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Two glacier avalanches from Mount Huascarán killed 4,000 people and destroyed the town of Ranrahirca and killed 15,000 people and devastated the city of Yungay in 1970, making it the most deadly glacier disaster in world history. Because these avalanches were unpredictable and uncontrollable, the Peruvian government tried more forcefully than it had during previous decades to implement hazard zoning to reduce disaster vulnerability in the Callejón de Huaylas. Local residents with different risk perceptions, however, successfully resisted zoning plans. In the process, glacier and glacial lake science became contested knowledge that various social groups sought to control. Ironically, locals opposed zoning to limit state intervention in their communities. But by inhabiting hazard zones they ultimately became even more dependent on state programs to monitor Cordillera Blanca glaciers and drain glacial lakes. As glacier experts tried to protect populations, they mediated between the centralized state and various local populations.

This chapter considers systems of interacting agents placed on networks. The agents — spins, oscillators, interacting individuals, etc. — occupy the nodes of networks and interact with each other through network links. In more complicated situations, these agents, in turn, influence their network substrates, and so the pair, a network and the system of agents, co-evolve. The chapter discusses unusual phenomena in these cooperative systems on complex networks. In particular, the Ising model on networks is considered, various synchronization phenomena, and basic game theory models. Finally, avalanches and other abrupt phenomena in many-particle systems on complex networks are touched upon.

This chapter begins with a survey of early experimental results — the Planck spectrum, the photoelectric effect, and Compton scattering — that are usually presented as evidence for the existence of photons. The photon concept is indeed sufficient to explain these results, but it is not necessary. There are semi-classical models that explain the same data without introducing photons. The crucial experiment, in which light consisting of a single photon reflects from a beam splitter, depends on the essential indivisibility of photons, and it excludes all semi-classical descriptions of light. This discussion is followed by a preview of modern methods of production and detection of individual photons, e.g., spontaneous down conversion and Silicon avalanche-photodiode counters, together with an introduction to the quantum theory of light based on the correspondence principle.

This chapter first discusses which parameters determine sensor sensitivity, and then explains the basic semiconductor physics relevant to radiation detectors. Statistical limits to energy resolution are discussed with a simple derivation of the Fano factor. Semiconductor doping and pn-junctions are explained and applied to the formation of extended detector volumes. Quantitative expressions describing charge transport and collection times are derived. The mechanism of induced charge is explained and applied to multi-electrode structures, such as strip and pixel detectors (Ramo's theorem). Charge collection in the presence of trapping and alternate sensor materials is discussed. Avalanche gain is described and applied to photodiodes. The second half of the chapter explains the basics of electronic signal acquisition with voltage, current, or charge-sensitive amplifiers. The relationship between pulse rise time and frequency response is explained together with the basic amplifier parameters that limit bandwidth. In closing, the importance of amplifier input impedance is shown.

There are at least three justifications for the examination of the geomorphology of the area in which ecosystem studies are conducted. First, the present landscape and the materials that make it up provide the substrate on which ecosystem development occurs and may impose constraints, such as where soil resources are limited, on that development. Second, the nature of the landscape and the geomorphic processes acting on it often define a large part of the disturbance regime within which ecosystem processes occur (Swanson et al. 1988). Third, the processes of weathering, erosion, sediment transport, and deposition that define geomorphic dynamics within the landscape are themselves ecosystem processes, for example, involving the supply of resources to organisms. In this last context, it is noteworthy that drainage basins (also called watersheds or catchments) were recognized as units of scientific study during a similar time period in both geomorphology and ecology (Slaymaker and Chorley 1964; Bormann and Likens 1967; Chorley 1969). The drainage basin concept, the contention that lakes and streams act to integrate ecological and geomorphic processes, remains important in both sciences and underlies the studies in Green Lakes Valley reviewed here. Over the past 30 years, Niwot Ridge and the adjacent catchment of Green Lakes Valley have been the subject of much research in geomorphology. Building on the studies of Outcalt and MacPhail (1965), White (1968), and Benedict (1970), work has emphasized the study of present-day processes and dynamics, especially of mass wasting in alpine areas. These topics have been reviewed by Caine (1974, 1986), Ives (1980), and Thorn and Loewenherz (1987). Studies of geomorphic processes have been conducted in parallel with work on Pleistocene (3 million to 10,000 yr BP) and Holocene (10,000 yr BP to present) environments in the Colorado Front Range (Madole 1972; Benedict 1973) that have been reviewed by White (1982). This chapter is intended to update those reviews in terms that complement the presentation of ecological phenomena such as nitrogen saturation in the alpine (chapter 5) as well as to refine observations and conclusions of earlier geomorphic studies.

