In managing vulnerability to natural disasters, with case studies of volcanic disasters on non-industrialized islands

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Ilan Kelman

A thesis submitted in conformity with the requirements

for the degree of Master of Applied Science

Graduate Department of Civil Engineering

University of Toronto

© Copyright by Ilan Kelman 1998

Role of Technology in Managing Vulnerability to Natural Disasters,

With Case Studies of Volcanic Disasters on Non-Industrialized Islands.
Master of Applied Science 1998

Ilan Kelman

Department of Civil Engineering, University of Toronto


Technology is one tool used and misused for managing society’s vulnerability to natural disasters. Many of the difficulties encountered result from neither technical problems nor the specific natural disaster event, but manifest because society errs in applying technology or in assessing the natural hazard’s severity. This study examines, critiques, and suggests improvements in this area.

One of the most challenging steps for an engineer is defining the design criteria which should be used to anticipate a system’s response during a natural disaster, because the design load input from a natural disaster is difficult to predict and select properly. An examination of non-technological influences, preventive engineering, and relevant boundaries and scales illustrates how to prevent vulnerability to natural disasters.

The concepts and models developed are applied to case studies of volcanic hazards on non-industrialized islands. The eruptions of Mount Pinatubo in the Philippines (initial eruption in 1991) and Soufrière Hills in Montserrat (initial eruption in 1995) are examined.

Bryan Karney (Department of Civil Engineering, University of Toronto), who as this author’s supervisor, endured the trials and tribulations which traditionally befall his innocent graduate students. His intelligence, humour, and wisdom have irrevocably worked their way into this thesis, but are nonetheless surpassed by his advice one day to “follow your heart”. This author has done so, unquestionably to his benefit, but also hopefully to the benefit of those to whom this research is of interest.
David Etkin (Environmental Adaptation Research Group, Environment Canada and the Institute of Environmental Studies, University of Toronto) who cheerfully agreed to the suffer the role of The Second Reader. Invaluable advice, sources, and direction also emanated from his office, enabling this author to complete far more than he had ever expected.
The many people who kindly took the time to provide much-needed material and/or advice for this thesis, thereby enabling this author to broaden his perspective and ideas and to incorporate sources which would otherwise have been overlooked. Alphabetically, they are:

Barry Adams (Department of Civil Engineering, University of Toronto)

Brad Bass (Environmental Adaptation Research Group, Environment Canada)

Michael Brady (Transportation Department, City of Toronto)

Phil Byer (Department of Civil Engineering, University of Toronto)

John Emery (John Emery Geotechnical Engineering Limited)

Michael Kesterton (The Globe and Mail)

Chris Newhall (United States Geological Survey)

Gill Norton (Montserrat Volcano Observatory)

Simon Young (Montserrat Volcano Observatory)

Eric Miller, Jayne Leake, Linda Chow, Rosa Leo, Ampy Pural, and the Department of Civil Engineering at the University of Toronto for providing the necessary administrative support in an exemplary manner. Whenever a query was made, a document was needed, or advice was requested, the response was immediate, friendly, and accurate.
Family and Friends for being there. And to the resident canine for daily (weekends, holidays, and sleepy days excepted) risking life, paw, and bone to protect this author from being savagely murdered by the evil, ruthless Canada Post agents who dared to set foot within barking distance while carrying a horrendously lethal mailbag.
Natural Sciences and Engineering Research Council of Canada (NSERC), the University of Toronto, Bryan Karney, and my parents for financial support.
The many researchers who preceded me in this field and who paved the road upon which I travelled.

Many of the ideas and examples in this thesis were developed and analyzed during other work completed during this author’s Master of Applied Science degree. The items which contributed the most material towards, and which are most reflected in, this thesis are:
A paper entitled “A Critical Analysis of the Reaction to the 1991 Eruption of Mount Pinatubo in the Philippines” written by this author for the course IES1202S (Environmental Issues in Developing Countries) at the University of Toronto under the supervision of Professor Rodney White and submitted on April 21, 1997. This paper particularly influenced Chapter 11 in this thesis.
A paper entitled “Natural Disasters and Human Activity”, a report for the North American Commission on Environmental Cooperation (NACEC) by David Etkin (Environmental Adaptation Research Group, Environment Canada), María Teresa Vázquez (National Disaster Prevention Centre, Mexico City), and this author. This paper particularly influenced the tables and figures in Chapter 2, section 5.2.3, section 5.2.4, and Table 9-2 in this thesis.

Any errors or misinterpretations in this thesis are solely the responsibility of this author and do not reflect the support provided by those listed above and on the previous page.

