Natural disaster # Desastres naturales

PRESENTATION
Institute:
Teacher:
Student:
Topic: Final Paper on Natural Disaster
Year:
Date: November 2003
Town:
INDEX
• Introduction ___________________________________page 3
• Peril and catastrophe___________________________page 4
• Alternative of prevention________________________page 5
• Floods__________________________________________page 6
• Glaciar floods___________________________________page 7
• Floods control__________________________________page 7
• Earthquake_____________________________________page 8
• Prediction of earthquake________________________page 9
• Type of earthquake______________________________page 10
• Drougth________________________________________page 11
• Dryland farming_________________________________page 12
• Cyclones________________________________________page 13
• Volcanos________________________________________page 14
• Tornado_________________________________________page 16
• Datum__________________________________________page 18
• Conclusión______________________________________page 19
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• Bibliography_____________________________________page 21
INTRODUCTION
I was doubtful, and did not know what to write about in my final paper.
One day I spoke with my teacher; she suggested that I could write about natural disasters.
Then I realised that it was an interesting topic, because the people have to be prepared in one catastrophe, as
they are in danger, because the catastrophes are natural disasters .
In a catastrophe the people act in different ways, produce different answers, this depends on the type of
information and the motivation of each sector.
The quantity of victims, numbers of death and material damage give us an idea of scale of the catastrophe.
It's a very interesting topic because there were and there are population that suffer from this, and the natural
disasters are a phenomenon of nature.
PERIL AND CATASTROPHE
The natural media that sustains the human beings presents an equilibrium that is not continuous, but when it
suffers alteration, that manifests suddenly and unexpectedly, natural catastrophe, to the natural phenomenon,
that takes place in the environment, whose consequences alter the physical, social and economic order.
The natural catastrophes are classified according to how the terrestrial area are affected.
Sphere of the earth
Natural peril
Floods
Hydrosphere
Droughts
Seaquakes
Volcanism
Lithosphere
Earthquake
Earth movement
Tropical cyclone
Atmosphere
Tornado
Plague
Biosphere
Forestall fire
The peril is the possibility that a certain territory suffers the consequences of a natural devastating and
anomalous process.
Before this catastrophe, the people act in different ways, produce different answers, this depends on the type
of information and the motivation of each sector, for example: the population may be don't know about it or
maybe they deny it.
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The scientists study this phenomena with great dedication and involve themselves in the study of the location,
measuring and classification, while the institutions plan the actions to reduce the peril and it's effects.
The quantity of victims, numbers of deaths and material damage give us a idea of the scale of the catastrophe,
but we must also take into account, that the effects in economics are so ample that it's difficult to quantify
them.
In the last year the power of destruction of natural disaster is caused by human actions, such as conditions of
growing demography, occupation of zone of peril, urbanization, degradation of environment and poverty, etc.
According to some scientists it isn't possible to avoid catastrophe, but we must be prepared, it's necessary to
have scientific and technologic knowledge and most important of all is the cooperation, solidary in all sectors
of the society.
ALTERNATIVE OF PREVENTION
The effect of catastrophe depends on the natural media where it occurs, the intensity of the catastrophe and the
answer of the society that is involved.
The following hints describe general alternatives about how a catastrophe could be prevented
• Identification of peril zone and palming of the use of the soil according to this.
• Implementation of warming systems, energy measure and contraction laws.
• Use of information programmes and interchange of knowledge.
• Matainance of appropriate sanitary conditions, as if there
is a catastrophe, it is a danger for the population health and arisk because illnesses transmitted by water could
appear.
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FLOODS
Floods occur when the water of river takes or streams overflow their banks and pour out onto the surrounding
land.
Mainly in spring of the year, the amount of water in river and streams rises to a higher level than usual, and
the excess spills over the banks, cause little damage.
Floods are caused by many different things:
If the land is hard and rocky, the water can't be absorbed.