Not long ago, at the beginning of a course I was teaching on “The Literature of the Land,” I asked my undergraduate journalism students why they were having such a hard time thinking of things to write about. What, I wondered, was so hard about nature writing? A sophomore raised his hand. As often happens, the answer came back more succinct than I could have hoped. “It's hard writing about nature in Delaware,” he said, “because there is no nature in Delaware.” There was something emblematic in this comment, something that revealed the difficulty, at first blush, that young writers have in conjuring exactly what “nature writing” means. My first impulse was to list all the nearby “nature” out there that the student hadn't bothered to recognize: the Atlantic seashore, the Delaware and Chesapeake bays, the Appalachian Mountains on one hand; and DuPont chemical factories, massive landfills, and rampant suburban sprawl on the other. But instead I paused, and let the comment hang in the air for a moment. What, exactly, were we talking about? For the nonspecialist, “nature writing” can seem especially intimidating, since it seems, at first glance, to be a subject without human drama, without a narrative trajectory, without a beginning, a middle, and an end—as opposed to, say, writing about cops, or courts, or politics, or sports. It can seem overly technical, or ponderous, or misanthropic. It can seem abstract, even irrelevant, especially to urban audiences who think of “nature” as something they encounter on boutique holidays out west. Norman Maclean's A River Runs Through It, according to legend, was rejected by a New York publisher because “it had too many trees in it.” But it isn't “nature” that is lacking, in Delaware or anywhere else. It is imagination, or perspective, or a “way of seeing.” Granted, a place like Delaware is notably lacking in the 14,000-foot mountains, Arctic fjords, and equatorial rainforests that have come to represent “nature” for suburban Americans. But this is precisely why a place like Delaware turns out to be such a useful place to talk about nature writing.

This chapter discusses the occurrence of natural disturbances and their significant effects on the forests. It focuses on two disturbances that are the most important and widespread occurrences in the Klamaths: fire and water. The chapter first discusses the fire histories of the Klamath Mountains and interactions of various species and their adaptations to fire. It examines the effects of twentieth-century fire exclusion, the loss of fire-tolerant trees due to selective harvest, and plantation forestry. The chapter then discusses the negative and positive effects of floods on forests. It also describes other disturbances such as insects, pathogens, strong winds, drought, snow avalanches, and earthquakes.

In the Bak-Sneppen model studied in the previous chapter there is no explicit notion of an interaction strength between two different species. It is true that if two species are closer together on the lattice, then there is a higher chance of their participating in the same avalanche. But beyond this there is no variation in the magnitude of the influence of one species on another. Real ecosystems, on the other hand, have a wide range of possible interactions between species, and as a result the extinction of one species can have a wide variety of effects on other species. These effects may be helpful or harmful, as well as strong or weak, and there is in general no symmetry between the effect of A on B and B on A. For example, if species A is prey for species B, then A's demise would make B less able to survive, perhaps driving it also to extinction, whereas B's demise would aid A's survival. On the other hand, if A and B compete for a common resource, then either's extinction would help the other. Or if A and B are in a mutually supportive or symbiotic relationship, then each would be hurt by the other's removal. A number of authors have constructed models involving specific speciesspecies interactions, or "connections." If species i depends on species j , then the extinction of j may also lead to the extinction of i, and possibly give rise to cascading avalanches of extinction. Most of these connection models neither introduce nor have need of a fitness measure, barrier, viability, or tolerance for the survival of individual species; the extinction pressure on one species comes from the extinction of other species. Such a system still needs some underlying driving force to keep its dynamics from stagnating, but this can be introduced by making changes to the connections in the model, without requiring the introduction of any extra parameters.

This chapter discusses the montane and subalpine coniferous forests and other vegetation of the Sierra Nevada and Cascade Ranges in California, vegetation patterns and environmental factors that affect distribution, and the role fire in spatial pattern and landscape. It also discusses some of the factors affecting vegetation, such as insects and pathogens, wind and avalanches, invasive species, air pollution, and logging.

