Earthquake
Earthquake
often happens around us. It brings great damages. Earthquake is hard to be
predicted and that makes lot victims. Actually there are three kinds of earthquake. This kinds of earthquake are
commonly base on the factor and geological area where the earthquakes happen.
These three kinds of earthquake are tectonic, volcanic and explosion. Tectonic earthquakes is most common one. This kind of earthquake happens while
earth's crust rocks break because of the geological strength created by moving
of the earth's plates. Volcanic
earthquakes happen exactly with volcanic activity. Volcanic earthquakes are
when the volcano produces acidic lava, which drys quickly, when it drys quickly
it blocks the top of the volcano. This make no more magma can escape. Pressure
starts to build up and eventually the acidic lava can no longer stand the
pressure. So the volcano is free to explode, the pressure is released so fast
that an earthquake is caused. A volcanic earthquake is usually kept within
10-20 miles of the volcano. Explosion earthquakes are the result of the collapse earthquakes that are small
earthquakes occurring in underground mines and caverns.
Mangrove
Trees
A mangrove is a tropical marine tree. Mangroves
have special aerial roots and salt-filtering tap roots which enable them to
thrive in brackish water. Brackish water is salty but not as salty as sea
water. Mangrove trees are commonly planted and found in coastal areas.
Mangroves can serve as walls of protection for natural disaster in coastal area
like tsunami.
According to BBC News,
healthy mangrove forests had helped save lives in the Asia disaster tsunami and
people tended to respect these natural barriers even more, especially after the
tsunami. There are several species of mangrove tree found all over the world. Some
prefer more salinity, while others like to be very-close to a large fresh water
source such as river. Some prefer areas that are sheltered from waves. Some
species have their roots covered with sea water every day during high tide.
Other species grow on dry land but are still part of the ecosystem. The Times of
India reported that rare species of mangrove had been found and was
also known as the looking-glass tree, probably because the leaves are
silver-coated. Mangroves need to keep their trunk and leave above the surface of the water.
Yet they also need to be firmly attached to the ground so they are not moved by
waves. Any part of root that appears above the water flows oxygen to the plant under
water surface. as the soil begin to build up, these roots procedure additional
roots that become embedded in the soil.
Volcanic
Eruptions
Volcanic eruptions have caused some of the worst disasters in the world. They
can wipe out entire cities and kill thousands of people. The name of volcano comes from Roman term. It derives from VULCAN which is the
name of Roman fire god. Romans believed that Vulcan lived on a volcanic Italian
coast. Romans called the island VULCANO. According to scientists, volcanic eruptions are divided in to four basic
groups. They are commonly known as Hawaiian, Strombolian, Vulcanian and
Peleean. The term of Hawaiian eruptions are named after the volcanoes in
Hawaii. These volcanic eruptions are the least violent type. They produce
highly fluid lava which flows quietly. This gradually builds up a shield
volcano. Strombolian eruptions are named after Stromboli. These result from the constant
release of gas from the magma. As the gas escapes, it produces tephra that
piles up, turning into a cinder cone. Strombolian eruptions happen when sticky
magma plugs the central vent. This makes the magmatic gas build up pressure
until it blasts. The magma is turned into volcanic dust and bombs. Vulcanian eruption which comes from the ancient Roman belief, are more violent
than the strombolian eruption. Vulcanian eruption happens and brings magma
which is more viscous. Vulcanian explosions are usually larger and noisier than
the Strombolian eruptions. Paleean eruptions are famous as the most violent kind of volcanic eruptions.
The name of paleean comes from the eruption of Mount Pelee, Martinique in 1902.
It killed almost 38 thousands people. A Peleean eruption occurs when the
magmatic gas build up tremendous pressure. This causes violent explosions with
glowing clouds of hot ash and dust.
RAIN FOREST
Rain forests cover about 10% of the earth, but
they contain 90% 0f the worlds animals and plants. Rain forests are found in
the hottest parts of the earth. Theyare situated in the area from the Tropic of
Cancer to the Tropic of Capricorn. This is the area on both sides of the
Equator.These forests are called rain forests because it usually rains there
everyday. The weather is always hot and humid. The main rain forests are in
America, Africa, and Asia. The largest area of rain forest is Amazonian in
South America. It isthree times larger than the whole of Indonesia.Indonesia
was covered by rain forests, but many of its forests have been cut down. Some fire also destroyed the Indonesian forests,
especially during the dry season. It is hard now to reforest the bare land.
Tsunami
The term of “tsunami” comes from the
Japanese which means harbour ("tsu") and wave ("nami"). A
tsunami is a series of waves generated when water in a lake or a sea is rapidly
displaced on a massive scale. A tsunami can be generated when the sea floor abruptly deforms and vertically
displaces the overlying water. Such large vertical movements of the earth's
crust can occur at plate boundaries. Subduction of earthquakes are particularly effective in generating tsunami, and
occur where denser oceanic plates slip under continental plates. As the displaced water mass moves under the influence of gravity to regain its
equilibrium, it radiates across the ocean like ripples on a pond. Tsunami always bring great damage. Most of the damage is caused by the huge
mass of water behind the initial wave front, as the height of the sea keeps
rising fast and floods powerfully into the coastal area.
WHAT IS TORNADO?
Tornadoes are known as one of the most damaging
disasters. What is the description of tornadoes? A tornado is a very powerful
column of winds which spirals around a center of low atmospheric pressure. A
tornado will look like a large blackfunnel which hangs down from a storm cloud.
The name "tornado" derives from the
Latin "tonare". It means "to thunder." Whilethe Spanish
developed the word into "tornear" which means "to turn or
twist". This is why a tornado is sometimes called twister or cyclone.The
winds inside a twister can spin around at speeds up to 500 miles an hour, but
it usually travels at roughly 300 miles an hour. This speed twisting makes a
tornado the most dangerous storm.The average tornado has a diameter of about
200 to 300 yards. The smaller tornadoes are known as satellite tornadoes. These
small offspring, about 50 yards across, can be very fierce and do lots of
damage.The forming of a tornado can be very quick. Sometimes it can form in a
minute orless. A tornado can travel across the ground at high speeds, then it
can suddenly vanish. Most tornadoes last less than twenty minutes and travel
less than 15miles. However, the super storms sometimes travel over 100 miles
before they areexhausted.
Hazardous Wastes
Hazardous wastes are solid, liquid, or gas wastes that maybe deadly or
harmful to people or environment and tend to be persistent or non degradable in
nature. Such wastes include toxic chemicals and flammable or radioactive
substance, including industrial wastes from chemicals plant or nuclear reactors,
agricultural wastes such as pesticides and fertilizers, medical wastes, and
household hazardous wastes such as toxic paints and solvents.
About 400 million metric tons of hazardous wastes are generated each
year. The United States alone produces about 250 million metric tons, 70
percent from the chemical industry. The use, storage, transportation, and
disposal of this substance pose serious environmental and health risks. Even
brief exposure to some of these materials can cause cancer, birth defects, nervous
system disorders, and death. Large-scale releases of hazardous materials may
cause thousands of deaths and contaminate air, water, and soil for many years.
Hazardous wastes of particular concern are the
radioactive wastes from the nuclear power and weapons industries. To date there
is no safe method for permanent disposal of old fuel elements from nuclear
reactors. Most are kept in storage facilities at the original reactor sites
where they were generated. With the end of the Cold War, nuclear warheads that
are decommissioned, or no longer in use, also pose storage and disposal
problems.