If the ground is frozen, the rain is unable to sink into the hard earth.
Floods do not occur every spring in all mountain areas. Much depends on the amount of the snow of the snow
and the of the melting process.
The discharge volume of an individual stream is often highly variable of this variability is the flash floods,
unexpected torrent of muddy and turbulent water rushing down a canyon or gulch. It is uncommon, of
relatively brief duration, and generally the result of summer thunderstorms in mountain.
GLACIER FLOODS
This can be spectacular of even catastrophe. These happen when drainage within a glacier is blocked by
internal plastic flow and
water is stored in or behind the glacier. The water eventually finds a narrow path to tricked out. This
movement will cause the path to be enlarged by melting, causing faster flow, more melting, a larger conduit
and so on until all the water is released quite suddenly.
Outburst floods occur in many glacier covered mountain ranges, some breakout regularly each year, some are
completely irregular and impossible to predict.
FLOODS CONTROL
Man was never able to prevent floods completely. But he can do a great deal to control floods lesend the
damage they cause.
The two great causes of floods are too much rain and the slope of the land toward the river. Little can be done
to eliminate these causes. All man science can't enable him to change the weather and prevent rainfall. All is
engineering skill can't completely change the slope of large land areas.
The people have found ways to lessen the damage caused by floods. One method is to plants trees on the slope
lands, these tree help the soil to absorb and retain more rain cuales.
River channels can be deepened and even the paths of river can be changed. Then, cubed evident storms or
melting spokes pour huge quantities of waters into the river, the excess can often be carned off be new and
deeper channels.
EARTHQUAKE
Any sudden disturbance within the Earth manifested at the surface by a shaking of the ground. This shaking,
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which accounts for the destructiveness of an earthquake, is caused by the passage of elastic waves through the
Earth's rocks.
Over the centuries they have been responsible for millions of deaths and an incalculable amount of damage to
property. While earthquakes have inspired dread and superstitious awe since ancient
times, little was understood about them until the emergence of
seismology at the beginning of the 20th century.
PREDICCTION OF EARTHQUAKE
Generally, periodicities in time and space for major earthquakes have not been widely detected or accepted.
One problem is that earthquake catalogs are not homogeneous in their selection and reporting. The catalog
contains some information about 1,000 destructive earthquakes. The sizes of these earthquakes have been
assessed from the reports of damage, intensity, and shaking.
Usually correlations are made between the physical phenomena assumed to provide the trigger and the
repetition of earthquakes.
No trigger mechanism, has been found that satisfies the various criteria necessary to establish a clear physical
connection.
Statistical methods also have been tried with populations of regional earthquakes. It has been suggested that
the slope of the regression line between the number of earthquakes and the magnitude, mentioned in the
previous section, for a region may change characteristically with time.
For prediction of the time of earthquake occurrence, a proposal is that precursory changes in a region will
cause the velocity of seismic waves through the region to change.
For many years prediction research has been influenced by the basic argument that strain accumulates in the
rock masses in the vicinity of a fault and results in crustal deformation. Deformations have been measured in
the horizontal direction along active faults and in the vertical direction by precise levelling and tiltmeters.
Some investigators believe that changes in groundwater level occur prior to earthquakes; variations of this sort
have been reported mainly from China. It should be noted that water levels in wells respond to a complex
array of factors such as rainfall; thus, if changes in water level are to be studied in relation to earthquakes,
such factors need to be removed.
For earthquake prediction, the significance of dilatancy is its effects on various measurable quantities of the
Earth's crust, such as seismic velocities, electric resistively, and ground and water levels. The consequences of
dilatancy for earthquake prediction are summarized in the Table earthquake: physical clues for prediction.
