Abstract: The alpine treeline ecotone in Glacier National Park (GNP) can respond to climate change An examination of what is known about treelines in general indicates that seedling establishment is the important response to climate change, but this stage is also affected by many other variables In GNP, the importance of protected sites generated by local geomorphic processes is closely connected to microclimate Once seedlings are established, positive feedback is generated and tree species can advance rapidly Feedback creates nonlinear relations in the response of vegetation to climate and so decouples the response to climate at least in rate Then protected sites can become fully occupied during periods of rapid response driven by feedback but less available immediately thereafter even if the climate continues to ameliorate The response that we see in GNP indicates that specific conditions in time and space – the historically contingent and the local – can outweigh generalities about ecotones

Abstract: Throughout the twentieth century, Brazilian agriculture was responsible for rapid occupation of territory, especially because of two major crops that were characteristic of the most important agricultural frontiers The coffee culture was predominant in Brazil during the first half of the century This crop greatly influenced the country’s national and international economic standing That period was called the Brazilian coffee cycle, most notably in the south and southeast, where pedoclimatic and geomorphological conditions were more appropriate However, during the second half of the century, soy and cattle-raising became major factors influencing the expansion of Brazilian agriculture and the incorporation of new areas to the territory, specifically in the savanna region This expansion was the result of prevailing morphopedological conditions and the new technologies brought about by advances in agronomic research linked to soil correction, fertilization, and irrigation Subsequent hydropedological imbalances have accelerated erosive water dissection of the relief and the consequent production of sediments, responsible for silting valley floors, reservoirs, and drainage channels These problems are frequently caused or promoted by the intense and indiscriminate deforestation taking place, in the case of coffee, on large expanses of the Mata Atlântica (Atlantic Forest), and in the case of soy, in the savanna

Abstract: This chapter reviews the status of knowledge on landslides in Argentina in order to understand their behavior and their implications for landscape evolution. This basic understanding allows an analysis of both the vulnerability of mountain communities and the potential risk for regional society and economies. Slope instability processes are analyzed as related to the Argentinean geological provinces. The main landslide processes throughout Argentina and detailed events that have occurred in each region of the country are reported. Landslides are widespread in Argentina. The most catastrophic events have been described for mountain regions, which comprise one-third of the country, extending from the north to the south border, involving mountains, ranges, tablelands, and sea-cliffs. Atypical rainstorms and seismic events affecting geological structures and weathered rocks are identified as the main landslides triggering forces in Argentina. Winter precipitation caused by the westerlies generate landslides, together with fall and flux mechanisms. Overaccumulation of snow and fast melting of snows during exceptionally warm spring days cause avalanches and debris flows. Landsliding triggered by earthquakes can occur all along the Andes, especially in the central and northern geological units. Volcanic activity promotes lahar formations. Over the Patagonian tablelands, landsliding is initiated mainly by fluvial undercutting after heavy summer storms, wave erosion at the footslopes, or groundwater-level variations. Snow avalanches and mudflows seem to be climatically conditioned in specific regions, while the other processes have a wide distribution. Antropic activities such as slope urbanization, irrigation, roads development, ski centers as well as exotic fauna that block and affect mountain rivers should also be considered landslide-triggering factors.

Abstract: Peru is a land of contrasts, with natural hazards occurring in coastal deserts, high Andean mountains, and humid Amazon lowlands. Increasingly, however, population growth exposes more people to risks as cities spread and as land use must intensify. These social features interact with a heterogeneous distribution of seismic risks shaped by the way the Nazca plate subducts, causing earthquakes to occur throughout the mountains and on the coast, with active volcanoes in the south. Landscapes are shaped not only by catastrophic events such as landslides, but also by soil erosion and fluvial transport. In Peru, rains and floods during an El Nino year can rearrange surface features, in addition to destroying houses and infrastructure. Even if people perceive, recognize, and acknowledge the presence of risks from these natural hazards, they are often constrained in the way they can or will respond. Vulnerabilities in Peru to natural hazards are amplified by poverty and by a disconnection between what science can predict and what people will do.

