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close this folder Chapter 3: What puts Latin America and the Caribbean at risk?
View the document Natural hazards in Latin America and the Caribbean
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View the document Risk in Latin America and the Caribbean

Chapter 3: What puts Latin America and the Caribbean at risk?

Not all violent manifestations of nature - earthquakes, volcanic eruptions, hurricanes, floods - necessarily become disasters. When a disaster does occur, it is not always the exclusive result of the nature hazard itself. What human beings do, or what they fail to do, is a key factor.

Consider the following scenario. A strong earthquake - magnitude 7.8 on the Richter scale - occurs in an unpopulated area. This violent event does not cause the loss of lives nor of infrastructure, and the country does not have to mobilize resources to respond to the situation. As a result, it is not a disaster. But an earthquake of lesser magnitude, for example 5.1 on the Richter scale, can create a disaster of major proportions if it occurs in a densely populated area, or if it causes the collapse of critical facilities such as hospitals or schools, which were not built according to code.

Consequently, the degree of risk to which a country or a population group is exposed when confronted with the effects of a violent natural phenomena depends manly on two factors: the hazard itself and the vulnerability of the exposed group.

That people have always coexisted with natural hazards is an unchanging fact.

What has changed, particularly in the last century, is the impact disasters have when they hit populated areas. In areas where there is no human population, these events for the most part do not become disasters. However, the very same natural hazard - a volcanic eruption or a tropical hurricane - can bring about very different effects depending on the vulnerability of the community.

The vulnerability of a building, a population, or a country is measured by how susceptible to harm or loss it is in the face of a hazard. Thus, the risk factor is calculated by measuring the probable occurrence of a nature hazard of certain intensity against the vulnerability of the exposed elements. For example, a building is at risk during an earthquake when

a) the earthquake (hazard) is strong enough to damage or destroy the building, and

b) seismic-resistant construction techniques are not used (vulnerability) in the design and construction of the building.

Risk is not an abstract concept; it is concrete and measurable. Many countries and communities have designed maps to illustrate their degree of risk. These maps not only mark the areas with the highest probability of occurrence of an event of certain magnitude, but also point out vulnerable infrastructure in those areas.

A natural disaster its an overwhelming ecological disturbance that exceeds the capacity of the affected community to adjust, and consequently requires external assistance.

Source: PAHO/WHO 1980.


Table 3.1 Selected natural disasters in Latin America and the Caribbean, 1970-1993.



Type of disaster

No. of reported

Estimated no. of affected people













Hurricane (Fifi)










Hurricane (David)




Dominican Republic

Hurricane (Frederick)





Hurricane (Allen)





Volcanic Eruption















Volcanic Eruption




El Salvador










Dominican Republic

Hurricane (Emily)










Hurricane (Gilbert)





Hurricane (Gilbert)





Hurricane (Joan)




Antigua, Guadeloupe, Montserrat, Puerto Rico, St. Kitts and Nevis, U.S.A., U.S. Virgin Islands

Hurricane (Hugo)









Costa Rica











Tropical Storm (Gert)



Source: PAHO/WHO: OFDA/USAID; DHA/Geneva: Atlas Nacional de Riesgos de México.


Natural hazards in Latin America and the Caribbean

Natural hazards of all types exist in Latin America and the Caribbean. The most common are classified by their origin: geological, such as earthquakes, tsunamis, volcanoes, and landslides; or hydrometeorological, such as hurricanes, tropical storms, floods, landslides, and drought. Selected natural disasters in Latin America and the Caribbean are listed in Table 3.1.

Geological hazards


During the last 100 years, earthquakes of great magnitude and intensity have rocked many countries in the Americas. Earthquake magnitude, first defined by Charles Richter, is a measure of the strength of an earthquake as calculated from records of the event made on a calibrated seismograph. The Richter scale is used to describe an earthquake's magnitude. In contrast, earthquake intensity is a measure of the effects of an earthquake on structures and the earth's surface at a specific site. Among the many existing scales, the Modified Mercalli Intensity Scale of 12 degrees, symbolized as MM, is frequently used.

Most earthquakes in the Region have been caused by the interaction of active tectonic plates (see Figure 3.1). The Cocos plate, for example, subducts or dives beneath the lighter American plate. On 19 September 1985, the Cocos plate snapped at a depth of 20 km, and seismic waves devastated Mexico City more than 350 km away. This sort of activity, the subduction and collision between the continental and the Cocos, Nazca, and Caribbean plates, is responsible for the extensive seismicity along the Pacific coast of Central and South America and in the Caribbean Basin. The earthquake that hit northern Peru on 31 May 1970 killed an estimated 67,000 people. Entire villages, such as Yungay and Ranrahirca, were buried in the avalanches and mud-slides that were triggered by the tremor. An estimated half million people were left homeless.

Figure 3.1. Map showing epicenters of earthquakes, magnitude >= 5 since 1980.

