Susan L. Cutter

During the past three decades, we have seen escalation in the damages caused by natural hazards (van der Wink et al. 1998). It seems as though every year, Americans are recovering from one natural disaster after another—earthquakes (Loma Prieta in 1989, Northridge in 1994), hurricanes (Hugo in 1989, Andrew in 1992, Floyd in 1999), fires (Oakland-Berkeley in 1991), and flooding (Mississippi River in 1993, North Dakota in 1997) to name but a few. Disaster movies, a mainstream genre in Hollywood, add to the perception that disasters are happening more often. The box office success of The Grapes of Wrath and the more recent Twister, Dante’s Peak, Volcano, and Armageddon coupled with a host of made-for-television movies on disaster themes (volcanic eruptions, tornadoes, asteroids), capture our imaginations and lead many people to conclude that disasters are common occurrences, certainly more prevalent today than in the past.

The recent occurrence of many of these events and the hype surrounding fictional disaster movies also leads to a perception that many of these hazards are concentrated in one region or another. Certainly, California immediately comes to mind in both fictional and nonfictional portrayals of a disaster-prone area. The unique marketing gimmick for

the movie Volcano touts “the coast is toast” when referring to Los Angeles in posters and video trailers. California’s image as “the disaster state” is assured in the minds of the mass media as well as most Americans. However, California is not alone. Florida and Kansas (the “Wizard of Oz” effect) are other places that people think are quite disaster-prone. Are these regional stereotypes reflective of the actual occurrence of hazard events? Are we exposed to more hazards now than in the past or are the economic losses from hazards simply escalating and thus capturing our attention?

This book explores both questions through an examination of the temporal and spatial trends in hazard events and losses during the past three decades. We hope to provide some understanding of the changing nature of hazards and hazards assessment, the technological innovations that have improved our ability to display and analyze hazards data, and how these innovations in understanding and technology can reduce local vulnerabilities to hazards through improved mitigation. Our purpose is twofold. First, we want to illustrate the geographic dimensions of hazards—where they occur, why they occur where they do, who is and which places are most vulnerable, and what can be done to reduce local vulnerability. Second, we want to demonstrate the necessity of the hazards (and vulnerability) assessment process and link it to longer-term mitigation and hazards reduction at the local level. Only after society begins to think seriously about the environmental context within which people live and work can we make informed choices regarding the level of hazardousness individuals and communities are willing to bear and at what cost to themselves and the nation.

Within the broad community of hazards researchers and practitioners, hazard, risk, and disaster are terms that are used interchangeably, although they do have different meanings (Cutter 1993, 1994, Kunreuther and Slovic 1996, Quarantelli 1998, Mileti 1999). A hazard, the broadest term, is a threat to people and the things they value. Hazards have a potentiality to them (they could happen), but they also include the actual impact of an event on people or places. Hazards arise from the interaction between social, technological, and natural systems. They are often described by their origin—for example, natural hazards (earthquakes) and technological hazards (chemical accidents)— although this classification is losing favor among the research community because

many hazards have more complex origins. For example, in many parts of the world, deforestation has resulted in increased runoff, which then leads to catastrophic downstream flooding. Is this a natural or a socially induced hazard? Or consider the use of technology to control nature, such as dams and levees. The levees may hold during normal-rainfall years, but they could fail during abnormally wet years. Is a wet-year levee break and the subsequent flooding that follows a technological, natural, or environmental hazard? As can be seen, hazards are partially a product of society and thus it is impossible to understand hazards without also examining the context (social, political, historic, environmental) within which hazards occur.

Risk is the probability of an event occurring, or the likelihood of a hazard happening (Presidential/Congressional Commission on Risk Assessment and Risk Management 1997). Risk emphasizes the estimation and quantification of probability in order to determine appropriate levels of safety or the acceptability of a technology or course of action. Risk is a component of hazard.