Abstract: Mountains provide vital ecosystem services to humans, such as freshwater supplies from melting snow; better understandings are needed of the processes and dynamics that control mountain ecosystems, especially the alpine treeline ecotone (ATE). As one of America’s cherished national parks, Glacier National Park in the northern Rocky Mountains of Montana presents a challenge to managers because it is already responding to recent climatic change and, with continued climatic change, may be altered in ways that will diminish its ecological and social value. At present, one third of the park is above treeline but the ATE is moving upward which will, among other things, lead to impacts on winter snowpack accumulations. This will, in turn, impact lower elevation biota through essential changes in mountain hydrology. Snow avalanche paths may become more stabilized through new tree growth, changing disturbance patters, and other geomorphic processes, such as mass movement and soil forming processes will respond to changes in ATE structure and spatial extent as well. The ATE is thus a high-priority research topic because of ecological importance, interest to Park managers, and possible role as a climate change signal.

Abstract: Geomorphic patterns and processes affect alpine treeline at a variety of spatial and temporal scales. At coarse scales, snow avalanches and debris flows are widespread and create disturbance treelines elevationally depressed well below the climate-controlled alpine treeline. At medium scales, turf-banked terraces create tread-and-riser topography that is a difficult landscape for a tree seedling to survive upon because of exposure to wind, dryness, and impenetrable surfaces. At fine scales, turf exfoliation of the fronts of turf-banked risers, and boulders, offer microsites where tree seedlings may find shelter and are able to gain a foothold in the alpine tundra; conversely, however, surfaces of needle-ice pans and frost heaving associated with miniature patterned ground production are associated with sites inimicable to seedling establishment or survival. The geomorphic role of animals at treeline may assist or hinder seedling survival.

Abstract: Notwithstanding the wide variety of definitions of the term disaster (Westgate and O’Keefe, 1976), it is evident that in areas such as Mexico and Central America (M&CA), high levels of risk are controlled by the combination of hazards and vulnerability. Clearly, the character of the landscape plays a major role in the occurrence of natural hazards, given that mountain terrains occupy large extensions of land subjected to tectonic and volcanic activity, and surface processes take place driven by tropical climate. Furthermore, the social, economic, political, and cultural conditions of populations determine their vulnerability to those hazards. Different analyses concerning the impact of disasters associated with natural hazards suggest that the number of fatalities is greater in developing countries. At the global scale, consequences also point toward a trend in which the number of disasters has increased, whereas the number of fatalities is decreasing, but the number of affected people and economic losses are increasing to a major extent. Latin America, and especially Central America and Mexico, are not the exception. Therefore, in order to have a better understanding of the impact of disasters in this region, this chapter seeks to provide general insights into the spatial and temporal dimensions of disaster occurrence in M&CA in the course of about a century. Data analysis indicates that during the period between 1902 and 2007, 465 disasters associated with natural hazards occurred in the region of interest. Droughts, earthquakes, floods, mass-movement processes, storms, and volcanic eruptions that took place in highly vulnerable communities caused more than 160,000 fatalities and involved a total affected population of about 32 million. Estimated damages amounted to US$43,109,000,000.

Abstract: Some of the most important consequences of global climate change (GCC) are rising mean annual or seasonal temperature, rising or diminishing precipitation at the regional level, rising global sea level, and increasing frequency of extreme meteorological events. The impact of these changes has been observed in the glaciers and permafrost areas of South America, particularly the Andean ranges, Patagonia, Tierra del Fuego, and the Antarctic Peninsula at least since 1978 and, particularly in the last decade of the twentieth century. The most noticeable impacts are the fast glacier margin recession, thinning of the ice cover, elevation of the regional snowline, and the reduction of Andean areas under permafrost conditions, as recent scientific research has demonstrated. Small mountain glaciers and ice caps are vanishing all over the Andean ranges, from Venezuela to Tierra del Fuego. At the present rate of ice recession, most, if not all of the cirque glaciers in Patagonia and Tierra del Fuego will disappear during the next two decades, and both valley glaciers and the Patagonian ice sheets will be severely reduced as well. Ice barrier collapse in the Antarctic Peninsula will provide a larger supply of large icebergs which will jeopardize navigation routes, increasing sailing risks in the southern seas, with at least two iceberg-cruiser impacts in the 2007–2008 austral summer. As a consequence of snowline rising and glacier vanishing, damage on environmental, hydrological, geomorphological, heritage, and tourism resources is expected to affect these regions and those communities active in them.