Map courtesy of NOAA, U.S. Geophysical Data Center

In Central America, the Cocos and overriding Caribbean plates are broken into distinct segments which are characterized on the earth's surface by structural depressions full of volcanic and alluvial sediments. The richness of this soil has attracted dense human settlements to spring up, precisely in those places most prone to seismic activity.

In 1972 most of Managua, the capital of Nicaragua, was destroyed by a 6.2 magnitude earthquake, leaving 10,000 dead. In 1976, 23,000 people perished in an earthquake in Guatemala; nearly 90% of the buildings in the central part of the country's high mountains were destroyed or seriously damaged. The collapse of unstable slopes, where thousands of people of limited resources lived, caused most of the deaths in Guatemala City. In March 1985 an earthquake took place in central Chile which measured 7.8 on the Richter scale with its epicenter on the coast near Alzarrobo. This event affected an area where 50% of Chile's urban population is concentrated; 180 lives were lost; 2,575 people were injured; and nearly 84,000 homes were totally destroyed. In El Salvador in 1986, a 20 square-block area in downtown San Salvador was completely destroyed, claiming more than 1,000 lives.


Tsunamis are caused by earthquakes, volcanic activity, and landslides on the sea floor which generate enormous waves. Because of the length, depth, and velocity of these waves they are difficult to detect and monitor.

About 80% of tsunamis occur in the Pacific Ocean, but there have been significant events in the Caribbean too. In 1692, 3,000 people were killed by an earthquake and tsunami at Port Royal, Jamaica. As the result of an earthquake off the Virgin Islands in 1867 and the 1918 Puerto Rico earthquake, tsunamis did extensive damage. Tsunamis present a real threat to islands that make a substantial living from tourism along their shores and for countries like Guyana and Suriname that are below sea level. One of the most serious tsunamis in recent history was one set off by the 1960 earthquake in Chile. It not only obliterated fishing villages in Chile, but caused the deaths of hundreds in Hawaii, Japan, and the Philippines. In 1992 a 7.2 magnitude earthquake off the western coast of Nicaragua generated waves over 10 m high that left 116 dead and over 40,000 homeless (see Box 3.1).


For centuries, those who have inhabited the Americas have been well aware of the hazards posed by volcanoes. Guatemala, for example, is known as the country of lakes and volcanoes, but this nickname could be applied to other countries in Central America, the Caribbean, and South America as well. As far back as colonial times, El Salvador's Izalco volcano was called the "Lighthouse of the Pacific." Yet although there are numerous active volcanoes in the Region, destructive volcanic eruptions have been less frequent than other types of natural disasters in this century.

In 1902, three major volcanoes erupted with great force in the Caribbean and in Central America. The tragedy began with the explosion of Mount Pelée in Martinique that discharged a dense emulsion of incandescent lava and boiling gases that ran downhill to the port of St. Pierre. Thirty thousand persons were suffocated. Twenty-four hours later, the Soufrière volcano on the neighboring island of Saint Vincent, 150 km away, erupted in a similar manner, causing the death of 1,500 people. Later that same year, the Santa Maria (Santiaguito) volcano in Guatemala, took the lives of 6,000 people. Three quarters of a century later, in 1979, the Soufrière exploded again, causing extensive damage and making communication impossible between the northern and southern parts of the island of Saint Vincent.

In March 1982, the Chichonal volcano in the state of Chiapas in southeast Mexico came to life with a tremendous explosion that launched a column of ash and gases 15 km high. Several days later, there was an even more violent eruption. Pyroclastic flows demolished the village of Francisco Leon and other nearby towns, damming up rivers and streams and forming lakes of boiling water. When one of these natural reservoirs opened, the banks of the Magdalena, Syula, and Grijalva rivers overflowed. An estimated 1,770 lives were lost as a result of this eruption.

After a prolonged period of inactivity, an exceptionally violent explosion of Costa Rica's Arenal volcano in 1968 launched rocks upon a nearby village, claiming 64 lives. Between 1963 and 1965 the Irazú volcano, southeast of the capital of San José, discharged such a large quantity of ash that the coffee crop and the country's economy in general were seriously affected.

Presently six volcanoes in Nicaragua - Concepción (Ometepe), Santiago, Momotombo, Pylas, Cerro Negro, and Telica - are in varying states of activity, from the emission of gases to the explosion of ash accompanied by lava flows. The eruption of the Cerro Negro volcano in 1992 spewed ash over a 200 km radius.

In South America, most of the volcanoes that erupted in past centuries were too far removed from densely populated areas to cause much havoc. However, the eruptions of Cotopaxi (Ecuador) in 1877 and Villarica (Chile) in 1936 melted large volumes of ice and snow that caused avalanches affecting vast urban and agricultural areas. The case of the Nevado del Ruiz volcano in Colombia was similar (see Box 3.2). The eruption of the Mt. Hudson volcano in southern Chile in 1991 affected some 62,000 people and caused serious damage to livestock and agriculture in Chile and Argentina.