Table of Contents
Abstract page ii

Acknowledgements page iii

Table of Contents page v

List of Tables page ix

List of Figures page x
Chapter 1: Introduction page 1

1.1 Natural Disasters and IDNDR page 1

1.2 Importance of Technology page 2

1.3 Case Studies page 2

1.4 Structure and Audience page 3
Chapter 2: Terminology and Context page 5

2.1 Introduction page 5

2.2 Society page 5

2.3 Environment page 5

2.4 Technology page 5

2.5 Natural Hazard page 7

2.6 Damage page 9

2.7 Vulnerability page 11

2.8 Risk page 12

2.9 Natural Disaster page 13

2.10 Management of Vulnerability to Natural Disasters page 17

2.10.1 Post-disaster Actions: Response and Recovery page 19

2.10.2 Pre-disaster Actions: Mitigation/Prevention and

Preparation/Planning page 19

2.11 Summary page 20

PART I: Concepts and Models for Technology

in Managing Vulnerability to Natural Disasters page 21
Chapter 3: Society’s Vulnerability to Natural Disasters page 21

3.1 Introduction page 21

3.2 Demographic Influences page 21

3.2.1 Individuals’ Characteristics page 21

3.2.2 Populations Characteristics page 22

3.3 Attitude and Belief System Influences page 22

3.4 Economic Influences page 26

3.5 Political Influences page 27

3.6 Conclusions: Vulnerability and Technology page 28

Chapter 4: Tool of Technology page 29

4.1 Introduction page 29

4.2 Role of Engineers page 29

4.3 Framework Used by Engineers page 29

4.3.1 System page 29

4.3.2 Load page 31

4.3.3 Response page 31

4.3.4 Using the Framework page 31

4.4 Challenges in Understanding the Load page 32

4.4.1 Understanding Natural Disasters page 33

4.4.2 Using Past Experiences to Define Problems page 35

4.4.3 Designing for Every Potential Scenario page 37

4.5 Conclusions page 39
Chapter 5: Preventive Engineering page 40

5.1 Introduction page 40

5.2 Preventing Natural Hazards page 40

5.2.1 Preventing Astronomical Hazards page 40

5.2.2 Preventing Biological Hazards page 41

5.2.3 Preventing Geological Hazards page 42

5.2.4 Preventing Hydrometeorological Hazards page 43

5.2.5 Challenges in Preventing Natural Hazards page 44

5.3 Preventing Vulnerability page 46

5.3.1 Technology Used for Managing Vulnerability page 46

5.3.2 Pre-Disaster and Post-Disaster Engineering page 46

5.3.3 Challenges in Using Technology

to Prevent Vulnerability page 48

5.4 Does Managing Risk Prevent Natural Disasters? page 50

5.5 Conclusions page 51

Chapter 6: Boundaries and Scales page 52

6.1 Introduction page 52

6.2 Spatial Boundaries and Scales page 52

6.3 Temporal Boundaries and Scales page 54

6.4 Psychological Boundaries page 56

6.4.1 Cultural/Philosophical Boundaries page 56

6.4.2 Mental/Emotional Boundaries page 58

6.5 Technological Boundaries page 58

6.6 Conclusions page 59

Chapter 7: Recommendations and Conclusions page 60

7.1 Review and Discussion page 60

7.2 Recommendations page 62

7.3 Conclusions page 64

Chapter 8: Interlude page 65
PART II: Case Studies: Volcanic Disasters on Non-Industrialized Islands page 68
Chapter 9: Volcanic Disasters page 68

9.1 Introduction page 68

9.2 Physical Characteristics of Volcanic Hazards page 68

9.2.1 Gas Hazards page 68

9.2.2 Gas-Solid and Gas-Liquid Hazards page 71

9.2.3 Solid Hazards page 71

9.2.4 Solid-Liquid Hazards page 72

9.2.5 Liquid Hazards page 72

9.2.6 Massless Hazards page 73

9.2.7 Indirect Volcanic Disasters page 74

9.2.8 Relative Dangers From Volcanic Hazards page 75

9.3 Society’s Vulnerability to Volcanic Disasters page 75

9.4 Volcanoes and IDNDR page 80

9.5 Summary and Conclusions page 82
Chapter 10: Volcanic Disasters and Islands page 83

10.1 Island Geography page 83

10.2 Non-Industrialized Islands page 84

10.3 Volcanic Disasters on Non-Industrialized Islands page 84

10.4 Selection of Case Studies page 85
Chapter 11: Mount Pinatubo, The Philippines (Initial Eruption 1991) page 87

11.1 The Philippines page 87

11.2 Mount Pinatubo page 90

11.3 Role of Technology page 93

11.3.1 American Influence page 93

11.3.2 Aetas page 95

11.3.3 Land-Use Planning page 96

11.3.4 Design Loads page 97

11.3.5 Technology Transfer and Cross-Cultural Communication page 100

11.4 Conclusions page 101
Chapter 12: Soufrière Hills, Montserrat (Initial Eruption 1995) page 102

12.1 Montserrat page 102

12.2 Soufrière Hills page 105

12.3 Role of Technology page 110

12.3.1 MVOT page 110

12.3.2 Political Situation with the U.K. page 111

12.3.3 Land-Use Planning and Design Loads page 113

12.3.4 Internet page 114

12.3.5 Vulnerability of Caribbean Islands page 117

12.4 Conclusions page 118
Chapter 13: Technology and Volcanic Disasters on Non-Industrialized Islands page 119

13.1 Comparison of Case Studies page 119

13.1.1 Similarities page 119

13.1.2 Differences page 121

13.1.3 IDNDR page 123

13.2 Recommendations page 124

13.3 Conclusions page 125
Chapter 14: Finalé page 127

14.1 Review and Discussion page 127

14.2 Overall Recommendations page 130

14.3 Conclusions page 131
References page 132

List of Tables

Table 2-1: Samples of Natural Disaster Sites on the World Wide Web page 8

Table 2-2: Classification of Natural Hazards page 10

Table 2-3: Examples of Natural Disasters page 14

Table 2-4: Examples of Disasters with Minimal Input from the Environment page 15

Table 2-5: Examples of Disasters Difficult to Classify as Either Natural or Non-Natural page 16

