local population and 97 per cent of that of the city) died in a violent earthquake on 13 January 1915. Moreover, an earthquake in 1984 left 11,000 people homeless in the vicinity of Sulmona, 50 km east of Avezzano.

The event of April 2009 took the form of an earthquake swarm, which is another common feature of central Apennine seismicity. Increasing foreshocks were followed by a main shock of moderate power (although very significant destructive potential) and a poorly attenuated series of aftershocks, some of which almost rivalled the main shock in size. Damage was therefore a result of both a single episode of strong motion and the cumulative effects of multiple shocks on severely weakened buildings.

Damage and casualties

Characteristically, damage appears to be concentrated in unreinforced masonry buildings of a historic nature and poorly constructed modern reinforced concrete buildings. No doubt state of maintenance and the presence of uneven repairs or mixed construction played a role, as is inevitably the case in such events. The most notorious damage appears to have occurred in major ecclesiastical and public buildings and a University of L'Aquila student dormitory.
At the world scale, the overwhelming majority of deaths in earthquakes occur at night, despite the fact that seismic events which cause casualties are evenly distributed among the phases of the day (Alexander 1996). In this case, perhaps the only scenario posing greater risk to life would have been an earthquake that occurred while churches were crowded with worshippers, as was the case in the 1980 Irpinia-Basilicata earthquake (magnitude 6.8, deaths approximately 3,000). In any event aggregate patterns of human behaviour play a large role in determining earthquake death tolls.

As major seismic events have not occurred in living memory in the L'Aquila area, it is unlikely that any of the inhabitants had personal protection plans or other ready resources. Hence there was no culture of individual self-defence against earthquakes, although the Abruzzo Region has a well-earned reputation for its civil protection organisation. Once again the role of self-protective behaviour in earthquakes remains difficult to estimate in terms of its life-saving potential. However, as with all nocturnal events, death tolls must be linked to some extent to the lack of ability to react quickly of people who are sleeping.

Mass media reaction

Initial mass-media coverage of the event followed a pattern that is thoroughly well known to students of disaster journalism. Human interest stories, coverage of VIP visits to the area, news of world reaction to the event, and efforts to convey the flavour of being at the scene of the action intermingled with updates on the statistics of casualties, homelessness and emergency responses. On a positive note, the stoicism and dignity of the survivors came over strongly in the news bulletins and was one factor that contributed to a relative lack of controversy in the reporting of the event.

Time and time again sociologists of disaster have shown that antisocial behaviour is minimised in the aftermath of disaster by the accession of the so-called 'therapeutic community' (Barton 1970). However, it is clear that looting and other spontaneous examples of bad behaviour are dear to the mass media, as they confirm the stylised popular view of disaster as the breakdown of society, as shown in countless Hollywood films. As a result, examples of anti-social behaviour tend to be seized upon and exaggerated. For example, in the 1997 Umbria-Marche earthquake swarm, the last significant seismic disaster that Italy had had to cope with, much was made of looting, but it appears that very few culprits were involved and the incidence of the phenomena was severely circumscribed. In the present case, members of the public purporting to represent the civil protection authorities sent false earthquake warnings by SMS. Others have been accused of price gouging. Much was made of this in the domestic news media, but it is highly likely that once again very few miscreants were involved-a statistically insignificant number of people. The response of the real authorities was firm and decisive.

A further aspect of press reporting shown during this disaster was the common tendency to exaggerate. Both the city of L'Aquila and the small village of Onna, 8 km to the SSE, were described as being 'destroyed'. Aerial views of the buildings of Onna show 100 per cent damage and 50-60 per cent outright collapse. Images of L'Aquila show sporadic damage, including the partial or total collapse of single large buildings and areas in which groups of buildings have battered each other down. In both cases this is far from total devastation. However, aggrandisement is a common feature of disaster reporting in any setting.

Emergency response

Highland Abruzzo is an area of relatively sparse population and the main area of damage appears to be limited to a 25 km radius around the epicentre. Hence, the civil protection response to the emergency posed no exceptional challenges other than the need to conduct rescues in precarious circumstances and to prepare for the eventuality of rainy weather. Five mixed operations centres (Centri Operativi Misti) were soon at work and relief columns were quickly mobilised by the regions of Italy. The ratio of assets to needs posed no unsolvable problems of the allocation of resources. Hence, the disaster represented only a moderate test of the Italian civil protection system, which has undergone very significant transformation and development in recent years, particularly towards decentralisation and the consolidation of organised volunteer forces. As in all seismic events, the L'Aquila earthquake confirmed the role of the National Fire Brigades Corps as the lead agency, owing to its primacy in technical rescue and making urban areas safe.