Abstract: Bolivia is a large and diverse nation in its geography, its culture, and its economy. Poverty levels are high throughout the nation, with a large part of the population having only limited access to essential services, including education, health, and sound housing. In 2007, Bolivia was ranked 117th out of 177 countries on the Human Development Index, a standardized measure combining life expectancy, literacy, education, and overall standard of living (UNDP, 2007). This is the third lowest index in the Western Hemisphere. Because of these socioeconomic conditions, Bolivia is highly vulnerable to hazards, both natural and man-made. The political, economic, and physical geography of Bolivia has been thoroughly reviewed by Montes de Oca (1997) . Although Bolivia is in a tectonically and volcanically active region, neither seismic nor volcanic events have historically produced as large an impact (measured by total loss of life or livelihood) as have hydrometeorological events, including floods, landslides, droughts, and frost. Climate change is predicted to increase future temperatures in all parts of the nation, further accelerating the loss of mountain glaciers and snowpack and exacerbating the impact of drought in semiarid agricultural regions. Predictions of future precipitation changes vary according to the particular climate model, but the most robust result points to a possible increase in the intensity of wet-season precipitation (more wet days per year) over large parts of Amazonia and southern South America (IPCC, 2007, p. 896). The latter would increase the flooding hazard of much of lowland Bolivia that has already been subjected to widespread flooding for the past three years (2006–2008).

Abstract: The pattern of conifer establishment and the potential role of positive plant interactions in tree islands at alpine treeline are examined at three treeline locations in Glacier National Park. Tree island development is often initiated by the establishment of a conifer near a microtopographic shelter source, and subsequent establishment creates a linear, series-like pattern in the lee of previously established trees. First-order Markov analysis of series pattern of established individuals in tree islands demonstrates relative stability or self-perpetuation of many of the early-established individuals, lowering the number of predominant vegetation classes. Embedded Markov analysis, however, suggests that the establishment of conifers within a patch does not follow a predictable spatial sequence; however, Pinus albicaulis , a foundation and keystone species, occupies sites immediately behind shelters more than other species and therefore may facilitate subsequent conifer establishment. The spatial patterns of these treeline series are highly variable with study sites, as would be expected from the highly variable local environments of these sites and a largely structural facilitation regime. Where species richness and patch dynamism is high, there may be greater potential for treeline advance on a coarse scale than there is at sites with low species richness. Low richness sites may be more susceptible to stochastic disturbance events that would disrupt conifer establishment and survival.

Abstract: Latin America and the Caribbean region have experienced numerous destructive earthquakes. Earthquakes represent one of the main causes of massive casualties and economic loss due mainly to the proximity of populated areas to plate boundaries and other dynamic parts of the Earth’s crust. Seismic ruptures related to shallow earthquakes ( Earth–surface deformation during an earthquake is concentrated at the epicentral region where the most important damage usually takes place. This coseismic deformation is related to the faults and folds linked at depth with the primary seismic sources. Part of these fault lines lie offshore, related to subduction zones and other major plate interaction features. However, many earthquake-related structures are located in continental areas. The surface deformation related to historic and prehistoric earthquakes allows their recognition and analysis in terms of the significance and characteristics of past earthquakes and the probability for future ones. These faults and folds can be regarded as potential seismogenic sources, highlighted sometimes by active seismicity and/or historic records of destructive earthquakes. However, many potentially active structures show no evidence of historic or instrumental seismicity. For those cases, gathering data with a time frame larger than the one provided by seismic catalogues is crucial for a proper seismic hazard assessment. Therefore terrain analysis and geomorphologic techniques are considered to be a primary tool for providing basic information in the seismic hazard evaluation of a specific structure or region. This chapter examines, through some examples, the contribution of the geomorphologic analysis to the evaluation of geological structures considered to be hazardous seismogenic sources in Latin America and the Caribbean.