The rise of pore pressure also has the effect of weakening the rock and enhancing fault slip. Strain buildup in
the focal region may have significant effects on other observable properties, including electrical conductivity
and gas concentration. Because the electrical
conductivity of rocks depends largely on interconnected water channels within the rocks, resistivity may
increase before the cracks become saturated. As pore fluid is expelled from the closing cracks, the local water
table would rise and concentrations of gases such as radioactive radon would increase.
Less well−grounded precursory phenomena, particularly earthquake lights and animal behaviour, sometimes
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draw more public attention than those discussed above. Many reports of unusual lights in the sky and
abnormal animal behaviour preceding earthquakes are known to seismologists, mostly in anecdotal form.
TYPE OF EARTHQUAKES
Earthquakes are caused by the sudden release of energy within some limited region of the rocks of the Earth,
the release of elastic strain energy is the most important, since this form of energy is the only kind that is
stored in sufficient quantity in the Earth to produce major earthquakes.
Tectonic earthquakes occurs when stresses in rock masses have accumulated to a point where they exceed
the strength of the rocks. These rock fractures usually tend in the same direction and may extend over many
kilometres along the zone of weakness.
Volcanic earthquake , it is likely that even here the energy released may be the result of a relatively sudden
slip of rock masses
and the consequent release of elastic strain energy. The energy, may in part be of hydrodynamic origin due to
the motion of magma in reservoirs beneath the volcano or to the release of gas under pressure. In the rupture,
the rock masses spring back to a position where the elastic strain is less. This movement at any point may not
take place at once but rather in irregular steps.
The irregular properties of fault rupture are now included in the modelling of earthquake sources, both
physically and mathematically. Fault rupture starts at the earthquake focus and propagates unilaterally or
bilaterally over the fault plane until stopped or slowed at a barrier.
Earthquakes have different properties depending, that causes them. The geological interpretation of a fault is
given in terms of standard geometries. The usual fault model has a strike (direction from north of the
horizontal line in the fault plane) and a dip (angle between direction of steepest slope and horizontal).
For a homogeneous Earth, one curve is in the plane containing For a homogeneous Earth, one curve is in the
plane containing, that passes through the focus and is perpendicular to the forces of the plane. For the actual
Earth, the nodal curves are displaced from these locations because of the curvature of the wave paths between
focus and surface.
DROUGTH
Lack or insufficiency of rain for an extended period that causes a considerable hydrologic (water) imbalance
and, consequently, water shortages, crop damage, stream flow reduction, and depletion of groundwater and
soil moisture. It occurs when evaporation and transpiration exceed precipitation for a considerable period.
Drought is the most serious physical hazard to agriculture in nearly every part of the world.
There are four basic kinds of drought:
• Permanent drought characterizes the driest climates; the sparse vegetation is adapted to aridity, and
agriculture is impossible continuous irrigation.
• Seasonal drought occurs in climates that have well−defined annual rainy and dry seasons.
• Unpredictable drought involves an abnormal rainfall failure; it may occur almost anywhere but is
most characteristic of humid and sub humid climates is irregular it affects small area.
• Invisible drought can also be recognized: in summer, when high temperatures induce high rates of
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evaporation and transpiration.
DRYLAND FARMING
The cultivation of crops without irrigation in regions of limited moisture, typically less than50 centimetres of
precipitation annually.
Dry farming depends upon efficient storage of the limited moisture in the soil and the selection of crops and
growing methods that make the best use of this moisture. Moisture control during crop growing consists
largely of destruction of weeds and prevention of runoff. The ideal soil surface is free of weeds but has
enough clods or dead vegetable matter to hinder runoff and prevent erosion.
There have been many severe droughts, and there is a natural tendency for lay observers to view these as
manifestations of the greenhouse effect, several formulations of which predict drought in mid−latitude areas.
Although this is a possibility, most authorities agree that the droughts and other fluctuations are expressions of
climate's natural internal variability and not of externally forced change.