Western European countries are subject to natural phenomena that can cause disasters. Their origins are various: geophysical (earthquakes), hydrometeorological (sea storms, floods, and avalanches), or geomorphologic (landslides). They are fairly widespread but less frequent and of relatively low intensity compared with other regions of the world; for example, an earthquake in France or Belgium is not likely to be as violent as in Greece or Japan. Some of the countries concerned, such as France and Germany, are subject to all the hazards mentioned above, while Denmark and The Netherlands are seldom exposed to earthquakes and never to avalanches because they have no mountains. Man is not responsible for phenomena such as earthquakes, but contributes significantly to the onset and aggravation of other hazards, and is sometimes largely responsible for the direct and indirect consequences, having built and maintained installations in ‘risk’ sectors. The number of victims and the cost of the damage may be high, depending on the circumstances, the intensity, and the duration of the phenomenon. Western European countries have experienced real natural disasters in the distant or recent past. Floods following a storm wave in The Netherlands in 1953 were responsible for some 2,000 deaths and damage amounting to over 3 billion Euros. Two hundred people died in the most destructive flood ever known in France in 1930 in the Tarn (Ledoux 1995). Natural phenomena such as these can recur with at least the same intensity but may entail much greater damage because of increased human occupation in the sectors concerned: the flooding submerges zones which are much more urbanized than they were in the nineteenth century. Whether prevention measures are taken depends on the level of risk which the populations concerned are prepared to accept. These measures should be associated with spatial and temporal forecasts and preceded by an analysis of the processes for these phenomena to be fully understood. In order to remove the ambiguities and the inaccuracies of terminology that are observed all too often, it is necessary in the first instance to define ‘geomorphic hazards and natural risks’, particularly in terms of the notions of risk, hazards, and vulnerability.

The cryosphere refers to the Earth’s frozen realm. As such, it includes the 10 percent of the terrestrial surface covered by ice sheets and glaciers, an additional 14 percent characterized by permafrost and/or periglacial processes, and those regions affected by ephemeral and permanent snow cover and sea ice. Although glaciers and permafrost are confined to high latitudes or altitudes, areas seasonally affected by snow cover and sea ice occupy a large portion of Earth’s surface area and have strong spatiotemporal characteristics. Considerable scientific attention has focused on the cryosphere in the past decade. Results from 2 ×CO2 General Circulation Models (GCMs) consistently predict enhanced warming at high latitudes, especially over land (Fitzharris 1996). Since a large volume of ground and surface ice is currently within several degrees of its melting temperature, the cryospheric system is particularly vulnerable to the effects of regional warming. The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) states that there is strong evidence of Arctic air temperature warming over land by as much as 5 °C during the past century (Anisimov et al. 2001). Further, sea-ice extent and thickness has recently decreased, permafrost has generally warmed, spring snow extent over Eurasia has been reduced, and there has been a general warming trend in the Antarctic (e.g. Serreze et al. 2000). Most climate models project a sustained warming and increase in precipitation in these regions over the twenty-first century. Projected impacts include melting of ice sheets and glaciers with consequent increase in sea level, possible collapse of the Antarctic ice shelves, substantial loss of Arctic Ocean sea ice, and thawing of permafrost terrain. Such rapid responses would likely have a substantial impact on marine and terrestrial biota, with attendant disruption of indigenous human communities and infrastructure. Further, such changes can trigger positive feedback effects that influence global climate. For example, melting of organic-rich permafrost and widespread decomposition of peatlands might enhance CO2 and CH4 efflux to the atmosphere. Cryospheric researchers are therefore involved in monitoring and documenting changes in an effort to separate the natural variability from that induced or enhanced by human activity.