Abstract: Because most of its territory is located in tropical and equatorial areas, climatic factors are a main driver of natural disasters in Latin America For instance, intense tropical rainfall in mountain areas is responsible for some of the most catastrophic floods and landslides in Latin America, such as those that occur in northern Venezuela, Colombia, and southeastern Brazil The El Nino-Southern Oscillation also triggers a variety of geomorphologic hazards along the continent such as the floods, landslides, and coastal erosion that affect desert areas of the Pacific coast and the floods and landslides that affect southeastern Brazil and the La Plata Basin In Central America and Mexico, hurricane landfalls from the Eastern Pacific and Atlantic Ocean bring intense rainfall, winds, and storm surges that cause devastating floods and landslides Many of the devastating effects of natural hazards and disasters have been aggravated by increased human-induced vulnerability in various Latin American regions Human-induced desertification in Patagonia and accelerated fluvial erosion in south and southeastern Brazil are examples of negative human effects on the Latin American landscape that aggravate the effects of natural disasters Climatic trends in South America during the last few decades, in particular in the Argentinean plains, have also contributed to flood aggravation

Abstract: Research for evaluation of geologic hazards, especially seismic and volcanic, have generally received little attention in Argentina Nevertheless, the relatively small work done up to the present indicates that a vast field of research has to be developed, not only from the viewpoint of the potential occurrence of an earthquake with destructive force on Argentine territory, but also from the perspective of the Neogene tectonic architecture Earthquakes with magnitudes higher than Ms > 6 are numerous in the Argentine territory Even though these events have been analyzed, mostly in the central western provinces of Argentina, their effects have been underestimated in the northwestern and southern regions Since the urban centers in the Argentine western and southern provinces have not experienced an explosive growth in recent years, it is advisable to recommend setting up plans for reducing hazards, based on restrictions in the use of land in undeveloped areas and following standards established for the construction of infrastructure This type of planning will yield the best strategies for reducing the economic impact of eventual seismic and/or volcanic phenomena The present chapter analyzes some evidence of Quaternary faulting considered to be potential seismogenic sources, as well as the main destructive earthquakes that have occurred in Argentina The types of Quaternary volcanic eruptions are described, and a preliminary estimation is made of the hazard presented by the presence of active and potentially active volcanic centers in the arc and backarc environments of the country

Abstract: Alpine tundra soils and soils formed under krummholz in our study area differ little in key characteristics including effective soil depth, differences in compaction, horizonation, or profile development indices. Soils at these sites may be significantly older (i.e., late Pleistocene) and are more well developed than has been reported in the literature. Soil compaction at turf-exfoliated sites was the only soil-related variable varying spatially at a scale associated with tree seedling establishment in alpine tundra.

Abstract: Spatial biotic positive feedback, that is, where trees improve microclimatic conditions for other trees, can influence ecotone patterns and processes. We examined the effects of positive feedback between pattern and tree establishment using computer simulation models validated against a dendrochronological reconstruction of subalpine forest advancement on Lee Ridge in Glacier National Park. We used a hybrid simulation that combines physiologically mechanistic and forest-stand models to represent multispecies interactions between spatial pattern and process, mechanistic responses of tree growth to climate, and changing environmental and vegetative conditions. Feedback was incorporated into the model as an increase in site quality due to microclimatic amelioration by upwind neighbors, primarily through snow deposition. The model was able to produce observed forest advancement rates and patterns, but did not adequately predict stand basal area or density, probably due to unrealistic mortality rates and competition for light. The results suggest that feedback is an important process controlling vegetation patterns and dynamics at treeline ecotones that may affect their sensitivity to climate change. Treeline ecotones in changing environments exhibit unique growth and mortality characteristics, as well as changes in the relative importance of endogenous and exogenous controls that must be incorporated into simulations of their dynamics.