Table 4-1: Examples of Loads, Systems, and Responses for Natural Disasters page 30

Table 5-1: Examples of How Technology is Used for Natural Disasters page 47

Table 9-1: Selected Volcanic Eruptions page 70

Table 9-2: Selected Natural Disasters With Death Tolls in Excess

of the Total Fatalities Caused by Volcanic Eruptions page 76

Table 9-3: Examples of Volcanologists Killed by Volcanoes page 79

Table 9-4: Decade Volcanoes page 81

Table 11-1: Selected Volcanic Eruptions in The Philippines page 90

Table 11-2: Chronology of the 1991 Eruption of Mount Pinatubo page 92

Table 11-3: Summary of Engineering Intervention Measures

for Mount Pinatubo Rehabilitation Program page 99

Table 12-1: Selected Volcanic Eruptions on Caribbean Islands page 105

Table 12-2: Chronology of the Eruption of Soufrière Hills page 109

Table 12-3: WWW Sites Related to Montserrat’s Volcanic Crisis page 115

List of Figures

Figure 1-1: Schematic of Chapters page 4

Figure 2-1: Schematic of Terminology page 6

Figure 2-2: Impacts of Society’s Actions page 18

Figure 4-1: Framework which Engineers Apply in Designing for Natural Disasters page 29

Figure 9-1: Schematic of Volcanic Hazards page 69

Figure 11-1: Mount Pinatubo’s Location Within The Philippines page 89

Figure 11-2: Region Around Mount Pinatubo with Volcanic Hazard Zones page 91

Figure 12-1: Eastern Caribbean Islands page 102

Figure 12-2: Montserrat and Soufrière Hills page 103

Figure 12-3: Volcanic Hazard Zones for Soufrière Hills page 107

1. Introduction

This thesis is in the field of environmental engineering and thus examines how humanity interacts with--i.e., responds to, is affected by, and affects--the environment. Natural disasters are an important part of the environment, an important part of society, and have strong interactions with technology. Thus, they are an important part of environmental engineering.

1.1 Natural Disasters and IDNDR

Natural disasters occur when natural phenomena--such as lava, earth tremors, strong winds, high river levels, large waves, and temperature extremes--kill or injure people, damage property, and/or interfere with society’s expected day-to-day life. Although the production of complete and accurate data sets is fraught with difficulty, natural disasters are reported to have killed 144,000 people, injured 46,600 people, rendered homeless 4.61 million people, and affected 121 million people on average, per year between 1969 and 1995 (IFRC, 1998).

To investigate and mitigate the natural disaster problem, the United Nations (U.N.) has declared the decade of the 1990’s--though it actually covers 1990 to 2000--to be the International Decade for Natural Disaster Reduction (IDNDR). The U.N.’s General Assembly passed Resolution 44/236 on December 22nd, 1989 stating (IDNDR, 1998):

The objective of the Decade is to reduce, through concerted international action, especially in developing countries, the loss of life, property damage, and social and economic disruption caused by natural disasters, such as earthquakes, windstorms, tsunamis, floods, landslides, volcanic eruptions, wildfires, grasshopper and locust infestations, drought and desertification, and other calamities of natural origin.
This objective will be tackled through the goals (IDNDR, 1998):

To improve the capacity of each country to mitigate the effects of natural disasters expeditiously and effectively, paying special attention to assisting developing countries in the assessment of disaster damage potential and in the establishment of early warning systems and disaster-resistant structures when and where needed;

To devise appropriate guidelines and strategies for applying existing scientific and technical knowledge, taking into account the cultural and economic diversity among nations;

To foster scientific and engineering endeavo[u]rs aimed at closing critical gaps in knowledge in order to reduce loss of life and property;

To disseminate existing and new technical information related to measures for the assessment, prediction and mitigation of natural disasters;

To develop measures for the assessment, prediction, prevention and mitigation of natural disasters through programs of technical assistance and technology transfer, demonstration projects, education and training, tailored to specific disasters and locations, and to evaluate the effectiveness of those programs.

The IDNDR’s home page on the world wide web is at (last accessed by this author on January 4th, 1998). IDNDR activities include research projects, internet conferences, symposia, periodicals, and informational and educational programs. Targets are:

the achievement of national risk assessments of natural disasters;

development and implementation of national and/or local prevention and preparedness plans; and

developing and providing access to warning systems.

