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*Natural Disasters and How They Are Formed*
Earthquakes are the shaking, rolling or sudden shock of the earth’s surface. They are the Earth's natural means of pretty much releasing stress. More than a million earthquakes shake the world each year. The West Coast is most at risk of having an earthquake, but earthquakes can happen in the Midwest and along the East Coast. Earthquakes can be felt over large areas although they usually last less than one minute. Earthquakes cannot be predicted as to really when they will strike , although scientists are doing a great amount of work on it!
The size or aka. the magnitude of earthquakes are determined by measuring the amplitude of the seismic waves recorded on a machine called the seismograph and the distance of the seismograph from the earthquake. These are put into a formula which converts them to a magnitude, which is a measure of the energy released by the earthquake. Ok so we do know that the earth has four different major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet. But this skin is not all in one piece, it is made up of many pieces like a puzzle covering the surface of the earth. So not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle pieces 'tectonic plates', and the edges of the plates are called the 'plate boundaries'. The plate boundaries are made up of many faults, and most of the earthquakes around the world pretty much occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there you have it, an earthquake.
During an earthquake there are two main types of body waves. The primary wave (or P-wave) and the secondary wave (or S-wave). When an earthquake hits, the first thing you feel is the primary wave. The primary wave moves faster and therefore arrives at a particular location first, however when you think it's safe to come out from under your table or where ever it is you are hiding, the secondary wave (S-wave) hits! Unlike the primary wave, this one is transverse, which means that the vibration is at a 90 degree to the direction the wave is moving. You can think of this as a ripple in the ground. This motion is much more dangerous to buildings and of course to humans, because it moves the ground in a variety of directions at once and can cause it to split apart.
Electricity, water, gas and telephones may not be working after an earthquake since it will knock down half of the power grids in your town. The police and fire departments are likely to be tied up. You should be prepared to fend for yourself for at least three days, preferably for a week.
You'll need food and water (2 gallons a day per person), a first aid kit, a fire extinguisher suitable for all types of fires, flashlights; a portable radio, extra batteries, blankets, warm clothes, shoes and money (ATMs may not work so you'll need cash in handy), medication; an adjustable or pipe wrench to turn off gas or water, if necessary; baby and pet food; and an alternate cooking source (barbecue or camp stove). This list can also be applied to other disasters, such as floods or wildfires.
A volcano looks like a mountain, although they are two different things. A mountain is a large natural rise of the earth's surface, more like a giant heap of sand. A volcano is also like a big heap of earth, that has a vent where all the mixture of lava, ash, dust, and other substances that have piled up over many years. It pours out of an opening in the earth after an eruption.
Most volcanoes are formed by the movement of tectonic plates on the surface of the earth. These plates are basically huge pieces of rock that ‘float’ on the mantle. The tectonic plates are in constant motion, albeit very slow motion. When a tectonic plate sinks, it sinks down into the mantle and becomes very hot. So hot, in fact, that the rock melts. This molten rock will gradually make its way up to the surface of the earth through a series of cracks. A volcano begins as melted rock (aka. the magma) which rises from deep inside the earth toward the surface. As the gas filled magma rises, it melts gaps in the surrounding rock and forms a large chamber. Pressure from the solid rock around it forces the magma up to the surface through the conduit (channel) in a weakened part of the rock.
You've heard of the Ring Of Fire, but do you know what it means? Well the Ring of Fire is a long chain of volcanoes and other tectonically active structures that pretty much surround the Pacific Ocean. The chain runs up along the western coast of South and North America, crosses over the Aleutian Islands in Alaska, runs down the eastern coast of Asia past New Zealand and into the northern coast of Antarctica. The Ring of Fire is one of the most geologically active areas on Earth, and is a site for frequent earthquakes and powerful volcanic eruptions. There are other Volcanoes around the world, which one of the most famous being Mt. Vesuvius located in Italy. Vesuvius is the only active volcano in mainland Europe, and has produced some of the continent's largest volcanic eruptions.
A Day in Pompeii - Full-length animation
Hurricanes and Tornadoes
Hurricanes and Tornadoes
Hurricanes are large, swirling storms with winds that go from 119 kilometers per hour (74 mph) or higher and that's faster than a cheetah, the fastest animal on land. Some hurricane winds can go up to 252 km/hr. The storms form over warm ocean waters and sometimes strike land. When a hurricane reaches land, it pushes a wall of ocean water ashore and bringing a massive flood along with it too. This wall of water is called a storm surge, which along with heavy rain can cause flooding, especially near the coast.
Hurricanes form over the warm ocean water of the tropics. When warm moist air over the water rises, it is replaced by cooler air, and we all know that hot air rises. The cooler air will then warm and start to rise. This cycle causes huge storm clouds to form. These storm clouds will begin to rotate with the spin of the Earth forming an organized system. If there is enough warm water, the cycle will continue and the storm clouds and wind speeds will grow causing a hurricane to form. Another huge part of Hurricanes are thunderstorms which are the driving factors for a formation of a Hurricane.
There are some differences between a Hurricane and a Tornado. A tornado appears as a giant rotating, funnel shaped cloud that extends from a thunderstorm to the ground with whirling winds that can reach up to 300 mph. Damage paths can be in excess of one mile wide and 50 miles long. Some tornadoes are clearly visible, while rain or nearby low-hanging clouds can block others from being seen. Occasionally, tornadoes develop so rapidly that little, or if any, advance warning is possible. Tornadoes cause an average of 70 fatalities and 1,500 injuries in the U.S. each year. The average tornado moves Southwest to Northeast, but tornadoes have been known to move in any direction. “Tornado Alley” is a nickname given to an area in the southern plains of the central U.S.
Some of the widely known hurricanes are: Hurricane Wilma, 2005, Hurricane Sandy 2012, Hurricane Andrew 1992, Hurricane Katrina 2005
Forests have developed around fire occurring both naturally and intentionally. Lightning is the most common source of naturally caused fires. Native Americans first used forest fires to encourage and increase game forage potential, to reduce the understory for easy travel and to herd potential prey toward hunters. Naturally caused forest fires are usually started by dry lightning where little to no rain accompanies a stormy weather disturbance. A general maximum speed of between 16 and 20 km/hr (9 to 12.5 mph) for wildfires. A fire’s forward rate of spread naturally depends on many factors, particularly wind and other weather conditions; fuel type and condition; and terrain.
Forest fires are common in places around the world where climates are moist enough to allow the growth of trees and shrubs, but have extended dry, hot periods. The most noted areas on Earth for wildfire include the vegetated areas of Australia, Western Cape of South Africa and throughout the dry forests and grasslands of North America and Europe.
A Tsunami is a series of large waves of extremely long wavelength and period usually generated by a violent, impulsive undersea disturbance or activity near the coast or in the ocean. Often the term, "seismic or tidal wave" is used to describe the same phenomenon, however the terms are misleading, because tsunami waves can be generated by other, non seismic disturbances such as volcanic eruptions or underwater landslides, and have physical characteristics different of tidal waves.
Most tsunamis, about 80%, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common. Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean. Tsunamis race across the sea at up to 500 miles (805 kilometers) an hour about as fast as a jet airplane.
Some safety tips:
When in coastal areas, stay alert for tsunami warnings.
Plan an evacuation route that leads to higher ground.
Know the warning signs of a tsunami: rapidly rising or falling coastal waters and rumblings of an offshore earthquake.
Never stay near shore to watch a tsunami come in.
Do not return to an affected coastal area until authorities say it is safe.
First Aid Only All-purpose First Aid Kit, Soft Case, 299-Piece Kit
Natural Disasters and How They Are Formed
© 2016 Mahsa S