Abstract: The active geology of Ecuador, as volcanic, tectonic, and plutonic conditions interact in the tropical landscape, makes up for the country’s high propensity to disaster In this chapter, the anthropogenic impact of landscape change is highlighted to contribute to a better understanding of what seems to be the catastrophe-prone existence of Ecuadorian villages and cities inserted into the capricious topography of the Tropical Andes Changing the forest cover for pasture and agriculture has left many mountain areas unprotected against erosion, biodiversity loss, massive migrations, and overall farmscape transformation Construction of mega-projects in the higher watersheds, along with road networks that defy gravity in the slope lands, are indicated as direct triggers of an explicit human driver of landscape change With a review of the major calamities that Ecuador has suffered related to geomorphologic forces, and the implications of the lack of planning and preparedness, the lax social responses are also criticized for the risk transfer inconsistencies in disaster management of an increased number of low-intensity and ephemeral events in Ecuador

Abstract: Krummholz and patch forest vegetation are studied at several sites on the east side of the Continental Divide in Glacier National Park, Montana, USA. The location of each sampled krummholz patch was collected as well as species information and a number of patch geometry measurements. Additionally, the Leaf Area Index (LAI) was derived for each patch using a LI-COR LAI-2000 plant canopy analyzer. The patch geometry information was used to create 3D models of each krummholz patch that, in turn, were used to derive two additional canopy structure variables, foliage density (FD) and drip-line LAI (DLLAI). Correlations were calculated among the canopy structure variables, patch position variables, landscape position variables, and biophysical variables. Results suggest (a) a complex internal patch organization of krummholz forest patches with respect to canopy structure, (b) canopy distribution strongly related to the slope position of the patch, and (c) a pronounced relationship between canopy structure, soil moisture potential, and landforms.

Abstract: South American coasts are subject to many different natural hazards. In general terms, the Pacific coast is tectonic, and therefore, earthquakes and tsunamis are likely to occur in this area. The Caribbean coast is constantly subject to trade winds and episodically to hurricanes and tsunami-triggered waves. The Atlantic coasts of Brazil, Uruguay, and Argentina suffer the action of storm surges coming from the south (southeasterlies). At the same time, the South American coast is particularly exposed to El Nino-Southern Oscillation (ENSO)-triggered effects. These effects are different in different regions. In Colombia the seasonal increase of the mean sea level alters the dynamics of barrier islands. In Peru, ENSOs are responsible for sudden inputs of sediments to the coast; similar processes impact the estuarine complexes of Lagoa dos Patos (southern Brazil) or Parana-Rio de la Plata floods (Argentina–Uruguay). In northern Brazil, on the other hand, dry conditions induce the migration of dunes landward. In several countries of South America, population is concentrated at or near the coast, and therefore some natural coastal processes increase their impacts. In recent years, erosion effects have been more severe due to the action of humanity.

Abstract: This chapter presents a review of the seismic history and context of Venezuela. The largest cities of the country are located along a narrow seismic belt between the Andes and the Caribbean Sea that concentrate to threaten >80% of the Venezuelan population. Long periods between destructive earthquakes have contributed to a false feeling of stability in society. During the last decades the main cities have been growing rapidly and chaotically, at the same time that vulnerability has increased because of the occupation of risky areas, the scarcity of seismic-resistant constructions, and consistent disregard of norms and rules relating to construction and urban planning.