The activities of the IDNDR have helped to inspire and justify this thesis, because both seek to produce original research in, increase awareness of, and educate society about natural disasters. This thesis, however, is not an official publication of the IDNDR or any of its affiliated agencies. Recommendations in this thesis assume few changes to society, the environment, and technology, and so may not be valid beyond about a decade after submission. This timeframe, approximately 1998-2008ish, covers the immediate post-IDNDR period and therefore somewhat examines and assesses the results of the IDNDR.

1.2 Importance of Technology

Engineers are interested in and involved in natural disaster issues because many of their technologies--encompassing inventions, systems, approaches, and techniques--are used to manage natural disaster issues. This thesis examines these roles by looking at how society uses and misuses technology for managing vulnerability to natural disasters. Technology is not the only tool for managing vulnerability (for example, economic, psychological, and educational tools exist), but technology is the focus of this thesis, in order to contribute to the environmental engineering field and the engineering profession. This thesis examines, critiques, and suggests improvements in this realm by noting that:

technology hinders and helps in managing vulnerability to natural disasters;

how society develops and implements technology affects the successes of managing vulnerability to natural disasters;

society’s wish to manage vulnerability to natural disasters drives the creation and implementation of technology.

1.3 Case Studies

The ideas and models presented for the role of technology in managing vulnerability to natural disasters are applied to specific case studies in order to put the theory into practice. The case studies are focussed on one particular type of natural disaster in one particular type of geographical area: volcanic eruptions on non-industrialized islands. The intention of this thesis is to examine, and to apply to, society’s contemporary situation--as the IDNDR (section 1.1.) does--and so the case studies are events which occurred during the IDNDR: Mount Pinatubo, the Philippines (initial eruption 1991) and Soufrière Hills, Montserrat (initial eruption 1995). The examples in other parts of this thesis are also concentrated on contemporary events, although the importance of learning from history should not be understated and historical examples and attitudes are an inevitable component of any study.

1.4 Structure and Audience

The chapters of this thesis are not a purely linear sequence, although that is the most convenient manner of presenting them. Figure 1-1 is a schematic of the structure of this thesis with arrows indicating where one chapter follows directly from another. As well, many of the ideas presented in this thesis overlap or reinforce each other and so there is extensive cross-referencing.

The topic and assumed audience of this thesis are interdisciplinary. Technology relates directly to engineers (amongst others) and vulnerability to natural disasters relates directly to planners, environmental scientists, sociologists, emergency workers, and community workers (amongst others). Combining the two areas will work towards breaking down inhibitions and boundaries between these fields to demonstrate the importance of a wide breadth and depth of knowledge and experience. With so many stakeholders attempting to sort out such a complex problem, collaboration and cooperation are essential. Hopefully the reader will be inspired by this work to further explore and stimulate contributions of engineers and technology to natural disasters.

igure 1-1: Schematic of Chapters

2. Terminology and Context

2.1 Introduction

This chapter provides working definitions for the terminology used in this thesis. The goal is to yield clear indications of how vocabulary is used in further discussions. The definitions are not intended to be applied ubiquitously or to be exact and indisputable interpretations of the words. Instead, they provide a framework and a context for discussing issues and ideas. Words and language are used carefully in this thesis, and this chapter helps to set up that usage as well as to indicate the boundaries of this work. The terminology discussed in this chapter, and the relationships between them, are represented in schematic form in Figure 2-1.

2.2 Society

Society refers to the gestalt of individuals, groups of individuals, and cultures of homo sapiens sapiens (modern humanity) along with the interaction between these components. This thesis especially focuses on societies which are at risk from or are affected by natural disasters.

2.3 Environment

The environment refers to nature and nature’s actions; i.e., the events or activities which originate in natural processes. This thesis especially focuses on the aspects of the environment relevant to natural disasters. Although human beings originate in natural processes, they are covered by society (section 2.2) and so the term “the environment” excludes humanity and society, unless otherwise indicated. Implications of this separation are explored in section 6.4.1.

2.4 Technology

Technology refers to the tools created and used by engineers. Systems, techniques, designs, and approaches are all applicable. This thesis especially focuses on the technology applied to managing society’s vulnerability to natural disasters. The choice to use minimal technology and the choice not to use technology--which occur rarely in contemporary society--are regarded as viable methods of using technology to manage society’s vulnerability to natural disasters.

An important set of technologies is society’s lifelines: the systems which are vital to the health and safety of society, namely those used for energy, fuel, transportation, communication, waste management, and food/water production. The manner in which engineers design and use these technologies has immense impacts on society’s vulnerability.

Non-technological tools are also available to society for managing vulnerability to natural disasters. Economic tools include insurance and governmental programs for disaster financial assistance. Psychological tools include belief systems, which are often identified with a specific religion or culture.

Figure 2-1: Schematic of Terminology

(Modified from Etkin et al., 1998)

Specific examples are praying to or making sacrifices to deities believed to control natural events, and certain mindsets, such as fatalism, which impact on one’s decision-making ability. Educational tools include providing information and teaching appropriate behaviour and values. Legal tools can mandate actions such as the use of other tools in specific ways for specific purposes. Policy tools are often used for implementing other tools and, in areas such as fire suppression in parks and land-use planning, prominently involve scientists, engineers, and technology.