Despite the competency brought to the field by the relief forces, severe difficulties appear to have been experienced with the seismic inadequacy of buildings chosen to house the operations centres.

The earthquake prediction question

Both in Italy and abroad much attention was given to Dr Giampaolo Giuliani, a technician with connections to the Italian National Research Council, who discovered radon emissions anomalies in the days before the main shock and tried to institute an earthquake warning. Perhaps 10-20 per cent of the initial press coverage of the event was devoted to the ensuing controversy, as the civil protection authorities attempted to quash the warning and continued to state that it had not been justified.

Earthquake prediction can be divided into long-, medium- and short-term phases. In the long and medium terms, the seismicity of the central Apennines is well known, has been thoroughly investigated and has produced good estimates of the recurrence of significant earthquakes. The zone affected in April 2009 remains in the second category, that of moderate seismic risk. Classification is carried out at the level of single municipalities and is revised periodically. It is updated on the basis of data from seismic events, but these are not common enough to give a completely accurate picture. The upgrading of the area's status from one of moderate seismicity is overdue, but in any case many buildings antedate antiseismic norms and have not been retrofitted.

The short-term prediction of earthquakes has considerable allure for scientists, journalists and the public alike. However, it is beset by problems. The main ones can be summarised as follows:-

(a) There is an element of uniqueness in earthquake source mechanisms that tends to defy prediction.

(b) Earthquake source mechanisms are complex and involve many variables and factors.

(c) Radon is an inert element that is present in many rock formations. It may be released in increased quantities into groundwater as a result of the micro-fracturing that precedes an earthquake and generates it source. One might also expect variations in groundwater discharge, as evinced by fluctuating piezometric levels in wells or changes in the discharge of springs. However, world-wide experience with radon monitoring has proved inconclusive.

(d) Although at least eight physical phenomena are capable of showing definable 'signatures' in the hours before earthquakes, no single phenomenon has proved reliable enough to act as a routine predictor. The ratio of P- and S-wave velocities in background seismicity appears to be the most reliable of the phenomena, but even this is not capable of generating routine predictions. Hence, it is wise to consider all precursory phenomena together.

(e) Earthquake precursors are diagnostic of strain in the earth's crustal materials, but not necessarily of the sudden release of that strain.

(f) Even where earthquakes have successfully been forecast in the short term, for example at Haicheng in China in 1975, the prediction has proved difficult to replicate subsequently. In fact the Chinese failed to predict the 1976 Tangshan earthquake, which caused the largest toll of casualties of any in the 20th century.

(g) All scientific prediction of earthquakes is probabilistic and probabilities lead to dilemmas about how justified remedial action is. Moreover, most predictions have involved either low probabilities of long time-windows of validity, which makes an emergency response exceedingly difficult (Alexander 2007).

In 1985 the Garfagnana area of the Tuscan Apennines was the scene of a short-term earthquake prediction that was communicated to the population. No earthquake occurred during the days covered by the prediction, or in the subsequent years. However, the public reaction involved significant disruption to normal life, with associated costs and stresses. The exercise was not repeated during the subsequent 24 years.

The Giuliani prediction may or may not have been justified by the available data, but there is little point in issuing a forecast if the warning system is incomplete. Natural hazard warnings should consist of a scientific or technical, an administrative and a social component (see figure). If any of these is lacking or inadequate, the warning process is likely to fail, as it would have done in this case, for no adequate mechanism existed to induce a good preventative reaction on the part of the public of L'Aquila. Hence, as much as any improvement of science, earthquake warning in central Italy would require a cultural change towards personal, family and workplace preparedness and constant sensitivity to the issue, including during protracted periods of seismic quiescence. In short, people would have to have personal disaster preparedness plans. Currently, there are no signs that this will occur and no trends in that direction.


Alexander, D.E. 1996. The health effects of earthquakes in the mid-1990s. Disasters 20(3): 231-247.

Alexander, D.E. 2007. Making research on geological hazards relevant to stakeholders' needs. Quaternary International 171/172: 186-192.