CICLONES
Cyclonic winds move across nearly all regions of the Earth except the equatorial belt and are generally
associated with rain or snow. Also occurring in much the same areas are anticyclones, wind systems that
rotate about a high−pressure centre. Anticyclones are so called because they have a flow opposite to that of
cyclones spiralling motion, with the winds rotating clockwise in the Northern Hemisphere and counter
clockwise in the Southern.
Cyclones occur chiefly in the midlatitude belts of both hemispheres
In the Southern Hemisphere cyclones are distributed in a relatively uniform manner through various
longitudes.
In the Northern Hemisphere continental landmasses extend from the Equator to the Arctic, and large
mountain belts interfere with the midlatitude air currents, giving rise to significant variations in the occurrence
of cyclones ,and anticyclones, certain tracks are
favoured by the wind systems.
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Cyclones that form closer to the Equator differ somewhat in character from the extratropical variety. Such
wind systems, known as tropical cyclones, are much smaller in diameter.
In the Atlantic and Caribbean regions, tropical cyclones are commonly called hurricanes, while in the western
Pacific and China Sea the term typhoon is applied.
Extratropical cyclones: are the most abundant and exert influence on the broadest scale, affecting the largest
percentage of the Earth's surface, this class of cyclones is the principle cause of day−to−day weather changes
experienced in middle and high latitudes and thus is the focal point of much of modern weather forecasting.
VOLCANOS
Is the name given to the processes and phenomena associated with the surficial discharge of such material
from volcanoes, geysers, and fumaroles. Volcanoes figure prominently in the mythology of many peoples
who have learned to live with eruptions, but science was late in recognizing the important role of volcanism in
the evolution of the Earth.
Geologists today agree that volcanism is a profound process resulting from the thermal evolution of planetary
bodies.
Volcanoes are the surface manifestation of this thermal process, which has its roots deep inside the Earth and
which hurls its ashes high into the atmosphere. The term volcano can either mean the vent from which magma
erupts to the surface, or it can refer to the landform created by the solidified lava and fragmental volcanic
debris that accumulate near the vent.
Volcanoes, are not the realm of any single scientific discipline. Rather, they require study by many scientists
from several specialties: geophysicists and geochemists to probe the deep roots of volcanoes; geologists to
decipher prehistoric volcanic activity; biologists to learn how life becomes established and evolves on barren
volcanic islands; and meteorologists to determine the effects of volcanic dust and gases on the atmosphere,
weather, and climate.
This affect humankind in many ways. Their destructiveness is awesome, but the risk involved can be reduced
by assessing volcanic hazards and forecasting volcanic eruptions. Volcanism provides fertile soils, valuable
mineral deposits, and geothermal energy. Over geologic time volcanoes recycle the Earth's hydrosphere and
atmosphere, and explosive eruptions can affect climate.
TORNADO
When a tornado forms or passes over a water surface, it is called a waterspout.The name tornado comes from
the Spanish tronada, which supposedly was derived from the Latin tornare. The most violent of atmospheric
storms, a tornado is a powerful vortex,
or "twister," whose rotational speeds are estimated to be close to 480 kilometres per hour but may
occasionally exceed 800 kilometres per hour.
The first visible indication of tornado development is usually a funnel cloud, which extends downward from
the cumulonimbus cloud of a severe thunderstorm.
Tornadoes often occur in groups, and several twisters sometimes descend from the same cloud base. The
forward speed of an individual tornado is normally 48 to 64 kilometres per hour but may range from nearly
zero to 112 kilometres per hour.
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Although much remains to be learned about tornado formation and movement, remarkable advances have
been made in the effectiveness of tornado detection and warning systems. These systems involve analyses of
surface and upper−air weather, detection and tracking of atmosphere changes by radar, and spotting severe
local storms.
Intensity of the tornado
scale
Velocity km/hours
0
From 65 to 115
consequence
Fracture the branch of the tree.
Prejudicial posters and antenna.
Unfast cover of roofs.
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From 116 to 180
Displace vehicle.