Box 3.1


A Double Hazard in Chile. In May 1960 Chile was ravaged by a triple catastrophe - two earthquakes and a tidal wave - that affected 13 of the country's 25 provinces, leaving a profound mark on the population and causing severe deterioration in the economy. In just a few minutes, hundreds of lives were lost, dwellings were demolished, gas and water pipes broken, communications interrupted, industries destroyed, livestock lost, agriculture ruined, and roads and railroads left impassable. In several areas the topography was changed: part of the coastline sank into the sea, new islands appeared and others were demolished by the tidal wave. Three landslides covered the natural dam of Lake Riñihue, causing an avalanche that almost demolished the small towns that lay along the banks of the San Pedro River and the low lying areas of Valdivia. Chilean engineers carried out the nation's largest emergency engineering task; in two months they opened an evacuation channel from the lake, thus avoiding the destruction of a rich agricultural, livestock, and industrial area, with a population of approximately 100,000.

Source: R. Urrutia and C. Lazcano, 1993

Tumaco, Colombia. In 1979, a tsunami ravaged the Pacific coast of Colombia, destroying 80% of the important maritime and fishing port of Tumaco. The vulnerability of this area was well-known; in 1906 this city had been totally destroyed by one of the strongest tsunamis of the century. The damages were extensive because a large part of the urban area was built at sea level on loose saturated sands, which produced the phenomenon known as soil liquefaction.

Source: DHA, Geneva.

Callao, Peru. In October 1966 a magnitude 6.3 earthquake occurred off the coast of central Peru. A tsunami followed, hitting the port city of Callao in mid-afternoon, with waves that reached a height of 3.4 meters. Callao had already been destroyed once, in 1746, by an earthquake believed to have registered 8.5 on the Richter scale, that was also followed by a tidal wave that decimated the population; only 200 of the 5,000 inhabitants survived. At that time, the sea penetrated 1.5 km inland, dragging with it several ships that were anchored in the port. Eighty percent of the buildings in the neighboring city of Lima, capital of Peru, were damaged.

Source: Instituto Nacional de Defensa Civil, Peru, 1994.


Box 3.2


After almost 150 years of inactivity, the Nevado del Ruiz volcano, located 120 km northwest of Santafé de Bogota, Colombia, erupted violently on 13 November 1985. The intense heat and the seismic activity that accompanied the eruption melted only a small portion of volcano's icecap, but this was enough to send a devastating current of mud, rocks, and ashes down the riverbeds that descended its slopes, burying almost completely the city of Armero at its base.

After several days of intense search and rescue efforts, hindered because the only access to the disaster site was by air, the death toll reached 23,000. The disaster affected a 1,000 square km area in what was one of the country's most important agricultural areas. Other affected cities included Chinchiná, where 2,000 persons perished; Mariquita, where it was necessary to evacuate 20,000 people, and Guayabal. Thousands of homes, roads, and bridges were destroyed.

These mud flows, originating from volcanic eruptions, are known as lahars, and their descent can reach speeds of 100 km per hour. They occur frequently and equal or surpass the strength of incandescent avalanches, the principal cause of volcanic destruction.

In January, 1986, the volcano began again to spew toxic gasses on the affected area. Forty thousand people in a 50 km radius around the volcano had to be evacuated.

Source: PAHO/WHO: Colombian Government reports.

Hydrometeorolocical hazards


Annually some 80 cyclones - or hurricanes as they have come to be known in the Western Hemisphere from the indigenous term "Hura Kan," or "winds of the Gods" - form over warm tropical waters during the summer months. Each year it is estimated that some 20,000 people lose their lives to tropical storms worldwide; the material losses can surpass billions of dollars. The Simpson/Saffir Scale is used to categorize hurricanes (see Figure 3.2).

Figure 3.2

Between 1990 and 1992, approximately two million people in Bolivia were seriously affected by both heavy flooding and drought.

According to the OAS, between 1960 and 1989 hurricanes claimed 28,000 victims, altered the lives of another 6 million, and destroyed property valued at close to US$16 billion in the Caribbean Basin alone, without counting losses caused by those storms in Latin America, the United States, and its possessions.

More than 4,000 tropical storms have occurred in the last 500 years in the Caribbean, half of which have been become hurricanes. The most devastating of all happened in October 1780, striking practically every island in the Caribbean, beginning with Tobago, continuing through the Leeward Islands, and across Hispaniola. Almost 20,000 people perished.

An average of 10 hurricanes threaten the West Indies and the east coast of Central America and Mexico between June and November every year. In 1988 Hurricane Gilbert dealt a devastating blow to the Caribbean, leaving hundreds of thousands of people without shelter in Jamaica before cutting across the Yucatan peninsula and ravaging the Mexican city of Monterrey (see Box 3.3). Barely two months later, after striking the Caribbean coasts of Venezuela and Colombia, Hurricane Joan left a trail of destruction from coast to coast in Nicaragua and other Central American countries. The next year, Hurricane Hugo ravaged the Leeward Islands, causing serious damages in Antigua, Guadeloupe, Montserrat, Saint Kitts and Nevis, Puerto Rico and the U.S. Virgin Islands. The storm ended by slamming into the eastern coast of the United States, heavily damaging the city of Charleston, South Carolina.