Abstract: Geospatial data and spatial digital technologies, with an emphasis on remote sensing, geographic information systems, global positioning systems, spatial analysis, and modeling, have been fundamental to the research conducted by the Mountain GeoDynamics Research Group in Glacier National Park, Montana, USA. Applications of GIScience tools and techniques have varied according to the research questions being examined and the corresponding analytical designs imposed. Most of our studies have been conducted at the landscape and regional levels, relying, for instance, on (a) historical and contemporary panchromatic and natural- and false-color aerial photography, (b) aircraft and satellite multispectral digital data, (c) spatial coordinates secured from differentially corrected GPS units and processed using base-station files, (d) field electronics and spatial designs, (e) a GIS to integrate discrete, continuous, and multithematic data, and (f) statistical and process models to associate field and lab data for the alpine and subalpine environments. Selected analyses are described that have advanced our understanding of pattern–process relationships at the alpine and subalpine environments, as a consequence of the spatial, spectral, radiometric, and temporal resolutions of the remote sensing system employed and the image processing approaches followed. Our work with digital elevation models is also described, because of the complex topography in the Park and the sensitivity of ecological and geomorphic features to terrain settings. Finally, our emphasis of linking patterns to processes is described through the use of pattern metrics, scale-dependent analysis, multisystem remote sensing, and integrative models.

Abstract: Colombia’s mountain regions are densely populated, and their geological, climatic, and geographic characteristics imply not only very variegated landscapes but also exposure to many risks of natural origin: earthquakes, volcanic activity, torrential floods, floods, and landslides. Seven examples of recent events were selected to illustrate the magnitude that these phenomena, often of complex character, may reach. A volcanic eruption with deadly lahars, three earthquakes with enormous secondary effects, and three cases of complex processes related to heavy rainfall are briefly discussed. It may be concluded that a country so exposed to natural disasters should maintain an up-to-date inventory and permanent monitoring of natural processes, research on natural phenomena, and improved geomorphological mapping. These activities should be completed by educational programs and inclusion of natural restrictions in regional and local planning and land-use regulations.

Abstract: Publisher Summary Floods in South America, affect only a minor proportion of the population because the risky areas are sparsely populated. Nonetheless, these floods generate socioeconomic catastrophes relating to production losses in agriculture and cattle farming. Because of their location in the Andes chain and the Circum-Pacific ring of fire, countries such as Guatemala, Nicaragua, Mexico, Costa Rica, El Salvador, Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina are susceptible to earthquakes and volcanic eruptions. A natural disaster can be defined as the product of an extreme relationship between physical phenomena and a society's structure and organization. The concept of a regional environmental vulnerability implies evaluating the area's susceptibility or resistance to disasters that may be caused by natural phenomena. It is a fact that environmental vulnerability must be taken into account in all future regional, national, and local activities. The vulnerability of Latin American societies to natural disasters is high because of inadequate public policies. In general terms, all the Latin American countries have poorly developed management strategies for handling natural disasters. Public policies and laws seem to be insufficient to guarantee disaster prevention and mitigation because of the political instability in several of the Latin American countries. This factor has also contributed to a poor implementation of long-term and sustained national or regional programs on disasters, and low respect by legal fulfillment.

Abstract: The future of treeline in Glacier National Park is discussed and shown to be one of change This change has not occurred in a vacuum separate from other natural processes but rather is one of several forms of change documenting the effects of climate change in the Park The treeline of the future will look substantially different than that currently observed in our study area

Abstract: Turf-banked terraces in the alpine tundra of Glacier National Park, Montana, are typically characterized by alternating stripes of flat, stone-covered treads or steps and angled risers covered by alpine tundra vegetation. Previous research has suggested that the presence of turf-banked terraces is controlled by local environmental settings, particularly, topographic conditions. In this research, regression analysis is used to assess the correlations between turf-banked terrace characteristics and a set of hypothesized environmental controls. Measures of turf-banked terraces include the widths and standard deviations of treads, risers, and all stripes measured at 55 areally distributed 50-m field transects; the ratio of riser width to tread width; and a set of four one-dimensional pattern metrics that assess the spatial structure of the tread/riser sequences. These measures were derived using a run-length approach for field transects distributed in basins located throughout the eastern side of the Continental Divide. The environmental variables, generated from a 10-m spatial resolution digital elevation model (DEM), include elevation, slope angle, slope aspect, slope curvature, and soil moisture potential. Our results show that several turf-banked terrace characteristics are significantly correlated with individual environmental variables; stronger relationships are found when turf-banked terrace characteristics are related to transformed (i.e., principal components analysis) environmental variables using multiple regression analysis.