Generally speaking, a disaster is a singular event that results in widespread losses to people, infrastructure, or the environment. Disasters originate from many sources, just as hazards do (natural systems, social systems, technology failures). Although there are many perspectives on what constitutes a disaster (Quarantelli 1998), we will stick to the simple definition presented earlier.

As suggested elsewhere (Kates 1978, Whyte and Burton 1980, Krimsky and Golding 1992, Kasperson et al. 1995, Hewitt 1997, Hamilton and Viscusi 1999), the distinction between hazard, risk, and disaster is important because it illustrates the diversity of perspectives on how we recognize and assess environmental threats (risks), what we do about them (hazards), and how we respond to them after they occur (disasters). The emphasis on hazard, risk, and disaster is also reflective of different disciplinary orientations of researchers and practitioners. Historically, the health sciences, psychology, economics, and engineering were concerned about risks—their quantification, mathematical attributes, and use in decision making. Geographers and geologists were primarily interested in hazards, whereas sociologists captured disasters as their intellectual domain. However, as the nature of hazards, risks, and disasters became more complex and intertwined and the field of hazards research and management more integrated, these distinctions became blurred as did the differentiation between origins as “natural,” “technological,” or “environmental.”

In the first assessment of natural hazards research, White and Haas (1975) devoted an entire chapter to the social acceptance and tolerance of risks and hazards. In the second assessment, Mileti (1999) calls for an entirely new philosophical approach in dealing with hazards and reducing losses from disasters. This new perspective emphasizes (1) the interactions among social and natural systems, and the built environment; (2) the notion that hazards and disasters are acts of people, not acts of divine intervention; and (3) that unsustainable environmental practices increase vulnerability to hazards and disasters and thus hinder movement toward sustainability.

White and Haas called for improved research on human adjustments to hazards and dissemination of that research to local and state officials. Mileti says that the shift toward a sustainable approach to hazard mitigation and reduction will require a number of important steps. Among them are (1) conducting a national hazards and risk assessment; (2) building national databases on hazards losses, mitigation efforts, and the social aspects of disasters; and (3) improving the use of sophisticated technology to process and evaluate risk and hazards data. As Mileti (1999) states:

How did we get from one perspective to the other? Since 1975, risk assessment and hazards assessment have taken on very different meanings and conceptualizations. This has led to different, yet parallel, streams of research and the development of two distinct paradigms, hazards analysis and risk assessment, each with its own constituency, methodological approach, and vigor. These two approaches dominate environmental hazards research today but they are still not fully integrated into a comprehensive assessment of hazards and methods for reducing or mitigating the escalating costs at the local, regional, and national levels.

The basic underpinning of the hazards paradigm is reflected in Harlan Barrows’ presidential address to the Association of American Geographers (AAG), titled “Geography as Human Ecology” (Barrows 1923). In that address, he suggested that society interacts with the physical environment and this interaction produces both beneficial and harmful effects. This relationship between people and their environment is further viewed as a series of adjustments in both the human-use and natural-events systems. Acknowledging Barrows’ conceptual stance, Gilbert F. White (his student) undertook a series of floodplain studies during the 1940s and 1950s to offer a pragmatic element to Barrows’ viewpoint. From these studies, the natural hazards paradigm emerged (Burton and Kates 1986). Initially, the natural hazards paradigm concentrated on five thematic areas:

1. Identification and mapping of the human occupance of the hazard zone

2. Identification of the full range of human adjustments to the hazard

3. Study of how people perceive and estimate the occurrence of hazards

4. Description of the processes whereby mitigation measures are adopted, including the social context within which that adoption takes place

5. Identification of the optimal set of adjustments to hazards and their social consequences.

A further refinement of these thematic areas led to the formulation of systems models to provide causal mechanisms for linking natural events and societal responses. Examples of these include the human adjustment to natural hazards model (Kates 1971) and the human adjustment to the risk of environmental extremes model (Mileti 1980). In addition to advancements in theory, the universality of the hazards paradigm was tested using a wide range of hazard experiences in different cultural contexts. The resulting volume (White 1994) provided detailed comparative case studies from different world regions and, today, still remains as one of the classic examples of hazard field studies.