None of the categories of tools are independent sets. For example, educational and psychological tools overlap when teaching behaviour and values results in doctrines, such as ceremonies honouring rain deities, being passed down through generations. Legal and economic tools overlap when purchasing a certain type of insurance for an activity is required.

If technology and other tools overlap, they are relevant to this thesis because technology is a component of the tool. For example, educational and psychological tools can be used to influence society’s view and use of technology, as examined in sections 3.3 and 6.4. As well, technology can enhance, or make more accessible, an educational experience. Multimedia approaches to education about natural disasters have improved the accessibility of information about natural disasters, where the technology is readily available. Examples include the World Wide Web (Table 2-1) and compact discs such as the Disaster Preparedness and Mitigation Library freely distributed on compact disc by the Federal Emergency Management Agency in the U.S.A. Technology can also assist in providing a superficial public education through mass media, such as the special effects used for the American films Twister (1996), Dante’s Peak (1997), Volcano (1997), Deep Impact (1998), and Armageddon (1998). These films provide a general frame of reference for interest in, awareness of, and understanding certain natural disasters which otherwise might never be experienced or thought about by those who do not encounter such incidents.

The tool of technology is explored further in Chapter 4.

2.5 Natural Hazard

A natural hazard is an event or activity with root causes in the environment which is interpreted by society as posing a threat or danger to society; i.e., it has the potential to damage (section 2.6) society. Such a description tends to give natural hazards a negative connotation, but threats and dangers to society can be opportunities, trivialities, or major concerns and influences depending on the exact natural hazard and the exact context in which it is viewed. Natural hazards change the environment and change society, or have the potential to cause such changes. Change is feared and welcomed by society and thus so are natural hazards.

Table 2-1: Samples of Natural Disaster Sites on the World Wide Web

(accessed between September 1997 and June 1998)



CDERA (Caribbean Disaster Emergency Response Agency)

CRID (Centro Regional de Información Sobre Desastres) (Spanish) (English)

Disaster Connection

DPRA (Disaster Prevention & Recovery Alliance)

EERI (Earthquake Engineering Research Institute)

Environment Canada’s Environmental Adaptation Research Group

GHDNet (Global Health Disaster Network)


(International Federation of Red Cross and Red Crescent Societies)

INCEDE at the University of Tokyo

(International Center for Disaster-mitigation Engineering)

International Hurricane Center

National Lightning Safety Institute (U.S.A.)

Natural Hazards Mitigation Group at the University of Geneva

Nordic Volcanological Institute

Tephra, published by the Ministry of Civil Defence, New Zealand /tephra_index_txt.html

The Tornado Project

Tsunami Society

U.K. Volcanologists’ Home Page

WXP Hurricane and Tropical Storm data

There are four categories of natural hazards, which are usually classified as shown in Table

2-2. The categories in Table 2-2 are not free from ambiguity or inconsistency. For example:

Avalanches and glacial surges could be classified as either geological or hydrometeorological hazards.

Tsunamis are clearly hydrological hazards, yet they originate mainly from the geological hazards of earthquakes, landslides/rockslides, and volcanoes.

Jökulhlaups (glacial floods) can be either volcanic or purely hydrological in origin.

Fire is an ecosystem characteristic, albeit abiotic, and thus could be classified as a biological hazard; but, similar to drought, one of its causative factors is a lack of water and so it could be classified as a hydrometeorological hazard. As well, fire can be of volcanic origin.

Any danger from extraterrestrial creatures would be both astronomical and biological.

A typology of natural hazards can be developed, with the following characteristics (after Burton et al. (1993)):

Physical, chemical, and/or energy description of the hazard:

e.g., rapid motion (from an earthquake or landslide), heat (from lava or air temperature), or mass (from hail or lahars).

Magnitude and intensity.

Temporal characteristics:

speed of onset, duration (temporal extent), frequency (temporal dispersion).

Spatial characteristics:

areal (spatial) extent, pattern of distribution (spatial dispersion).

Predictability of the above characteristics and the quality of these predictions.

2.6 Damage

Impacts or consequences on society which would not have occurred in the absence of a specific event or activity are termed “damage to society”. Damage incorporates a wide range of impacts and consequences. Society can be affected directly through deaths; physical and psychological injuries; loss of information and personal opportunities; and destruction, displacement, or partitioning of cultures and communities. Society can also be affected though impacts on surroundings--including technology and the environment--such as changes (normally losses) to infrastructure, property, natural resources, and lifelines. Thus, individual life, individual quality of life, and collective quality of life can be affected by damage due to natural disasters. Damage is usually interpreted as being detrimental to society, and while this

Table 2-2: Classification of Natural Hazards

Hazard Category


Examples of Hazards


(extraterrestrial hazards)

hazards with origins in space

collision of celestial bodies with Earth, geomagnetic storms, solar flares


(biospheric hazards)

hazards with origins in living organisms, ecosystems, or other levels of the ecological hierarchy (see footnote 1 in section 2.6)

fire; microbial pathogens; poisonous, aggressive, or otherwise dangerous plants and animals


(atmospheric and hydrological/hydrospheric hazards)

hazards with origins in the air or water

avalanches, drought, erosion, floods, fog, glacial surges, hurricanes, icebergs, lightning, precipitation (e.g., freezing rain, hail, ice, rain, sleet, snow), storm surges, temperature extremes or fluctuations (cold and heat), tornadoes, waves, wind


(lithospheric hazards)

hazards with origins in the earth

earthquakes (and associated hazards such as tsunamis and landslides), landslides/rockslides (and associated hazards such as tsunamis), poison gas, volcanoes (and associated hazards such as fire, fumaroles (gas emissions), lahars (mudflows), jökulhlaups (glacial floods), and tsunamis)

interpretation is usually correct in the short-term, placing a value judgment on the long-term implications of most damage can be more difficult.