In August 1992 Hurricane Andrew tore across Eleuthera and other islands in Bahamas before delivering its most forceful blow on the Atlantic and Gulf of Mexico coasts of the U.S., devastating southern Florida and, to a lesser degree, Louisiana. Property damages in the United States were estimated at US$30 billion.


Floods are, perhaps, the most frequent and among the most ruinous type of natural disaster; however, they almost never receive the same immediate attention, for example, that an earthquake or a hurricane does. Almost every country in Latin America and the Caribbean is affected by the problem of floods.

During sudden-onset natural disasters, the different stages - impact, emergency response, and rehabilitation/reconstruction - are clearly delineated. However, with slow-onset floods, the boundaries are less clear. Months can pass before the authorities realize that an emergency exists. The isolation period may be prolonged and rehabilitation or reconstruction may overlap with the next flood.

The phenomenon known as El Niño has caused cycles of heavy rains and drought in many parts of the world. The effects of El Niño in 1982-83 in South America were among the most devastating (see Box 3.4).

The principal river cities of Paraguay were affected during the winter periods of 1982, 1983, and 1987, and more than 3,000 families had to be relocated. Because of its topography, large areas of Argentina and Uruguay also experience periodic flooding.

Between 1990 and 1992, approximately two million people in Bolivia were seriously affected by both heavy flooding and drought. The floods at the beginning of 1992 in the northeast part of the country affected more than 40,000 people in 160 communities. Agricultural and livestock losses were estimated at more than US$16.6 million. The deterioration in the standard of living and the interruption of basic public health services placed the affected population at risk for outbreaks of communicable diseases.

Cuba, the Dominican Republic, Jamaica and Trinidad and Tobago are also subject to frequent flooding which impacts on the transportation sector, for example, destroying large numbers of bridges and roads. But the Caribbean is also prone to flash floods which cannot be predicted by the national meteorological offices. A number of these flash floods are the result of other hazards such as hurricanes or landslides.

The serious flooding in the Atlantic region of northern Nicaragua in May and June 1990 affected more than 100,000 people. The indigenous communities of Miskitos and Sumos, located along the Prinzapolka, Bambana, and Coco Rivers were the most affected, together with settlements in the coastal areas. The condition of the land made cultivation impossible, resulting in food shortages, which in turn, made the population more susceptible to endemic diseases in the region.

A flood's major effects on health are in four main areas: communicable diseases, environmental sanitation, food and nutrition, and vectors. As a rule, dramatic, well-defined outbreaks of diseases generally do not occur in the immediate aftermath of a flood. Instead' a slower, widespread deterioration of general health conditions takes place, which all too often becomes part of the chronic lowering of the affected community's heath status.

In areas that are continually exposed to floods, a "disaster culture" has developed over time. The people of these regions have adapted to both the frequency and difference in intensity by constructing their houses on stilts and elevating the floors with wooden boards as the flood waters rise. It is not uncommon, when water levels have reached a high point, to observe a boat tied to a window, which has become the door!


Box 3.3


At 5:00 a.m. on 9 September 1988, Jamaica's National Meteorological Service issued its first hurricane alert. Two days later, the alert had become a warning. But a majority of Jamaica's population had never experienced the direct consequences of a hurricane, and were exceedingly conservative in heeding the warning. There would he time enough in the morning to make preparations, they thought.

That was not to he the case. Only three hours of daylight remained on the afternoon the warning was issued, and during the night wind speeds accelerated. Hurricane Gilbert, a storm of colossal proportions, made landfall on the eastern end of Jamaica on September 12 at 10:00 a.m. During its trek across the island from east to west, it gathered speed and turned into a Category 5 hurricane - the most severe.

Jamaica's last experience with a hurricane was Hurricane Charlie in 1951. Hurricane Gilbert differed from Charlie in several respects. Unlike Charlie, Gilbert's eight-hour rampage crossed the entire length of the island. Gilbert was also the largest cyclonic system ever observed in the western hemisphere, and one of the wettest, although fortunately for Jamaica, most of the precipitation fell on the sea.

The impact of Hurricane Gilbert was devastating for all sectors of the society and the economy. Damage was estimated at US$4 trillion, with the damage to agriculture accounting for over 40% of this total. Ninety-five percent of all health facilities suffered damage. Of the 25 public hospitals only two escaped with minimal damages. Two were destroyed and eleven suffered severe damage. There are 377 Health Centers in the island and 55% of these were severely damaged. The cost of emergency repairs was estimated at US$13 million with roughly 55% of this representing the cost of repairs to secondary care facilities.