Abstract: Landslide conditions and problems involve functional relationships among natural elements (climate, topography, rocks, soil, vegetation and fauna) and artificial elements (related to land use) of the landscape, which may change over space and time. Two characteristic rainfall regimes might express rainfall–landslide relationships in southern and southeastern Brazil: less intense events of longer duration tend to favor deep rotational failures along channel banks and road cuts, colluvium-deposit creep in valley bottoms, and shallow translation failures on steep lands; extreme rainfall events tend to favor shallow translational slides and debris flows on steep lands, block-rich debris avalanches along main valley bottons and rock falls on vertical scarps. Landslide disasters are commonly associated with less frequent, intense, and spatially nonuniform rainfall events during the summer rainy periods. Critical events have prevailed along the highly populated coastal region, especially in the upper portion of steep mountain slopes. In this text the authors draw special attention to case studies of historical landslide disasters in the most populated area of Rio de Janeiro State, and also include some other case studies in southeastern and southern Brazil.

Abstract: Because of Chile’s location in the southwestern part of South America, its geological and geomorphological evolution has been controlled by the subduction of the Nazca and Antarctic plates beneath the South American Plate at the Chile-Peru Trench. As a result of this dynamic situation, Chile presents numerous natural hazards, including earthquakes, tsunamis, volcanism, and landslides. The country also has a significant vulnerability and risk because many cities, some of them with large populations, are located in high-hazard zones. In view of this situation, the active participation of different administrations is needed to implement actions aimed at reducing the country’s vulnerability and risk. These actions should include detailed geological, microseismological, and geomorphologic studies (which in Chile are not required) in order to provide better assessment of hazards; elaboration of exposure, vulnerability and risk maps; incorporation of such studies into land-use planning; surveillance, early warning, and alarm systems for the different hazards; and educational programs to increase the population’s awareness and improve its preparedness to face hazards. Those actions should provide the basis for establishing plans for disaster prevention and mitigation.

Abstract: Desertification in the extra-Andean region of Patagonia is the most significant environmental problem in this area, due both to its severity and to the area it covers. This region, defined as the geographical region east of the Andean Range in the southernmost portion of the American continent, covers an area of approximately 550,000 km2, between 36˚ and 56˚ south latitude. The region is characterized by arid and semiarid climate. Precipitation decreases abruptly from west to east. Annual rainfall in almost the whole extra Andean Patagonia territory amounts to less than 250 mm, with absolute values below 100 mm in the central region. Arid environmental conditions also increase, with permanent strong winds from the west and southwest blowing across the region, which are more intense in spring and summer and thus favor evaporation. These climatic conditions determine dominant steppe vegetation in extra-Andean Patagonia. The relief is dominated by plateaus composed of friable sedimentary rocks, partially covered by Cenozoic basalt flows. Environmental conditions notably influence land use in Patagonia. The main economic activities are based on the exploitation of the natural resources, mainly livestock production, hydrocarbons, and tourism. Livestock production, especially sheep, started by the end of the nineteenth century with the settlement of wool growers in different areas of the plateau. In a few decades sheep stock increased rapidly from 1,790,000 head in 1895 to more than 25,000,000 head in 1952. That excessive grazing pressure caused plant and soil degradation. Moreover, shrub removal for fuel production for family use at first, but also as an alternative source of income, such as supply for cookers, heaters, and boilers for mining, oil, and railroad camps, military bases, or towns, contributed to the clearing of extensive areas. Since 1960, the development of mining and hydrocarbon activities in the region has contributed to an increased level of environmental degradation, which was also increased by the explosive growth of petroleum activities in the 1990s. The clearing of lands with the aim of generating spaces for the establishment of petroleum locations and the wide network of roads that communicate them has resulted in important areas of bare soil that are exposed to wind erosion, rain, and surface runoff. In these areas, “deflation tongues” are generated, which constitute one of the most active aeolian forms in Patagonia. At present, the whole extra-Andean Patagonia territory exhibits a diverse degree of desertification. This degradation is explicitly evidenced in biophysical components of the ecosystem, but it also has social and economic consequences. Since the mid-twentieth century, together with these degradation processes, the livestock number has gradually decreased, jobs have been lost, and there has been a migratory movement of rural populations into urban centers.