The raw facts alone make mountains worthy of geographic interest: mountains constitute 25 per cent of the earth’s surface; they are home to 26 per cent of the world’s populace; and generate 32 per cent of global surface run-off (Meybeck et al. 2001). More than half the global population depends directly on mountain environments for the natural resources of water, food, power, wood, and minerals; and mountains contain high biological diversity; hence they are important in crop diversity and crop stability (Ives 1992; Smethurst 2000; UNFAO 2000). Elevation, relief, and differences in aspect make mountains excellent places to study all processes, human and physical: high energy systems make mountains some of the most inhospitable of environments for people and their livelihoods, and strikingly distinct changes in environment over short distances make mountains ideally suited to the study of earth surface processes. Mountains are often political and cultural borders, or in some cases, political, cultural, and biological islands. With ever-increasing populations placing ever-increasing environmental pressure on mountains, mountain environments are heavily impacted and are therefore quickly changing. Moreover, they are more susceptible to adverse impacts than lowlands and are degrading accordingly. Whatever environmental change or damage happens to mountain peoples and environments then moves to lower elevations, thus affecting all. Three seminal texts indicate an ongoing interest in mountain geography: the oldest, Peattie (1936), is still in print; the newest, Messerli and Ives (1997) is contemporary; and Price (1981) is now being rewritten. Indeed, mountain geography as a field in its own right has led to the recent formation of the Mountain Geography Specialty Group of the Association of American Geographers (Friend 1999). With increasing importance placed on sustainability science (Kates et al. 2001), mountain geography is at the cutting edge of inter- and multidisciplinary research that serves to unify rather than further specialize scholarly geography (Friend 1999). The United Nations proclaimed 2002 the International Year of Mountains and has devoted an entire chapter (13) of its Agenda 21 from the Rio Earth Summit to mountain sustainable development (Friend 1999; Ives and Messerli 1997; Ives et al. 1997a, b; Messerli and Ives 1997; Sène and McGuire 1997; UNFAO 1999, 2000).

In August of 1992, Hurricane Andrew battered south-eastern Florida, causing fifty-eight deaths, and more than $27 billion in property losses (National Climatic Data Center 1999). The following year, widespread flooding occurred within the Upper Mississippi River basin, inundating 5.3 million hectares during the worst flood to affect much of the region in this century. The Northridge earthquake (magnitude 6.7) led to sixty-one deaths and more than $20 billion in property damage and loss in 1994. A year later, Kobe, Japan, experienced a magnitude 6.9 earthquake. Despite massive efforts to prepare for such events, more than 6,000 lives were lost, and $150–200 billion in property damage was experienced. In 1998, Hurricane Mitch devastated Honduras, Nicaragua, and other parts of Central America. More than 5,600 people died in Honduras alone and approximately 70,000 homes were damaged. In Nicaragua, more than 850,000 people were affected, with approximately 2,860 deaths. Estimates of losses in agriculture, housing, transportation and other infrastructure are in excess of $1.3 billion dollars (United Nations Office for the Coordination of Humanitarian Affairs 1998). These are just a few, albeit particularly devastating, events that continued to focus our attention in the 1990s on hazards and disasters. The widespread news media coverage of these disaster events provided a backdrop for fictional portrayals as Hollywood rediscovered the disaster movie genre. With enhanced special effects and big-named stars, popular films such as Twister, Volcano, Dante’s Peak, Armageddon, Deep Impact, Titanic, and A Civil Action added a different slant to the media coverage of disasters and the public’s perception of hazards throughout the decade. The public’s interest and fascination in actual disasters also propelled several books to the bestseller list (Barry 1997; Junger 1997; Larson 1999). Both the fictional representations and the consequences of real disasters illustrate the shift in our understanding of the forces at work in such events. Some of the damage in Hurricane Andrew, for example, is attributed to inadequate enforcement of building standards. In Kobe, structures engineered to withstand seismic activity failed, prompting concern about just how safe infrastructure is in tectonically active areas. And Hurricane Mitch’s devastating toll cannot be explained solely by the storm. Decades of land abuse and a combination of social, political, and economic factors combined with the storm to cause the severe losses.

The idea of Canadian Studies runs counter to recent economic trends that challenge the salience of the boundary between Canada and the United States. Books such as Nine Nations of North America (Garreau 1981) declare that the boundary is an irrelevant curiosity from a bygone era. Regional boundaries are more important than national boundaries when studying the geography of North America. Canada is viewed as nothing more than the “thirteenth Federal Reserve District” of the United States (Kindleberger 1987: 16). These statements suggest that Canada is not different from the United States, so why study geography from a Canadian perspective? One response is that the study of Canada endures because scholars persist in the idea that events (and the perception of events) in Canada differ from those elsewhere in North America. This chapter emphasizes research conducted by members of the Canadian Studies Specialty Group (CSSG) of the Association of American Geographers (AAG) between the late 1980s to the present. However, where relevant, we also include research conducted by other AAG members, scholars from the Association for Canadian Studies in the United States (ACSUS), and in some cases, Canadian and other scholars who have published in American journals. While we intend to present a comprehensive survey, it is by no means exhaustive. Our goal is to identify some major themes and diverse ways that Canadian geography has been studied in the United States. The chapter examines research conducted from the late 1980s to the present, and is organized around six themes: (1) economic geography and free trade; (2) political geography of national identities; (3) urban and social geography; (4) Canada’s regions: historical and cultural perspectives; (5) physical geography; and (6) the future of Canadian Studies. The deregulation of the Canadian economy accelerated with the implementation of the Canada-United States Free Trade Agreement (FTA) in 1989 and the North American Free Trade Agreement (NAFTA) in 1994. Free trade influenced much of the recent research done on Canada’s economic geography. Prior to the FTA, Americans paid little attention to the Canadian economy (Romey 1989). The neglect stems from the lack of controversy between Canada and the United States.