Damage to the environment occurs when natural disasters kill biota; destroy and divide ecological hierarchical levels1; and alter physical geography, such as transforming a river’s course, modifying a watershed, or changing altitude contours and peaks. Since this thesis generally focuses on the modern Western philosophical and scientific viewpoints (section 6.4.1), such losses are damage from the anthropocentric point of view: there is a loss of natural resources which could have been used for society. One proviso for this statement is that identifying an environmental loss of physical geography due to a natural disaster is often inappropriate, because natural disasters tend to create as much as they destroy.

For example, orogeny--the process of mountain building--occurs only due to tectonic forces and illustrates the continual balance of creation and destruction achieved by nature. Ever since the explosion of the volcano Krakatoa, Indonesia on August 27, 1883, that region of the Selat Sunda (Sunda Strait) has witnessed the births and deaths of many islands due to volcanic activity. The island of Surtsey, Iceland was created by a series of volcanic eruptions in 1963--though this creation process “destroyed” a section of the ocean. The Good Friday earthquake in Alaska (March 27, 1964) changed the elevation of more than 250,000 km2 of land, with large portions of land dropping into or rising from the ocean. Floods inundate tracts of land, often destroying much of the land and vegetation, but creating a new, fertile layer of soil. Changes to physical geography from natural disasters may be damaging, but are not necessarily detrimental.

2.7 Vulnerability

Vulnerability is the level of susceptibility to damage. With respect to natural disasters, vulnerability reflects the characteristics of the protection which society has developed against damage from natural hazards, and so vulnerability also indicates the degree of difficulty of protecting society from specific natural hazards.

Vulnerability is often indicated qualitatively as high or low, or quantitatively on a relative scale, rather than being assigned an absolute measurement or description. Therefore, it is more meaningful to look for levels of minimal or maximal vulnerability rather than for levels of zero or saturated vulnerability. The higher society’s vulnerability, the higher the expected damage from a natural disaster. Influences on vulnerability are explored in Chapter 3.

2.8 Risk

Various definitions of “risk” grace the literature, including:

Alexander (1991, p. 210), who cites UNESCO (United Nations Educational, Scientific, and Cultural Organization) and the Office of the United Nations Disaster Relief Coordinator:

Total risk = Impact of hazard Elements at risk Vulnerability of elements at risk

Blaikie et al. (1994, p. 25):

Risk = Hazard + Vulnerability

Blong (1996, p. 675), who cites UNESCO:

Risk = Hazard Vulnerability

De La Cruz-Reyna (1996, p. 600), who cites E.M. Fournier d’Albe:

Risk = Hazard Vulnerability Value of threatened area Preparedness

Helm (1996, p. 8):

Risk = Probability Consequences, although “this simple product is not sufficient in itself to fully describe the real risk, provides an adequate basis for comparing risks or making resource decisions”.

Smith (1996, p. 5):

“Risk is the actual exposure of something of human value to a hazard and is often regarded as the combination of probability and loss...risk (or consequence) [is] ‘the probability of a specific hazard occurrence’”

Stenchion (1997, p. 41):

“Risk might be defined simply as the probability of the occurrence of an undesired event”.

An alternative approach is taken by Burton et al. (1993) who avoid the use of the term “risk”, preferring to focus on “hazard” and “vulnerability”. Risk, risk analysis, and risk management are briefly mentioned on page 248 following their observation that “natural hazard research [has recently] melded with the field of risk assessment...[y]et this melding has spurned less reciprocity than might have been expected by researchers and managers concerned with reducing the threat of technological hazards” (p. 247).

The purpose of this thesis is not to enter the debate on the definition of “risk”; however, introducing a concept of risk which encompasses most of the themes mentioned in the literature is desirable. A suitable concept of risk is a combination of hazard and vulnerability (though not necessarily as the sum favoured by Blaikie et al. (1994) or as the multiplication favoured by Blong (1996)). The definition of natural hazard (section 2.5) includes the concept of probability while the definition of vulnerability (section 2.7) includes the concept of potential consequences. By viewing risk as the integration of and the interaction between vulnerability and hazard (as illustrated at the bottom of Figure 2-1), the most popular ideas from the literature are covered.

Risk is often indicated qualitatively as high or low, or quantitatively on a relative scale, rather than being assigned an absolute measurement or description. Therefore, it is more meaningful to look for minimal and maximal risk levels rather than for levels of zero or saturated risk. The phrases “a risk”, “at risk”, and “risky” imply “a high or significant risk”, which in turn implies that damage from a natural disaster would be augmented.