Barton, A.H. 1970. Communities in Disaster: A Sociological Analysis of Collective Stress Situations. Doubleday, New York.

Wednesday, 18 March 2009

Society's Resilience in Withstanding Disaster

Figure 1. Configuration of problems and systems in future disaster risk reduction.

al-wad' ash-shadh (Arabic: a perplexing predicament)

This set of notes is intended as a discussion primer with respect to four questions, which will be considered one by one.

1. In terms of defensive measures, what action should we be taking to reduce vulnerability or prepare responses?

"Court disaster long enough, and it will accept your proposal." (Mason Cooley)

An objective assessment of the relative seriousness of hazards and threats is long overdue. However, because it requires the ability to estimate the impact of future events, the task is not easy. Futurology is at the mercy of changes in society and global trends in economy, strategic stability and international risks.

Vulnerability is the propensity to suffer harm (damage, casualties, loss of income or revenue, loss of function, and so on). In essence it is a holistic phenomenon, but for the purposes of analysis it can be broken down into components: physical, social, economic, cultural, etc. In analogy to the way in which friction is an inherent phenomenon that materialises when it is mobilised by the application of a force, so vulnerability is inherent and responds to the appearance of a hazard. The larger the hazard, the greater is the vulnerability.

Resilience is a concept that is derived by analogy from rheology, the science of materials behaviour. It signifies the ability of society to absorb and resist the shocks and pressures caused by disaster or crisis. Resilience may be an inherent property or it can be created.

Is resilience the opposite, or reciprocal, of vulnerability? Does any initiative that increases resilience automatically reduce vulnerability, or are the linkages more sophisticated?

What is the greatest threat that we face? (and who exactly are 'we'?). In terms of the world economic system, the leading candidates are as follows:-

* A global pandemic of H5N1 influenza (not spread by birds), composed of repeated, virulent waves of infection to which vaccines will be made available too late to help the majority of the people at risk. The main effects of the pandemic would probably be felt over a two-year period. The impact on healthcare, communications, travel, commerce, entertainment, tourism, and basic services would be profound in the extreme.

* A major radioactive contamination of a highly populated area, especially if the locality is also a node of international importance for communications, commerce and travel. Nuclear terrorism, the use of a nuclear bomb, or meltdown of a reactor with radiation plume release are all potential sources of hazard.

* Coordinated, terrorist attacks on critical infrastructure using an innovative strategy (whatever it may be) and leading to severe curtailment of world economic activity as a result of the combined effects of damage, precautionary (and hence restrictive) measures and public anxiety (leading to lack of investment).

* A major volcanic eruption at least as great as that of Tambora, 1815, or Krakatau, 1883 (in Indonesia), the two worst eruptions of historical times. Climatic effects could be severe over a four-year period, with major impacts on the production of food. A modern instance of something like the Krakatau eruption would produce water wave and shockwave effects that would be far worse than those of the 2004 Indian Ocean tsunami.

* A major earthquake could generate significant effects. The greatest risks are found in Tehran, Istanbul and Tokyo. Scenarios for the last of these predict $3,000 billion in losses and domino effects on world capital markets.

* Rather less likely to create change is a 'superstorm' that travels across one of the main concentrations of population and commercial activities, devastating it.

Taken together, these hazards are about equally divided between civil defence and civil protection concerns. The difference lies in the means of organisation and participation. Civil defence is usually a 'top-down' system co-ordinated nationally; civil protection may be harmonised from above, but is a locally-based, 'bottom-up' system (Alexander 2002). The former is appropriate to counter-terrorism activities and the latter to most other forms of incident or disaster. It is essential to maintain the right balance, despite the difficulty of determining which event or events will be dominant in the future. It should be noted that, no matter how large the area affected, all disasters are local events, because the local area is inevitably the theatre of relief operations.

In Europe, excessive concentration on counter-terrorism activities could leave the continent open to a fiasco similar to the impact of Hurricane Katrina on the United States in 2005, in which the structures, organisation and resources were poorly adapted to cope with the impact of a major natural disaster.

In summary, we may ask whether measures designed to reduce vulnerability automatically create resilience, and do measures designed to create resilience automatically reduce vulnerability? Furthermore, what should the relationship be between civil defence and civil protection systems: which should predominate and under what circumstances? And what sort of event is likely to catalyse radical change?