The National Water Commission managed the storage and distribution of domestic water. The hurricane damaged over 50% of these facilities to a degree which varied from minor to complete destruction. Pipelines, storage tanks, pump and chlorinator houses were all affected. There were instances in which rivers changed their courses, threatening supplies and facilities.

The response from the international community was immediate and large quantities of supplies flooded the country. Daily meetings were held to coordinate donor response and the needs of the country. This achieved some measure of success. However, it was felt that prearranged needs lists would have speeded up the process of acquiring necessary supplies. Moreover, the major part of the relief effort centered around the transportation of goods. The cost of mobilizing distribution was, at times, greater than the value of the goods. A great deal of time was also spent in clearing, documenting and sorting the donations.

Source: PAHO/WHO

Box 3.4

El Niño

In June 1982, scientists again began to observe a series of atmospheric and oceanic changes in the region of the equatorial Pacific, which were related to the phenomenon known as El Niño. This phenomenon causes floods and droughts at irregular intervals of between 3 and 16 years along the western coast of South America, as well as in many other areas of the world. This 1982 occurrence of El Niño caused widespread drought in western Bolivia, southern Peru, northeastern Brazil, Costa Rica, southern Mexico, Indonesia, the Philippines, Australia, New Guinea, parts of Africa, southern India, and southern China. It also caused floods in Ecuador, Peru, eastern Bolivia, southern Brazil, northern Argentina, eastern Paraguay, and the Polynesian islands.

In the housing sector in Peru, the urban slums in Lima were the most affected by this phenomenon. In total, 62,771 dwellings were partially damaged or destroyed by flooding. The transportation and drinking water and sewerage infrastructure were practically destroyed. The floods ruptured water and sewerage networks, causing severe shortages of services to most of Peru's coastal population, including the city of Piura, where 16,750 meters of pipe were destroyed.

The consequences of El Niño along the coast of Ecuador caused the country's marine reserves to virtually disappear, severely damaging the fishing industry. In addition, heavy rainfall in these coastal areas reached into the mountains in some parts. causing rivers to overflow.

Source: PAHO/WHO.



Drought is a phenomenon that has affected large areas of the Western Hemisphere, but perhaps the case whose causes and effects have been most studied is that of Brazil. Since the 1940s, an increase in the population, the large scale destruction of natural resources, and growing desertification have caused this country to suffer increasingly severe droughts. These periodic droughts destabilize the primitive economy of the region, deplete the natural resources, burn the grasses, decimate livestock, and demolish crops, converting the sertão into a desert landscape whose inhabitants, deprived of reserves, die from lack of food and water. Many migrate to the large cities, where they add to the growing number who inhabit the favelas, or slums circling the cities.

The effects of drought, always disastrous, grow in proportion to the extent of the territory affected. If the affected area is not very large, neighboring regions that are not affected can offer aid. According to the Brazilian author Luis Augusto da Silva Vieira, in his account of drought in northeast Brazil in the first half of this century, the crises occur in irregular patterns: partial drought usually occurs every 4 to 5 years, normal drought, every 10 to 11 years, and exceptionally severe cases are seen every 50 years. The great drought of the 1980s verified this, since the two previous large-scale droughts had occurred in 1X77 and 1932.


The impact of landslides depends on the specific nature of the event and its origins. For example, landslide failures of hillsides or mountain slopes obviously constitute a hazard to human beings and property; but in general cause damage in only a limited geographic area. By contrast, volcanic-triggered slides, avalanches, mudflows and lateral blasts can affect larger areas and can cause greater life and property loss. The large majority of landslides are caused or intensified by geologic and hydrometeorologic factors. The case of Armero, Colombia, in 1985, demonstrated one of the most destructive consequences of a volcanic eruption: volcanic mudflows descended from the summit of Nevado del Ruiz at great speeds following the paths of several rivers in the area.

However, the most severe landslides are those caused by the gradual displacement of large areas of the earth's surface, since their effect on buildings and other infrastructure is slow but dangerous. This type of landslide is triggered by extreme hydrometeorological conditions or by earthquake shaking.

Road and highway construction can cause slope failures: limited budgets often dictate where and at what angle a slope is cut rather than what is most stable. When severe rains occur, the roads collapse, not only claiming lives and interrupting important lines of communication but also placing severe demands on the limited institutional resources available to rebuild them.

Human activity, particularly deforestation of watersheds, pollution, and other impacts can result in landslides with extreme economic and social impacts. A landslide dam on the Paute River in Ecuador flooded most of the fertile land upriver of the slide. Population centers downriver were threatened by the catastrophic failure of the landslide dam (see Box 3.5).

Landslides caused by strong rains and flooding have had devastating effects in the Region, particularly in deforested areas and in areas where housing has been constructed on unstable soils. One tragic failure occurred in the Bolivian goldmining camp of Llipi, north of the capital city, La Paz. Torrential rains on 8 December 1992 caused a landslide that buried the entire village; 49 people were killed. Deforestation contributed significantly to the disaster; tunnels used for mining collapsed. A similar landslide occurred in Ecuador in May 1993, in the goldmining region of Nambija, claiming 140 lives.

