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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.