2.9 Natural Disaster

The manifestation of the threat or danger from a natural hazard in an occurrence that causes damage to society is a natural disaster. A natural disaster is a specific event, in contrast to a chance or probability, and usually is clearly delineated in space and time. Some examples of natural disasters are listed in Table 2-3.

Similar events in different locations or at different times can have radically differing outcomes, so defining a natural disaster in terms of exact economic or societal losses does not assist in developing a clear definition. The scale of damage necessary for producing a disaster, rather than an unfortunate incident or an inconvenience, is subjective. One community’s overwhelming disaster (such as flooding sweeping away a hamlet) has negligible impact on many other communities (such as a province, a country, and villages far away from the affected hamlet) or may provide opportunities for other communities (such as carpenters from the surrounding region).

The term “natural disaster” is in some ways a misnomer, because it implies that the disasters originate entirely in the environment. As illustrated in Figure 2-1, the vulnerability characteristics of society and the natural hazard characteristics of the environment are both required as inputs to yield a natural disaster. The term “natural disaster” simply implies that environmental input is necessary, though not sufficient. Drunk drivers and terrorists incorporate minimal environmental input to produce a hazard and can be accepted as being non-natural disasters (sometimes referred to as technological or anthropogenic disasters). Table 2-4 lists examples of disasters with minimal input from the environment.

Even with this distinction, differentiating between natural disasters and other disasters can be challenging, especially in the realm of transportation incidents. Some examples are listed in Table 2-5. Human beings can forget a procedure (March 10, 1989 on Table 2-5) or can make poor decisions (April 15, 1912 on Table 2-5). As well, an event can require environmental input, even when the disaster is clearly a problem of anthropogenic origin (December 1952 on Table 2-5). This thesis views such disasters as being non-natural for two reasons. The first reason is that the models and concepts developed in this

Table 2-3: Examples of Natural Disasters

(Tables 9-1, 11-1, and 12-1 list volcanic eruptions; Table 9-2 lists some high-fatality natural disasters)

(References listed are the main source of information for the example, although comparison with other sources may have resulted in some of the details being altered; unsourced examples were gleaned from media reports and this author’s experience).





October 10-16, 1780

Martinique, St. Eustatius, and Barbados (offshore)

Tropical cyclone

The most lethal recorded Atlantic storm to date, killing more than 20,000 people (Rappaport and Fernández-Partagás, 1997).

January 10, 1962



3,000 people died (Maloney, 1976).

Summer 1988

Central and eastern Canada and U.S.A.

Drought and heat wave

Deaths were estimated at 5,000 to 10,000 with more than US$40 billion (1988 dollars) of damage (NOAA, 1997).


near Dhaka, Bangladesh


The most lethal recorded tornado to date, killing 1,100 people and leaving 100,000 homeless (National Geographic, 1997).

July 1993

Hokkaido, Japan


The tsunami, triggered by an earthquake, killed more than 200 people (National Geographic, 1997).

January 17, 1995

Kobe region, Japan


The Hyougo-Ken Nanbu earthquake is the most expensive recorded natural disaster to date, estimated to have caused damage of US$125 billion (1995 dollars); the casualties were 5,426 dead and 26,804 injured (Kuribayashi et al., 1996; Lekkas et al., 1996).

May 1995

Dallas/Fort Worth, Texas

Hail storm

Insured property losses were estimated to be US$1.125 billion (1995 dollars; Renick, 1997).



ENSO (El Niño-Southern Oscillation)

This periodic phenomenon has been blamed for droughts, floods, tornadoes, landslides, storms, and insect infestations around the world. Estimates of damage are several thousand deaths and US$ several billion.

January 1998

Eastern Canada and U.S.A.

Ice storm and cold wave

More than two dozen people were killed, from falling ice chunks and, because the ice storm downed power lines, from fire and carbon monoxide asphyxiation from faulty heaters, and also from hypothermia.

Table 2-4: Examples of Disasters with Minimal Input from the Environment

(References listed are the main source of information for the example, although comparison with other sources may have resulted in some of the details being altered; unsourced examples were gleaned from media reports and this author’s experience).





January 18, 1915

Guadalajara, Mexico

Train crash

A train derailed into a gorge allegedly killing more than 600 people (Nash, 1976).



World War II

Some estimates put the final death toll as high as 55 million (Nash, 1976).

January 30, 1945

near Danzig, Poland

Ship sinking

The German cruise ship Wilhelm Gustloff was torpedoed by a Soviet submarine killing 7,700 people (1,000 survived) in the most lethal ship sinking to date (Nash, 1976).

September 1971

Al Basrah, Iraq


Grain contaminated with mercury was stolen and distributed, officially killing 459 people and injuring 6,071, but the true toll could have been 6,000 dead and 100,000 injured (Nash, 1976).

December 3, 1984

Bhopal, India

Methyl Isocyanate leak

The most lethal industrial disaster to date occurred when the chemical methyl isocyanate leaked from a Union Carbide plant, killing 6,400 people and injuring approximately 200,000 (Smith, 1996).