2. To what extent should risk-avoidance take precedence over normal life?

"A reasonable man adopts himself to the world.
An unreasonable man persists in trying to adapt
the world to himself. Therefore, all progress depends
upon the unreasonable man." (George Bernard Shaw)

Modern western societies are becoming increasingly intolerant of risk, yet risk aversion is expensive, inefficient and usually irrational. Already, there are many cases in which risk avoidance (or risk minimisation) is normal life, whether it be a deliberate choice or something that is imposed by rules and regulations. Hence, the provision of security accounted for 7-8 per cent of the cost of running airports ten years ago but the figure has now risen to 36-38 per cent.

The increasing complexity of western society has led to a form of abnegation of responsibility for personal risk management. Whereas 60 years ago people were accustomed to fending for themselves, they now depend on networks of organisations and services to a greater extent than ever before. Disaster thus becomes a form of 'betrayal by the authorities' (Horlick-Jones 1995), who failed to provide the necessary security or safety.

The development of the global market economy has exported risk to places that are ill-equipped to reduce it. In a certain light, international terrorism can be seen as an attempt to repatriate risk to some of the places it came from (cf. Wisner 2003).

Culture is an elusive phenomenon that is difficult to analyse and characterise but is nevertheless a fundamental ingredient of emergency preparedness and disaster risk reduction. Work with culture and it will facilitate operations; work against it and it will block initiatives. Culture can be changed, but the process tends to be slow, laborious, expensive and inefficient. Nonetheless, it is essential. The challenge of the 21st century is to create a culture in which people will take more responsibility for their own safety and risk management. The process is becoming too complex and substantial to be left entirely to the experts.

In synthesis, human life has always adapted itself to risk and there is no reason why it should cease to do so now. Indeed, greater adaptation to risk could be considered to be a means of ensuring greater contact with normality despite the forms of social isolation created by modern technology. The fundamental question concerns what form the adaptation should take. It must blend judicious use of welfare with 'informed consent' on personal and public assumption of risks.

The risk agenda needs to be reorientated towards a more objective assessment of the relative importance of different hazards and threats, one that is not dependent on the priorities of particular factions, parties and interest groups.

3. Should we reconsider the value of sophisticated technology?

"It has become appallingly obvious that our technology
has exceeded our humanity." (Albert Einstein)

"The first rule of any technology used in a business
is that automation applied to an efficient operation
will magnify the efficiency. The second is that
automation applied to an inefficient operation will
magnify the inefficiency."
(Bill Gates)

"The system of nature, of which man is a part,
tends to be self-balancing, self-adjusting, self-cleansing.
Not so with technology."
(E.F. Schumacher)

In brief, the problems with technology in relation to disasters are as follows. First, disasters and emergencies are essentially social problems and they require solutions that are derived socially. Secondly, no technology is infallible and hence its malfunctioning could become the source of disaster in its own right. Hence, cultural values that see technology as the ultimate solution to problems are capable of creating vulnerability. Finally, technology can too easily be an end rather than a means. The benefits of technological projects designed to reduce disaster need to be assessed critically and with detachment, especially as they increasingly tend to be expensive and to consume many resources. The use of technology in a disaster area should be determined by the salience of problems that need solutions, and not vice versa.

In synthesis, more effort should be made to quell the tendency to seek technological solutions for social problems. Distinct dangers are associated with the application of ever more sophisticated technology in complex situations of disaster and risk, for complexity can be self-multiplying. Augustus Caesar (63 BC--AD 14) said that the more complex a problem is, the simpler should be the solution.

Current plans for the development of technology should only be approved if their social implications and benefits are clear, and their potential complicating effects and vulnerabilities are known and can be dealt with.

4. Is greater international cooperation needed?

"...cooperation, which is the thing we must strive for today,
begins where competition leaves off." (Franklin D. Roosevelt)

The great geographical variety of political systems, administrative structures, cultures and hazards rules out the creation of a single emergency preparedness system at either the world or the continental scale. However, this should not inhibit international co-operation.

Nevertheless, international standards, treaties and protocols tend to be weighed down by the solid mass of consensus that nations struggle to achieve when creating such instruments. Behind the negotiations there is a reluctance to commit resources to dealing with events that are considered hypothetical, or at least not within the purview of current legislative terms.