Critics of the natural hazards paradigm (Hewitt 1983) reacted to the causal sequencing and explanations put forth about how individuals and societies adjust to hazards. Instead, they suggested that cultural, eco-

nomic, political, and social forces have intensified hazards and made people more vulnerable (Blaikie et al. 1994, Kasperson et al. 1995, Hewitt 1997). More recent models place “hazards in context”—a framework that expands the traditional natural hazards perspective to include the social and political contexts within which the hazard occurs. In other words, this approach identifies factors that constrain or enable our understanding and response to hazards (Mitchell et al. 1989, Palm 1990). The contemporary hazards paradigm seeks to develop a dialogue between the physical setting, political-economic context, and the role and influence of individuals, groups, and special interests in effecting adjustments to hazards (Quarantelli 1988, Comfort et al. 1999). It does not matter where this perspective is practiced, be it sociology, geography, or the other social sciences, because the elements are essentially the same.

Most people point to Starr’s (1969) seminal article on social benefit versus technological risk as the beginning of quantitative risk analysis and the development of the risk paradigm, although antecedents are found much earlier (Covello and Mumpower 1985). Quantitative risk assessment tries to define the extent of human exposure to a wide range of chemical, biological, or physical agents and the number of expected or excess deaths or increased cancers as a consequence of the use of those agents. It has also been used to assess the potential for catastrophic accidents in technological systems such as nuclear power plants (Perrow 1999).

Recognizing the need to advance research and applications in risk analysis and management, the National Science Foundation (NSF) initiated a program in 1979 to support extramural research in risk analysis and elevate the visibility of this emerging paradigm within the foundation. The early program focused on social science applications and was known as the Technology Assessment and Risk Analysis program (Golding 1992). In the early 1980s the program moved to the social and economic sciences directorate. Today, the Decision, Risk, and Management Science program at the NSF is the primary source of funding for risk analysis research.

Drawing from many fields, the interdisciplinary risk assessment field became institutionalized in 1980 with the establishment of the Society for Risk Analysis. This association includes both researchers and practi-

tioners with interests in health, safety, and environmental risks. Their publication, Risk Analysis, contains articles representing the health sciences, engineering, physical sciences, and social sciences, all geared toward health and safety issues.

The formal acceptance of the risk paradigm occurred in 1983 when the National Research Council (NRC) published Risk Assessment in the Federal Government: Managing the Process, a report that systematized definitions and concepts as well as presenting a risk assessment framework. The risk assessment framework (still in use today) characterizes the risk paradigm. It has four primary elements: risk identification, doseresponse assessment, exposure assessment, and risk characterization (NRC 1983). The NRC model was accepted as the regulatory standard under the 1980 Superfund legislation and thus became institutionalized as part of the Remedial Investigation/Feasibility process used to prioritize the cleanup of abandoned sites. Under the remedial investigations, baseline data on the site characterization (quantities and types of hazardous materials on site), the potential pathways of human exposure (inhalation, dermal, ingestion), and technical options for cleanup were required. The ultimate goal of the risk assessment process was to identify remedial options that posed the least threat to human and ecosystem health. Because of their initial development for monitoring and assessing human health risks (especially carcinogenic risks), most risk assessments use probability estimators and other statistical techniques. The results are then phrased as a 1 in 1 million chance of dying, or a 1 in 10 million chance of causing cancer in humans, or some similar metric.