History is bunk—or so Henry Ford is reputed to have said. Folk memory, though, simplifies recorded statements. What Henry Ford actually told the Chicago Tribune was ‘History is more or less bunk. It’s tradition. We don’t want tradition. We want to live in the present, and the only tradition that is worth a tinker’s damn is the history that we make today.’ So folk memory, in this case, did pretty well reflect the kernel of his views. Henry Ford also said that ‘Exercise is bunk. If you are healthy, you don’t need it; if you are sick, you shouldn’t take it.’ Henry Ford was a very powerful, very rich man of strongly expressed views. And he was quite wrong on both counts. Not having known Henry Ford, interplanetary explorers may have their own view of history. As, perhaps, an indispensable means of understanding the present and of predicting the future. As a way of deducing how the various phenomena—physical, chemical, and biological—on any planet operate. And as a means of avoiding the kind of mistake—such as resource exhaustion or intra-species war—that could terminate the ambitions of any promising and newly emerged intelligent life-form. On Earth, and everywhere else, things are as they are because they have developed that way. The history of that development must be worked out from tangible evidence: chiefly the objects and traces of past events and processes preserved on this planet itself. The surface of the Earth is no place to preserve deep history. This is in spite of—and in large part because of—the many events that have taken place on it. The surface of the future Earth, one hundred million years from now, will not have preserved evidence of contemporary human activity. One can be quite categorical about this. Whatever arrangement of oceans and continents, or whatever state of cool or warmth will exist then, the Earth’s surface will have been wiped clean of human traces. For the Earth is active. It is not just an inert mass of rock, an enormous sphere of silicates and metals to be mined by its freight of organisms, much as caterpillars chew through leaves.

This book investigates complex systems that are idealizations of naturally occurring phenomena characterized by the autonomous generation of structures and patterns at macroscopic scales. It provides material and guidance to allow the reader to learn about complexity through hands-on experimentation with complex systems with the aid of computer programs. Each chapter thus presents a simple computational model of natural complex phenomena ranging from avalanches and earthquakes to solar flares, epidemics, and ant colonies. This introductory chapter explains what complexity is, with emphasis on the fact that defining it is not a simple endeavor, and that it is not the same as randomness or chaos. It also shows that open dissipative systems are complex and clarifies what natural complexity means. Finally, it describes the computer programs listed in this book and suggests materials for further reading about complexity.

This chapter describes a simple computational idealization of a sandpile. When sand trickles slowly through your fingers, a small conical pile of sand forms below your hand. Sand avalanches of various sizes intermittently slide down the slope of the pile, which is growing both in width and in height but maintains the same slope angle. The pile of sand is a classic example of self-organized criticality. The chapter first provides an overview of the sandpile model before discussing its numerical implementation and a representative simulation involving a small 100-node lattice. It then examines the invariant power-law behavior of avalanches and the self-organized criticality of a sandpile. The chapter includes exercises and further computational explorations, along with a suggested list of materials for further reading.

This chapter considers the occurrence of traffic jams in the flow of moving automobiles as an example of complex collective behavior emerging from the interactions of system elements. It begins with a discussion of the basic design principle of an automobile traffic model and the numerical implementation of the model using the Python code. It then describes a representative simulation involving an ensemble of 300 cars initially at rest and distributed randomly, with a mean spacing of 10 units. It also examines how the traffic jam model behaves, traffic jams as avalanches, and the self-organized criticality of car traffic. The chapter includes exercises and further computational explorations, along with a suggested list of materials for further reading.