The international relief system is highly inefficient. Resources are sent around the world to major disaster areas and many of them arrive too late or are inappropriate. Despite decades of fine-tuning of the system, this is still true, especially concerning international search-and-rescue.

Despite decades of wisdom about shifting the balance from reacting to disasters to preparing for and preventing them, the lion's share of the resources are still committed to the clean-up, not to prior preparation. Moreover, the level of preparedness varies considerably from place to place. In the end, these are problems that can only be solved by greater international collaboration, but what form should it take?

The solutions should start from the proposition that there is no inherent reason why rich countries should have one system of disaster risk reduction and poor countries another. Organisation is not necessarily an expensive commodity and information is decreasing in price. Information technology can be relatively cheap and has proved to be versatile, portable and adaptable to diverse environments and cultures.

Co-operation needs to change its focus, or at least its emphasis, from reacting to events to new ways of implanting organisation and technology in new environments. We know very well where the world's future disaster areas are going to be. These are the places where the international community must foster innovation and cultural change--with all due local sensitivity--in terms of the adaptation of proven universal methods of disaster risk reduction to existing local capacities.

Major international programmes are needed for the transfer of knowledge, organisation and technology to the local level in places that lack capacity.


"I feel like a fugitive from the law of averages." (Bill Mauldin)

"Ah, my boy, if you spot a crowd coming down
the road, go the other way and see if they've
dropped anything." (Eric L. Jones)

I believe that sooner or later a major event will lead to a global change in attitudes towards disaster risk reduction. The first section of these notes contains some speculation about what sort of event it could be, although the picture is anything but clear. In the early 21st century capital has subsumed labour and recent history offers little indication that high death tolls could be the distinguishing feature of such an event (Alexander 2000, Ch. 2). Instead, the event that induces change would have to upset the world financial system to the extent that radical solutions become the only way of protecting it. At present, disasters represent accelerated forms of consumption of goods (Jones 2003). They are thus situations of profit and loss. A catalytic disaster would have to tip the balance so decisively in favour of loss that radical action would become essential. It is not clear which sort of event will be first to achieve that change, nor which will be the primary system by which it is confronted (Figure 1).


Alexander, D.E. 2000. Confronting Catastrophe: New Perspectives on Natural Disasters. Terra Publishing, Harpenden, U.K., and Oxford University Press, New York, 282 pp.

Alexander, D. 2002. From civil defence to civil protection--and back again. Disaster Prevention and Management 11(3): 209-213.

Horlick-Jones, T. 1995. Modern disasters as outrage and betrayal. International Journal of Mass Emergencies and Disasters 13(3): 305-315.

Jones, E.L. 2003. The European Miracle: Environments, Economies and Geopolitics in the History of Europe and Asia (3rd edn). Cambridge University Press, Cambridge.

Quarantelli, E.L. 1997. Problematical aspects of the information/ communication revolution for disaster planning and research: ten non-technical issues and questions. Disaster Prevention and Management 6(2): 94-106.

Wisner, B. 2003. Changes in capitalism and global shifts in the distribution of hazard and vulnerability. In M. Pelling (ed.) Natural Disasters and Development in a Globalizing World. Routledge, London: 43-56.

Saturday, 31 January 2009

Theoretical Notes on Vulnerability to Disaster

The word vulnerability is derived from the Latin vulnerare, meaning 'to wound'. Broadly, it refers to the exposure of a person, asset, good or activity to potential harm or loss (see Weichselgartner 2001 for a list of definitions of the term).

Several paradoxes are associated with the concept. First, vulnerability can be disaggregated for the purposes of analysis into sectors or components (such as physical, social, economic or psychological), but it is nevertheless essentially holistic--i.e. the whole entity suffers harm (Cardona 2004).

Secondly, like risk, vulnerability is a hypothetical concept, but one that nevertheless does not lack reality. It is simply not tangible: in the same way that in the physical world friction only comes into being when it is mobilised, so vulnerability only becomes manifest when it manifests itself as impact. This is one reason why the concept is difficult to measure. Confirmation of the existence of vulnerability is obtained post hoc by measuring the impact of disaster, or at least by inferring that past impacts will be diagnostic of future events. Vulnerability is thus a latent or inherent property.