April 26, 1985

Chernobyl, Ukraine

Explosion and fire at a nuclear power plant.

After safety systems were shut down in order to test the limits of the reactor’s operating capability, the reactor core exploded starting a fire and sending radioactive material high into the atmosphere. 31 people died in order to contain the fire and material release (IAEA, 1986).

August 12, 1985

Mount Otsuka, Japan

Airplane Crash

Structural failure caused the airplane to crash, killing 520 people although 4 survived (Lisk, 1997).

July 2, 1990

Mecca, Saudi Arabia


During a heat wave, thousands of people in a tunnel panicked, killing 1,426.

September 28, 1994

Baltic Sea

Ferry sinking

The roll-on/roll-off ferry Estonia sank in less than 15 minutes killing 912 people (141 survived) after water penetrated the bow door.

Table 2-5: Examples of Disasters Difficult to Classify as Either Natural or Non-Natural

(References listed are the main source of information for the example, although comparison with other sources may have resulted in some of the details being altered; unsourced examples were gleaned from media reports and this author’s experience).





April 3, 1856

island of Rhodes, Greece

Lightning strike

Lightning struck the Church of St. John, which had a gunpowder vault, and 4,000 people died in the explosion (Nash, 1976).

May 31, 1889

Johnstown, Pennsylvania

Flash flood

Heavy snowfall and rain during 1889 coupled with 20 cm of rain on May 29-30 caused a poorly made dam, which was known to be damaged and deteriorating, to collapse, drowning 2,209 people (Maloney, 1976).


St. Lawrence River, Canada

Lightning strike

Lightning hit the John B. King, a freighter carrying explosives, causing an explosion which killed 30 people (Jones, 1997).

April 15, 1912

northwest Atlantic ocean

Ship sinking

The Titanic’s captain chose to travel at high speed through iceberg-infested waters and 1,513 people died after the ship struck an iceberg and sank (Maloney, 1976).

December 1952

London, England

The London Fog

Anthropogenic pollution was trapped by a naturally occurring warm air mass, killing 4,000 people in the short-term, and possibly up to 8,000 people in the long-term (Nash, 1976).

March 27, 1977

Tenerife, Canary Islands

Airplane collision

In dense fog, one airplane accelerating for takeoff collided with another airplane taxiing down the runway, killing 583 people (dozens survived) in the most lethal airplane disaster to date (Lisk, 1997).

August 2, 1985

Dallas-Fort Worth Airport, Texas

Airplane crash

Wind shear during a thunderstorm forced a landing jet onto an Interstate highway killing 140 people; 21 people on board the airplane survived (Lisk, 1997).

March 10, 1989

Dryden, Ontario

Airplane crash

The pilot forgot to de-ice the airplane’s wings and in the subsequent crash, 24 people died and several were seriously injured (Lisk, 1997).

August 26, 1990


Mine explosion

Naturally-occurring methane in a mine exploded killing 178 miners.

thesis are being applied mainly to hazards and disasters which are unambiguously natural: volcanoes (see chapter 9). During volcanic events, the environment is clearly the source of the hazard, and so the issue of the hazard’s origin is settled.

The second reason is that it is important to highlight society’s role in disasters, because society can and should take responsibility for managing vulnerability to disasters. The assumption that disasters are “acts of a deity” or “the fault of nature” ignores the contribution of society to vulnerability and ignores the control which society has over its own fate. Without ensuring that society understands its role, it becomes easy to start blaming nature or fate for as much as possible while avoiding society’s responsibility. For example, forest fires started by careless campers should not be blamed on the environmental hazard of a lack of precipitation or dry trees. Similarly, the bus crash into a gorge following brake failure near St.-Joseph-de-la-Rive, Québec on October 13, 1997, which killed 44 people and was Canada’s worst land transportation accident to date, should not be blamed on the environmental hazard of a steep hill.

2.10 Management of Vulnerability to Natural Disasters

Management refers to the actions which society takes in order to deal with the risk of natural disasters. Without society, there is no reason to manage any aspect of the environment, including aspects of natural disasters (and there would be no one to do the managing anyway). Managing is done for society by society and generally implies deliberate and conscious actions, although involuntary or incidental actions do contribute to management. As well, inaction and avoiding action are feasible, and at times appropriate, management strategies.

Referring to Figure 2-1, management (i.e., human activity) occurs only in the box “Society’s Activities”. Vulnerability is a state which exists; natural hazards are events and activities of purely environmental origin; and a natural disaster is a specific event. Society can modify risk (vulnerability or natural hazards) and natural disasters, but such modification occurs in the “Society’s Activities” box, which then alters the state of risk and/or the connections between vulnerability/hazards and the natural disaster event (Figure 2-2). Managing risk, managing natural hazards, and managing vulnerability are all potentially viable management strategies which could be conducted independently or together. Discussion of why managing vulnerability is the most appropriate approach is deferred to Chapter 5, with this question specifically addressed in section 5.4.

Mitigation and/or minimization of vulnerability tends to be the implied objective in managing vulnerability; however, other possibilities include:

An exact level of vulnerability is deemed to be desirable.

Reducing vulnerability below a specific threshold is deemed to be desirable.