A slight deviation from the traditional probabilistic risk assessment occurred in 1987, when the U.S. Environmental Protection Agency (USEPA) published Unfinished Business (USEPA 1987). That report compared the risks associated with a wide range of environmental problems under the USEPA’s jurisdiction. Using four dimensions (human cancer risk, noncancer human health risk, ecological risk, and welfare risk), each program area was reexamined on the basis of the relative risk of each environmental problem, not just its carcinogenic potential. These risks were then rank-ordered, not defined in probabilistic terms. The relative-risk approach led to a change of emphasis within the agency—a movement away from pollution control and technological fixes and more focus on risk reduction and sustainable approaches to pollutant management. Comparative risk analysis now provides the basis for environmental policy priority setting (Davies 1996).

There was a continued broadening of the risk assessment paradigm in the early 1990s to encompass ecological risk assessments in response to pollution and ecosystem health concerns. Damages to natural systems are quantified to provide comparative data on cleanup levels and assessments of the monetary value of damages from oil spills, for example. Ecological risk assessment is the process whereby magnitudes and probabilities of an adverse effect resulting from specific human activities on particular ecosystems are determined (see Chapter 2). Throughout an ecological risk assessment, there is an assumption that discrete cause-and-effect linkages can be made either by identification of target species at risk or some other measurable surrogate that infers potential species (flora or fauna) damage.

The practice of risk assessment is fraught with methodological concerns and controversy (NRC 1994). Issues related to uncertainty in the science, variability between individuals and ecosystems, extrapolation of bioassay data to humans, and communication of risks to the public and policy makers all contribute to a lively debate among risk professionals (Dietz and Rycroft 1987). In an ideal context, risk assessment should be viewed as a process that entails an extended dialog between technical experts and interested or affected citizens (NRC 1996). In that process, it is important to get the science right and the right science, get the participation right and the right stakeholders, and develop an accurate, balanced, and informative synthesis for decision making.

One of the early issues confronting hazards researchers was to understand what people thought about natural hazards and how these perceptions influenced their choice of actions in adjusting to the sources of threats. Most of the early hazard perception work examined knowledge and attitudes about specific hazards through field studies of floods (White 1964), droughts (Saarinen 1966), and tornadoes (Sims and Baumann 1972). International perceptions were also solicited in these field studies (White 1974). These studies provided a common understanding of how people felt about extreme events: people do not recognize that they live in hazardous environments; awareness of prevention strategies makes little difference since most people know how to reduce their losses, yet the adoption of prevention measures depends on past experience with the hazard in question (Cutter 1993). While there was some input by

psychologists into these early hazard perception studies (largely through research techniques), the majority were conducted by geographers.

Risk perception took a different path with more interest in the cognitive processes that give rise to the attitudes and perceptions. Early risk perception studies helped us understand biases in our judgments about risks, errors in risk estimation, and differences between experts and the general public. The psychometric paradigm developed by Paul Slovic and colleagues used an experimental approach under controlled conditions (usually college settings) to “map” risk attitudes and perceptions, suggesting that risk perceptions were quantifiable and predictable (Slovic 1987). This research provides a scientific basis for understanding why some risks are acceptable to individuals and thus society (such as smoking or air travel), whereas others are not (radioactive waste disposal, nuclear weapons fallout) (Fischhoff et al. 1978, 1979). It also helps explain why there is such a convergence between expert judgments and those of the public (Slovic 2001).

With the overlap in interests, there is surprising little communication between hazards researchers and practitioners and the risk analysis community (White 1988). This is partly a function of the focus on extreme natural events by the hazards community, whereas the risk assessment community initially was more interested in technological risks and industrial failures. There are also methodological differences that often preclude discussion because the communities simply cannot talk to one another. Some describe this as the difference between “hard” and “soft” science. Another explanation, offered by Gilbert White (1988), suggests that risk analysis fails to include the social structure or social context within which those risks occur, a critical element for hazards researchers. There are a number of prominent social science researchers who have tried to bridge the gap between the two perspectives, but with limited success.