In early August 1993, Tropical Storm Bret raced through the eastern Caribbean, causing severe structural damage in Trinidad and Tobago before striking Caracas, Venezuela, with full intensity. The storm's rains and winds triggered landslides in poor neighborhoods located in the outskirts of the capital and in the States of Miranda and Aragua. At least 100 people died, 400 were injured, and approximately 5,000 were left homeless.


Box 3.5


Medellín, Colombia. September 1987 a major landslide estimated to contain 20,000 cubic meters of earth descended on the neighborhood of Villatina in the city of Medellín, Colombia. An uncovered open channel, located in the upper part of the neighborhood, which had deteriorated because of a lack of maintenance, overflowed and added to the mass, destroying 100 dwellings, killing 207, leaving 300 missing, and nearly 2,000 affected. The Villatina neighborhood was located in an appropriate area for urbanization, given the topographical conditions and was not thought to be susceptible to such hazards.

Source: Bustamante, 1987.

Rio de Janeiro, Brazil. In February 1988 a strong cold Arctic air mass passed over southern Brazil, triggering torrential rains in the state of Rio de Janeiro and depositing 279 cubic millimeters of rain on the city of Rio de Janeiro and neighboring areas. The rains caused rivers to overflow and flooded the poorer neighborhoods that surround the city, destroying hospital and dwellings and leaving 289 dead, 734 injured, and 18,560 affected. The drinking water services, sewerage, electric energy and telephones were interrupted for several days. The direct cause of the landslides was the rainwater that saturated the steep slopes of unstable soil and insufficient drainage for the large volume of water.


La Josefina, Cuenca-Ecuador. In March 1993 a landslide containing 20 million cubic meters of earth blocked the Paute River with a dam of rubble and dirt 100 meters high and one kilometer long, causing a reservoir of 200 million cubic meters of water to form upstream from the blockage. Warning had been given about this hazard, but measures needed to avoid the disaster had not been taken. It occurred because of heavy rainfall at the site of a previous landslide, and was brought on as well by inadequate road construction.

Following the landslide, a channel was constructed to drain water from behind the blockage, thereby reducing the flooded area upstream. But 26 days after the original landslide, the drainage channel itself collapsed, and due to the erosion brought on by continua rains, the dam fared one week later. This failure resulted in flash floods damaging an area that extended 100 km below the dam. Although inhabitants in the floodplain had been evacuated, a tote of 35 people lost their lives, and economic losses were estimated at US$ 140 million.

The flooding and impending dam collapse threatened the Paute Hydraulic Project, located 50 km downstream! which provides 65% of Ecuador's power. The dam failure was simulated so that contingency plans could be prepared for that occurrence.

Source: Zevallos, 1994


A close relation exists between vulnerability to disasters and socioeconomic development. For example, the accelerated rate of urbanization in Latin America contributes to its vulnerability, and also leads to environmental degradation and to poverty, which in turn lead to the use of inadequate construction techniques. Other factors such as population growth and low levels of education are related closely to the problem of vulnerability.

The Accelerated Rate of Urbanization

Most developing countries worldwide have witnessed a rapid rate of growth in their urban population, while in developed countries, it has declined. This growth is not only due to birth rates, but to the trend to migrate from rural to urban areas, especially among population groups of limited resources that look to the cities for better access to services and greater sources of income. The result is often the creation of perilously situated settlements on the fringes of large urban areas.


Natural disasters in Latin America and the Caribbean have invariably shown that those with lime income and a poor quality of housing suffer disproportionately when disaster strikes. The poor, with lower levels of education, often live in improvised settlements in highly vulnerable locations, such as the slums on the landslide-prone hills of Rio de Janeiro, the slopes of volcanoes, or riverbanks. During periods of drought, the most affected are those who cannot acquire food. Most often, hunger results from a lack of money to purchase food rather than from the lack of food itself. Poverty is also the greatest cause of both internal and international migration, which poses serious challenges in terms of immediate assistance, as well as in long-term development efforts.

A study by UNDRO (1988) estimated that 95% of the deaths caused by disasters occurred among 66% of the population of the world's poorer countries. In Japan, for example, an average of 63 per sons die each year because of natural disasters. In Peru, a country with a similar incidence of disasters, the toll is 2,900.

Latin America and the Caribbean share a problem common to many parts of the world: not only do the poor receive a disproportionate share of the impact of the disaster itself, but they also are at a disadvantage during the rehabilitation and reconstruction phases. Prior to a disaster, this group depends on their limited income, often generated at home, for their daily survival. A disaster not only robs them of their source of income, but they cannot absorb the additional expense of purchasing materials for reconstruction. This accelerates the poverty cycle, which, in turn, heightens vulnerability to disasters.