Unfast top.
2
From 181 to 250
Root out tree.
Upset vehicle.
Roof out removes trees from root.
3
From 251 to 330
Destroy houses.
Elevate vehicle.
Generates rocky objects of big size.
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From 331 to 420
5
From 421 or more
Takes off tree trunks that keep standing.
Damages structures of reinforced cement.
DATUM
• The biggest natural disasters happened in the earth during 1963_1992, were the floods that caused the
greatest number of material damage and dearth of people; folowed by tropical ciclones, droughts and
earthquakes.
• In the year 1993 about 70 disasters we recorded in different cantries an
_ In Central América there were floods, tropical cyclones, epidemies, volcanic eruption and earth movements.
_ Andes América had epidemies, earthquakes and earth movement.
_ Africa had floods, earthquakes and epidemies.
_ SE asia had tropical cyclones,floods,volcanic eruption, earth movement, tornado and hailstorm.
_ SO Asia had floods, earthquake and earth movements.
Natural disasters happen in the last year
1992
Huracane Andrés in florida_ EEUU
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1993
1994
1995
1997
1997
1997
1997
1998
1998
1998
1998
1998
2002
2003
2003
Floods in the Mississippi_EEUU
Earthquakes in Los Andes _EEUU
Earthquakes in Jaalisco_ México
Tornado in Itaqui _ Brazil
Huracane Paulina in Acapulco_ México
Eerth movement in Mendoza_ Argentina
Eathquakes in Asis_ Italia
Earthquake in totora_ Bolivia
Drought in Parnamburgo_ Brazil
Floods in La Cuenca del Plata
Huracane Mitch in centroamérica
Maremoto in Papúa _Nueva Ginea
Huracane in California_ EEUU
Floods in Santa Fe _ Argentina
Forest Faires in Córdoba_ Argentina
CONCLUSION
I thought about this topic for my final paper, because it's very interesting, I know the damage that natural
cause.
Moreover, in the last year the power of destructed of natural disasters are caused by human action, this causes
problems, as humans aren't worried about supporting the environment in good conditions.
There are a lot of natural disasters, but I chose:
• Floods: are caused by many different things for example: if the land is hard and rocky, the water can't
be absorbed; if the ground is frozen, the rain is unable to sink into the earth.
The two causes the floods are to much rain and the slope of the land .
• Earthquakes: are cause by the sadder released of energy with in some limited region of the rocks of
the earth. For prediction of the time of earthquakes occurrence, a proporsal is that precursory changes
in a region will caused the velocity of seismic wave through the region to change.
• Drought: there are for basic king of drought: Permanent drought, Seasonal drought, Unpredictable
drought and invisible drought. There have been many severe droughts, and there is natural tendency
for lay observes to view these as manifestation of the greenhouse effect
• Cyclones: the principal cyclone tracks over the ocean, this surface being smoother than that of the
lands and thus offering less resistance to the strong winds around low−pressure centres.
• Volcanoes: this affects human kind in many ways because provides fertile sals, valuable mineral yhe
posits and geothermal energy. Geologists today agree that volcanism is a profound presses resulting
from the thermal evolution of planetary bodies.
• Tornado: often occurs in groups, and several twisters sometimes descend from the same cloud base,
the direction of motion is usually from the southwest to the northeast.
This catastrophe aren't the only phenomenon that act agamst the nature.
These final paper is very interesting because it taught me the causes that produce natural disasters.
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Moreover. I learnt the cause that brings about the catastrophe, the type there are in some phenomenon, and as
the population act agamest the natural phenomenon.
Finally, I can say that natural phenomena are a terrible catastrophe, that keeps the population in danger.
BIBLIOGRAPHY
• Enciclopedia Británca
• Enciclopedia Encarta 2003
• Internet
• La sociedades y los espacios geográficos_ Argentina
• Dictionary
• Atlas geográfico universal y de la Argentina
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