One of the great achievements of disaster studies in the second half of the twentieth century was to establish that vulnerability is the principal component of risk (Hewitt 1983). In the more extreme formulations, hazard (the other main component) is regarded as merely the trigger of risk conditions, and vulnerability accounts for the bulk of the propensity to suffer harm. This formulation is commonly used when dealing with extreme poverty (Boyce 2000). As a result, it becomes easy to confound risk and vulnerability. Indeed, there is an element of circularity in the standard conceptual equation:-

Hazard x Vulnerability [ x Exposure ] = Risk --> Impact

The main consequence of this is that vulnerability can be difficult to isolate from risk. In part this reflects the complexity of socio-economic factors associated with the concept, as the physical connotations of hazard are often relatively straightforward by comparison. Essentially, hazard is active and vulnerability is passive. Hence, risk is not directly caused by vulnerability, but it is greatly, perhaps overwhelmingly, enhanced by it.

In the equation given above the role of exposure is contentious. The term 'exposure' has different meanings. In the insurance world it refers to the maximum liability for payment of compensation to policy holders (Van der Voet and Slob 2007). In the nuclear field it represents the length of time that a subject is at risk of receiving a dose of radiation, with or without some indication of the possible strength of that dose. In hazards studies, the simplest definition refers to the proportion of time that a person or asset is threatened by a particular risk (Lerner-Lam 2007).

Given the role of exposure, it is important to note that vulnerability is not an "all or nothing" concept. Many studies of risk conditions are based on the propensity for total losses. This, of course, assumes an utter inability to resist the impact of disaster. Resilience (or capacity, or coping) is a concept derived from rheology, the physical behaviour of materials, and it refers to the ability of a substance (or in this case of society) in balanced measure to absorb and resist the shock of impact. It is, of course, the inverse of vulnerability:-

( Hazard x Vulnerability x Exposure ) / Resilience = Risk --> Impact


Hazard x ( Vulnerability / Resilience ) [ x Exposure ] = Risk --> Impact

Hence, vulnerability can be partial. If it is quantifiable it can be expressed as an index or percentage relative to total loss. If it can be assessed, categories may be used, such as severity of injury relative to lethality, or degrees of loss of the structural integrity of a building relative to total collapse. In any event, many hazard impacts mobilise only a portion of vulnerability. For example, very few earthquakes cause total devastation to a city, and the patterns of seismic damage in urban environments can be highly complex (Wisner 1999).

The ability to disaggregate vulnerability into different components indicates that it can take different forms. The field of business continuity management (BCM) is founded on the notion that vulnerability has different components, which apply, for example, to the supply chain, the manufacturing or production process, relations with clients, customers and suppliers, the market value of a company's shares, its position with respect to competitors and its reputation with investors and customers. Damage in any of these sectors can activate vulnerability in other categories (Kemp 2007).

One possible interpretation of vulnerability is that it can be defined relative to the circumstances that generate it. The following model breaks vulnerability down according to its context (Alexander 1997, Özerdem and Jacoby 2006):-

- Total vulnerability: life is generally precarious because little or nothing has been done to reduce the sources and potential impacts of risk. This condition tends to apply to poor and marginalised societies which lack the resources to protect themselves.
- Economic: people lack adequate occupation and hence vulnerability refers to the precariousness of their productive activities and sources of income.
- Technological or technocratic: caused by the riskiness of technology or of the ways in which it is utilised.
- Residual: caused by lack of modernisation, in which risk conditions evolve but mitigation strategies do not keep pace with them.
- Delinquent: caused by corruption, negligence or criminal activity that puts people or assets at risk.
- Newly generated: caused by change in circumstances, for example as a result of newly emerging risks.

Such is the complexity of society that these categories need not be mutually exclusive.

If vulnerability takes different forms or has different components not only will it be multifaceted but there will also be interaction between the components. Hence, it may be additive and there may be gestalt (i.e. the whole may be more than the sum of the parts). Chains of causality, interactions between the parts and collateral and secondary vulnerabilities may come into play. Thus we may define primary vulnerability as the direct product of cause and effect. For example, if an earthquake shakes a dilapidated house the poor quality of the masonry may cause the building to collapse. No gestalt is present. Secondary vulnerability, potentially with moderate gestalt, results from the interaction of causes or the occurrence of coincidences. For instance, a building may resist earthquake shaking but not the water wave caused by the seismically-induced breaching of a dam upstream. Complex vulnerability involves high gestalt and occurs when complicated interactions between components heighten overall vulnerability. The ramified economic effects of a major earthquake in a metropolitan city would produce this.