Vulnerability of Constructions

The type of construction, as well as population density in the areas of greatest hazard, increase vulnerability. It is estimated that almost 90% of the victims of earthquakes are injured by the collapse of buildings, as was the case in Nicaragua in 1972 and in Guatemala in 1976. A similar situation occurred in Dominica in 1979 and Montserrat in 1989, where an estimated 90% of the housing that collapsed was due to non-compliance with hurricane or wind-resistant codes.

Most old constructions in Latin America, both housing and institutions, are made of adobe and unreinforced masonry. Adobe houses do not resist earthquakes in the same way as wood structures, which are lighter and more flexible. The weight of the clay tile roofs of many of these structures also contributes to their instability, as was the case in the earthquake of Guatemala, where many died as a result of collapsed buildings.

To a great extent in the Region, the infrastructure of basic services such as water and energy is old, and many countries lack the resources to maintain it properly. Weak infrastructure poses a great obstacle to providing uninterrupted services. In times of disaster, hospitals and educational facilities, which over decades have undergone structural modifications without taking into account safety considerations, put already vulnerable groups - children, the sick, and the poor - at greater risk.

Environmental Factors

The environment surrounding human settlements contributes to disasters. In some cases, these surroundings cannot be modified and people must learn to adapt to avoid the serious consequences inherent to the location. For example, soil type is a determining factor as to why earthquakes cause more damage in some places than in others. The earthquake of 1985 in Mexico had its epicenter off the coast of the state of Guerrero, 350 km to the southwest of Mexico City. The coastal city closest to the epicenter, Acapulco, suffered only minor damages, but the capital was devastated. Mexico City was constructed on the site of the ancient Aztec capital of Tenochitlán. Over the centuries, the lake which surrounded the Aztec capital as a moat had shrunk, leaving deep layers of clay, sand, and gravel beneath the surface. Unlike solid rock, Mexico City's soil transmitted seismic waves as rocking motions, similar to ocean swells, which many edifices could not withstand (see Box 3.6).

In other cases, man's attempts to modify his surroundings contribute to disaster situations. Deforestation, environmental degradation, and the irrational use of land create precarious conditions that multiply the effects of disasters. For example, deforestation leads to water runoff which contributes to flooding and landslides; the destruction of mangroves reduces the ability of coastal regions to resist tropical winds and high waves.

The use of advanced technology in commercial agricultural production can be harmful. When machines are used to farm fertile areas of a country, the rural labor force loses its source of employment and has no recourse but to move R. more marginal areas.

Drought conditions often are exacerbated by inadequate growing patterns, excess of pasture lands, indiscriminate exploitation of natural resources, deforestation, or inappropriate land conservation techniques. Deforestation in Haiti, due partially to the exportation of fine woods, and to the lack of fuel, contributed to drought conditions in this country. In Latin America, approximately one fifth of the territory is threatened by desertification, which can leave in its wake social unrest, conflicts, and mass migrations, in addition to hunger and disease.


Box 3.6


An earthquake of extraordinary magnitude, 8.1 on the Richter scale, caused extensive damage in a densely populated area of downtown Mexico City on 19 September 1985. The earthquake and its aftershocks caused the deaths of more than 10,000 persons; tens of thousands were injured and left homeless.

Approximately 33,600 dwellings were destroyed and 65,000 more suffered considerable damage. The health sector facilities were especially hard hit, with many hospitals and clinics destroyed. Nearly one fifth of the schools in the city were destroyed or seriously damaged. Also seriously damaged or destroyed were the water, electrical, and telecommunications systems in the central city.

The direct losses were estimated at $US3.8 billion. These losses included the urban infrastructure, public service facilities and their equipment, housing, heath and educational facilities, communications, small industry and businesses. The indirect losses were estimated at $US544 million and included the decrease of income and the increase in costs to small industry and business, communications, tourism, and the personal services sector. The total losses caused by the earthquake amounted to $US4.4 billion, making this natural disaster one of the most damaging in recent years in the Region.

More serious than the absolute losses is the effect which the rehabilitation and reconstruction had on the macro economics of Mexico. The effects are especially significant considering that the total losses represented only 2.7% of the GDP of Mexico. However, the disaster occurred at a time when the government was applying a policy of austerity in public expenditures; thus, banks had limited assets to meet the increased demand for credit and more external restrictions were foreseen. In the five years following the earthquake, the negative effect in the balance of payments reached US$ 8.6 billion in spite of considerable income from insurance and foreign donations. The fiscal deficit increased approximately $US 1.9 billion due to the expenses of rehabilitation and reconstruction.

The demands of the reconstruction required the Mexican authorities to revise their economic policy to accommodate greater needs for public funding, credits, and imports. The priorities for public expenditures were reoriented to reconstruction projects leaving many of the pre-disaster problems of the city unattended.

Source: Jovel, ECLAC, 1985. Reprinted from Disasters and Development. UNDP/UNDRO. 1991

The relationship between disaster and development

Nations increase their capacities and decrease their vulnerabilities through development. Development planning is used by governments to draft plans to guide economic and social development. The concept of sustainable development is widely recognized by international agencies and by governments, although its definition is not universally agreed upon. Sustainable development is the outcome of comprehensive planning that incorporates considerations of disaster risk (reducing hazards and vulnerability) as well as strategies designed to protect the environment and to improve economic growth, levels of education, and living conditions of the entire population (see Box 3.7).