Despite the professional segregation, many similarities exist between the risk assessment and hazard analysis paradigms (Table 1-1). For example, hazard analysis has three components: identification, assessment, and management/mitigation. Within this, hazard identification is concurrent with the mapping of hazard zones; assessment is the determination of the vulnerability and the potential population at risk, including their socioeconomic characteristics; and hazards management/mitigation

includes the range of options or adjustments society is willing to take to respond to hazards and disasters. Conceptually then, many of the same questions are addressed in both perspectives, but the methodologies used to respond to the queries are radically different.

One of the major obstacles to the integration of the risk and hazards paradigms is this methodological divide and the exclusive use of a reductionist analytical framework found in risk analysis. The heavy reliance on quantitative methods and models often excludes people as dynamic factors. On the other hand, the hazards paradigm must move beyond a simple descriptive methodology (quantitative or qualitative) to a more

integrated analytical framework that permits the assessment of larger and more complex databases and more robust empirical field studies.

Translation of the results from researchers in hazards and risk analysis to the actual practice of risk reduction and hazard mitigation is essential. Risk analysis is most often used in regulatory standard setting or rule making (Hamilton and Viscusi 1999). Hazards assessment is more likely to be used in planning or programmatic contexts. In this regard, both have very different constituencies, but equally share a commitment for reducing societal risks and hazards. Several national and international efforts have tried to increase awareness of hazards and reduce their impacts.

In 1994, the U.S. Federal Emergency Management Agency (FEMA) released its National Mitigation Strategy in the hopes of reversing the escalating losses from natural hazards through a combination of private-public partnerships and incentives for local communities. By creating “disaster-resistant communities” under its Project Impact program, FEMA hoped to reduce the impact of hazard events on people and places through improved mitigation. It is too soon to gauge the effectiveness of this program, but the number of communities who have bought into the idea is increasing exponentially.

The International Decade for Natural Disaster Reduction (IDNDR) has just concluded. This United Nations program focused worldwide attention on the increasing losses from natural hazards and urged member nations to implement actions to reduce losses in their country. One of the outcomes of the decade was a clear shift toward mitigation rather than simple response and recovery (Press and Hamilton 1999). According to the NRC’s Board on Natural Disasters (BOND 1999), future U.S. efforts should focus on the following high-priority areas:

• Improved risk assessment

• Implementation of mitigation strategies such as land-use planning, building codes, tax incentives, and infrastructure improvements

• Improved warning technologies and their dissemination and use

• Improved use of insurance for rewarding risk reduction behavior

• Assistance to disaster-prone developing nations.

Note that the recommendations from the IDNDR are largely structural in nature and do not call for any major philosophical shifts in understanding the patterns of development, their impact on society, or how these practices contribute to hazard vulnerability. It offers a series of options that ultimately will postpone or redistribute risks and hazards, not necessarily reduce them—more akin to “business as usual.”

In contrast, the Second Assessment calls for an understanding of the underlying social processes that give rise to hazards in the first place. In moving toward a more sustainable future, “a locality can tolerate—and overcome—damage, diminished productivity, and reduced quality of life from an extreme event without significant outside assistance” (Mileti 1999:5-6). To achieve sustainability through mitigation, the following are required:

• Maintain and enhance environmental quality

• Maintain and enhance people’s quality of life

• Foster local resiliency and responsibility

• Support a strong local economy by using mitigation actions that do not detract from the economy

• Ensure inter- and intra-generational equity in the selection of mitigation options

• Adopt local consensus building.

Although the Second Assessment sets out admirable goals, many of these may not be realistic or achievable, given contemporary political and economic priorities. On the other hand, there may be no better place to begin the process of restructuring nature-society interactions.

As we have seen, not only are there divergent paths within the hazards and risk research communities, but there are also differing approaches to reducing losses domestically and internationally. With this chapter as a backdrop, we can now turn our attention to examining the evolution of American hazardscapes as we try to understand the variability in and delineation of hazard-resistant or disaster-prone places. We begin with an overview of vulnerability and hazards assessment—what these concepts mean and how we measure them.