-Floods are the most frequent natural disasters, often caused by heavy rainfall orsnowmelt.
-The drought is a circumstantial or sporadic phenomenon causing a disaster.
Expand more powerful and usually last longer than other natural phenomena, so the long-term damage is greater.
-Tornadoes are storms that can reach speeds up to 500 km / hour. They moveover the continents between 200 and 500 km of latitude in both hemispheres, forming a rapid updraft of approximately 250 m in diameter. If you encountermarine waters are called waterspouts and represent a serious hazard to navigation.
-Hurricanes are violent disturbances that occur in the troposphere. Are caused bylow atmospheric pressure and rotate in a spiral around the center (eye of thehurricane). They are accompanied by very strong winds up to 300 km / h, heavy rain impressive (up to 2,000 liters per m2 in a day), embravecimiento sea and thunderstorms.
-The tsunamis have caused over the years, many disasters in coastal communities.
5.2 ¿Qué procesos naturales las originan?
-Earthquakes: Are the movements of the crust generated intense deformation in the rocks inside the Earth, building up energy is released suddenly in waves that shake the earth's surface.
-Tsunami: Movement of the crust in the ocean, forming and propagating waves of great height.
-Volcanic Eruptions: The passage of material (magma), ash and gases into the earth to the surface.
-Tsunami: Movement of the crust in the ocean, forming and propagating waves of great height.
-Volcanic Eruptions: The passage of material (magma), ash and gases into the earth to the surface.
-Landslides: The fall of a strip of land loses its stability or destruction of a structure built by man.
-Avalanche: A mass of snow moving downslope.
-Alluvium: Flows of large volumes of mud, water, ice, abrasion, caused by the rupture of a lake or a snow slide.
-Landslides: Landslides of mud and rocks due to rainfall. It comes as a blow of muddy water that slides at high speed on dry ravines and low flow dragging stonesand logs.
-Floods: slow or violent invasion of a river, ponds or lakes, due to heavy rainfall orriver breaks reservoirs, causing considerable damage. May occur slowly orgradually in plains and violent or sudden in mountainous regions of high slope.
-Droughts: deficiency of moisture in the atmosphere by precipitation river irregular or inadequate, inappropriate use of groundwater reservoirs or irrigation systems.
-Frost: Produced by low temperatures, causing damage to plants and animals.
-Storms: Atmospheric phenomena produced by electrical discharges in the atmosphere.
-Hailstorms: Precipitation of water in droplet form solid ice.
-Tornadoes: Hurricane winds that occur on a rotating at high speeds.
-Hurricane winds are in excess over 240 km / h as a result of intraction warm, moistair coming from the Pacific Ocean with the cold air.-Pests: calamities are produced in the crops by certain animals.
-Epidemics: They are the generalization of infectious diseases to a large number of people and in a certain place.
-Droughts: deficiency of moisture in the atmosphere by precipitation river irregular or inadequate, inappropriate use of groundwater reservoirs or irrigation systems.
-Frost: Produced by low temperatures, causing damage to plants and animals.
-Storms: Atmospheric phenomena produced by electrical discharges in the atmosphere.
-Hailstorms: Precipitation of water in droplet form solid ice.
-Tornadoes: Hurricane winds that occur on a rotating at high speeds.
-Hurricane winds are in excess over 240 km / h as a result of intraction warm, moistair coming from the Pacific Ocean with the cold air.-Pests: calamities are produced in the crops by certain animals.
-Epidemics: They are the generalization of infectious diseases to a large number of people and in a certain place.
5.3 ¿Cómo se distribuyen geográficamente y por qué lo hacen?
Almost all the world's volcanoes are distributed within the boundaries ofsubduction, oceanic ridges or islands arcs. The volcanic and seismic activity is developed with great intensity in areas of expansion or extension of the crust(oceanic ridges: rift oceanic and continental rift) in the areas of understanding orcollision (subduction zones) where mountain ranges are Recently, in the trenchesof island arcs, in the ocean basins (transform faults and hot spots) and in stablecontinental areas.
Hurricanes form in many regions of the world ocean. Just as there is the Atlantic Basin there are six other basins or areas where cyclones form tropicales.Sin Butthe name given to these atmospheric phenomena depends on the region in the world to form.
Tectonic earthquakes often occur in areas where the concentration of forces generated by the boundaries of tectonic plates movements result in a realignment of the interior and surface Tierra.Es why earthquakes or earthquakes of tectonic origin are closely associated with the formation of faults. Typically occur at the end of a cycle called seismic cycle, which is the time period during which deformationis accumulated inside of the Earth that later be released suddenly. Such releasecorrespond to the earthquake, after which the deformation begins to accumulatenuevamente.Se produce mainly at the edges of the plate.
5.4 ¿Pueden predecirse?
5.5 ¿Pueden prevenirse?
Volcanoes can be predicted if using temperature sensors, seismographs and samples of different materials of the craters, rocks, water and gas fumaroles (gasarising from the exterior cracks of a volcano at high temperatures). The expertsmade a detail of the particular behavior of each volcano.
Hurricanes are difficult to predict with a month in advance, are anticipatedapproximately ten days before. Using radar, satellite, radiosonde stations andNational Weather Service observatory is monitoring the arrival of the hurricane.
As for earthquakes, for the moment, forecasters have no direct way of seeingthese stresses or detecting when they reach critical levels. This, however, may be changing. The satellite-based technologies being developed at NASA andelsewhere might be able to detect signs of an impending quake days or weeksbefore it happens, by giving notice to the public and emergency preparednessservices.
Hurricanes are difficult to predict with a month in advance, are anticipatedapproximately ten days before. Using radar, satellite, radiosonde stations andNational Weather Service observatory is monitoring the arrival of the hurricane.
As for earthquakes, for the moment, forecasters have no direct way of seeingthese stresses or detecting when they reach critical levels. This, however, may be changing. The satellite-based technologies being developed at NASA andelsewhere might be able to detect signs of an impending quake days or weeksbefore it happens, by giving notice to the public and emergency preparednessservices.
5.6 ¿Hay actuaciones humanas que influyen?
From the nineties is recognized that in most cases, disasters are predictable andtherefore not as natural for man is also enhancer disasters. It is true that result fromthe occurrence of phenomena of nature such as heavy rains, landslides, earthquakes, tsunamis or hurricanes. But often, the human hand is at the origin ofthese disasters.
For example, more severe floods are powered by deforestation. An increasing share of risk is due to poor decisions in the management of development.
Besides humans pollute the planet and pollution, in turn, causes global warmingmakes the planet out of control and, therefore, disasters occur more frequently.Human intervention can also lead to natural hazards where none existed before.Volcanoes erupt periodically, but until the rich soil formed by their ejecta are notpopulated by humans, not considered dangerous. Finally, human interventionreduces the mitigating effects of natural ecosystems.
5.7 ¿Cómo reducir los efectos catastróficos de los procesos naturales?
The main fields of action, as defined by the International Strategy for Disaster Reduction (ISDR in English) include the recognition and risk assessment,knowledge development, public commitment and institutional framework, early warning systems include forecasting, dissemination of warnings, preparedness measures and improved responsiveness.
There is a clear link between the level of development and the likelihood of disaster. Therefore, poor countries and developing suffer the greatest losses of human lives as well as social and economic aspects due to their lack of resources, infrastructure and protection systems for disaster preparedness and prevention.UNESCO (United Nations Educational, Scientific and Cultural Organization) is heavily involved in promoting public awareness and education on natural disasters,two-way necessary to help the most vulnerable populations cope with these risks.