Abstract: In Venezuela, more than 50% of the population lives in the coastal-mountain region because most of the country’s economic activities are concentrated in these areas Presently, hundreds of thousands of people live in very vulnerable sites, and it seems impossible to avoid potential catastrophe, especially in the poorest neighborhoods, which are located in intermountain areas of the main valleys and in the foothills of the northern Caribbean Mountains In these areas, urban expansion since 1950 can be traced very clearly, as the result of population growth close to the center of the main economic activities This chapter analyzes some of the most remarkable disasters that have recently affected Venezuela The impacts of disorganized urban growth on alluvial fans and the catastrophic flood on the north face of the Caribbean Mountains of Venezuela are presented here in historical perspective Because of the magnitude of the event, details are offered on the disaster in 1999 at Vargas, which killed more than 15,000 people as a result of debris flows on the coastal alluvial fans The torrential avalanche of the Limon River in the south side of the north central Caribbean Mountains and other recent human and natural disasters caused by catastrophic floods in the Venezuelan Andes are discussed On the basis of all the disasters we have reviewed, we can conclude that the catastrophes were induced mainly by human mistakes produced by poverty and by the lack of governmental policies on territorial planning of new urban zoning Urban expansion was undertaken without taking into account the natural dynamics of the geomorphic systems

Abstract: Argentina is a country strongly affected by floods; the main areas affected and the disasters produced by such floods are discussed herein. The fluvial systems of Argentina can be classified into three main groups: large tropical rivers, torrential rivers with headwaters in mountain areas, and flat-plain rivers with insufficient drainage efficiency. The torrential rivers group can be subdivided into two categories: (a) Rivers fed by torrential rains, and (b) rivers fed by rain and snow. Agriculture and cattle farming have been the main activities of the national economy since the origin of the nation, and these activities are concentrated in the Chaco-Pampean region, an extremely flat area with very productive land but poor drainage capacity. Floods in rivers such as the Salado (Buenos Aires Province) and local floods in the Sub-Mmeridional lowlands of Santa Fe affect thousands of inhabitants and millions of hectares of productive land, causing huge economic losses of up to more than US$ 500 million. The Parana River is the country’s largest tropical river and its main waterway. Several important cities are located along its banks. Some of the largest floods on the Parana River have been related to El Nino-ENSO events. During the 1982-1983 El Nino-Enso event, more than 234,000 people had to be evacuated, and damage caused losses of more than US$ 2,600 million. The floods of the 1991-1992 El Nino-ENSO event were also catastrophic, causing estimated losses of US$ 513 million and affecting more than 122,000 inhabitants.. Floods also affect some of the inhabitants of Patagonia and urban centers in the Piedmont areas of the Andes in the northwest region of the country, although the number of people affected and economic losses are lower that those in the Pampa and Parana River regions because of their low population densities and less developed regional economies. One particular case, the flood of the city of Santa Fe in 2003, one of the most dramatic natural catastrophes in Argentina, is also analyzed. The disaster was produced by a combination of intense rain in the lower basin of the Salado River (Santa Fe) and the negligence of the local government. Nearly 140,000 inhabitants were affected, and the flood caused an economic loss of around US$ 1,000 million. It is argued that two main factors have contributed to generating the worst scenario for disasters in Argentina: a climatic trend, since approximately 1970, of increasing rainfall, and the political instability of the country throughout practically the whole of the second half of the twentieth century until the present day.