Box 3.7



Disasters can provide unique windows of opportunity in development. In the wake of the 1986 earthquake in El Salvador, the health sector took advantage of the severe damage to the large Children's Hospital to restructure and decentralize services so that the nation would not be dependent on the services of one "megahospital."

Disasters +

The El Salvador earthquake also had extreme social and developmental consequences: scarcity of housing, high unemployment (26-35%), and a reduced capacity in public health facilities. Hurricane Joan, which ravaged the Atlantic coast of Nicaragua in 1988, also had serious effects on an already failing economy during a difficult political and economic period.

Disasters -


Housing or infrastructure projects built in accordance with construction safety codes are less vulnerable because they have been designed to better withstand disaster impact. Research into construction of adobe dwellings in Peru, for example, aims to improve the performance of old and new dwellings in future seismic events.

Development +

Activities related to development projects - such as quarrying for construction materials or indiscriminate clearing of forests for agricultural purposes - can degrade soil conditions, thereby increasing the risk of disasters. Other projects designed as income-generating opportunities can accelerate urban growth and force lowincome workers to seek housing in marginal, hazardprone areas.

Development -

Source: PAHO/WHO: IDNDR Regional Office.


Economic losses caused by a disaster of great magnitude often exceed the annual gross income of a country It is not surprising then that these events can paralyze the affected countries and cause social and political disturbances. The World Bank has estimated that in developing countries, the economic losses due to disasters, as percentages of the gross domestic product (GDP), are 20 times higher than in industrialized countries.

According to the Economic Commission for Latin America and the Caribbean (ECLAC), disasters have three types of economic repercussions: direct effects on property; indirect effects caused by losses in economic production and services; and secondary effects that are manifested after the disaster in a reduced national revenue, increased inflation, problems of foreign trade, increased public spending, the resulting fiscal deficit, and reduced monetary reserves.

Table 3.2 presents estimated economic losses caused by selected natural disasters in Latin America and the Caribbean. Although these losses are not devastating for industrialized countries with strong economies, they have serious and lasting effects on the susceptible economies of developing countries. For example, drought and floods in Bolivia, Ecuador, and Peru associated with El Niño reduced the per capital income by 10% and elevated some retail food prices by 50%. Although the direct losses caused by the Mexico earthquake were equivalent to only 2.7% of the GDP, the expenditures for reconstruction and rehabilitation of basic services wreaked havoc on the economy, at a time when Mexico was operating under a policy of fiscal austerity.



(in millions of 1987 US dollars)a




Floods/ droughts

Losses & effects

Mexico City


David & Frederick

El Niño






Total losses





Direct losses





Capital stock















Indirect losses















Secondary effects


Public sector finances





Increased expenditures





Decrease in revenues





External sector





Reduction of exports





Increase in imports





Disaster-related income





a All figures adjusted for inflation through 1987 to enhance comparability.

b Secondary effects estimated for 1986 to 1987, and projected thereafter through 1990.

c Includes damages caused by ensuing floods and mudflows which represent a very high percentage of the total.

d Damages refer to the Dominican Republic only, even though other countries were affected as well.

e Damages refer to Bolivia, Ecuador and Peru, although other countries were affected as well.

f Figures in parentheses refer to income gained from insurance and foreign donations.

g Produced significant increases in the fiscal deficit; exact figures are not available.

Source: Jovel, 1989. Reprinted from Disasters and Development, UNDP/UNDRO, 1991.


Risk in Latin America and the Caribbean

While risk is concrete and measurable, it is also relative and depends on how communities view it. People constantly attempt to diminish their vulnerability to hazards, while at the same time maintaining a balance between the risk and the benefits attached to. them. For example, living near a volcano presents the threat of an eruption, but provides the advantage of fertile lands for agriculture.

Calculating to make risks measurable makes them seem controllable. But it is one thing for planners to calculate risks and another for people to accept the calculations, want to act on them, and then have the means to do so. Many families who live in areas prone to the periodic flooding of rivers rebuild their dwellings on the same sites while awaiting the food, clothing, and building materials from agencies in charge of the emergency response. Planners view this risk of living on the river bank as unacceptable; for them, the idea solution is to relocate these people. But the people themselves are attached to familiar areas, may be more afraid of unknown hazards than familiar ones, and may insist on staying.

In Latin America and the Caribbean, important relationships exist between natural hazards, the particular vulnerability of each community or population group, and the risks each faces of suffering the effects of disaster. To convince people that they should take steps to become less vulnerable, and then give them a way to overcome the risk, is the vision of all who work in the field of disaster reduction.

To convince people that they should take steps to become less vulnerable, and then give them a way to over-come the risk is the vision of all who work in the field of disaster reduction.