Vulnerability can be measured or estimated directly as potential for harm or loss. However, this requires hypotheses of the potential impact of events that have not occurred but are likely to. There is, of course, scope for inaccuracy in such theorising. It can also be measured indirectly as 'non-resilience'--i.e. the failure to be robust in the face of a threatening event. The fault trees and event trees used in the risk analysis of industrial processes are an example of this and could be adapted to other forms of investigation, for example with society.

Like risk, vulnerability can be chronic or catastrophic, depending on whether it results in widely diffused malaise or concentrated disaster. It applies to known risks, adapting risks, emerging risks and unknown risks. Whereas the process of investigating vulnerability in the context of the first of these is relatively straightforward, it becomes much more difficult when applied to adapting risks (e.g. those associated with climate change) and emerging risks (e.g. pandemics). It cannot be achieved for unknown risks, the ones that will emerge in future scenarios. The management of vulnerability must involve holistic techniques that take account of the categories in which it occurs and the different degrees and levels of interaction between them (Cardona 2004). This is necessarily so, as managing vulnerability with regard to single themes and cases will merely allow it to escape into other categories and will thus not reduce it. Holistic analyses must precede holistic remedies.

Vulnerability is susceptible to the dialectic of forces that act to increase or diminish it. The concept is not static but is continually modified by forces that amplify or mitigate it. Thus the vulnerability of settlement on a floodplain can be diminished by structural and planning measures but simultaneously amplified by building new structures that are at risk of inundation. Perception is the deciding factor, providing one takes into account its links with decision-making and action. Low or inaccurate perception of hazard can perpetuate vulnerability, while high perception can lead to its reduction.

Given the dynamic environment in which it occurs, measures taken to reduce vulnerability need to be sustainable. If they are not, it will inevitably climb back again.

Sustainable vulnerability reduction is locally based, supported by the community, well integrated into legislation and planning instruments and part of a grand strategy to make life more resilient for the inhabitants of the area in question. It goes without saying that resilience depends on sustainability (Wisner 2004).


Alexander, D.E. 1997. The study of natural disasters, 1977-97: some reflections on a changing field of knowledge. Disasters 21(4): 284-305.

Boyce, J.K. 2000. Let them eat risk: wealth, rights and disaster vulnerability. Disasters 24(3): 254-261.

Cardona, O.D. 2004. The need for rethinking the concepts of vulnerability and risk from a holistic perspective: a necessary review and criticism for effective risk management. In G. Bankoff, G. Frerks and D. Hilhorst (eds) Mapping Vulnerability: Disasters, Development and People. Earthscan, London: 37-51.

Hewitt, K. 1983. The idea of calamity in a technocratic age. In K. Hewitt (ed.) Interpretations of Calamity. Unwin-Hyman, London: 3-32.

Kemp, R.L. 2007. Vulnerability assessments for public and private facilities. Journal of Business Continuity and Emergency Planning 1(3): 245-251.

Lerner-Lam, A. 2007. Assessing global exposure to natural hazards: progress and future trends. Environmental Hazards 7(1): 10-19.

Özerdem, A. and T. Jacoby 2006. Disaster Management and Civil Society: Earthquake Relief in Japan, Turkey and India. International Library of Postwar Reconstruction and Development no. 1, I.B. Taurus, London and New York, 142 pp.

Van der Voet, H. and W. Slob 2007. Integration of probabilistic exposure assessment and probabilistic hazard characterization. Risk Analysis 27(2): 351-372.

Weichselgartner, J. 2001. Disaster mitigation: the concept of vulnerability revisited. Disaster Prevention and Management 10(2): 85-94.

Wisner, B. 1999. There are worse things than earthquakes: hazard vulnerability and mitigation in Los Angeles. In J.K. Mitchell (ed.) Crucibles of Hazard: Mega-Cities and Disasters in Transition. United Nations University Press, Tokyo: 375-427.

Wisner, B. 2004. Assessment of capability and vulnerability. In G. Bankoff, G. Frerks and D. Hilhorst (eds) Mapping Vulnerability: Disasters, Development and People. Earthscan, London: 183-193.