Natural disasters are not always the result of natural causes. Some disasters are man-made. For example, earthquakes and floods are both the result of man’s activity. In some cases, man has created disasters by his own actions.
Earthquakes and Floods
There are many reasons why a natural disaster can occur. Earthquakes and floods are two of the most common natural disasters. Earthquakes are caused by tectonic plate movement. This occurs when plates collide or move over each other. Tectonic plates are made up of rock and sediment that are being pushed together. When they collide, the pressure increases and eventually breaks the rock apart. The resulting cracks in the earth’s surface cause earthquakes.
Flooding occurs when the water table rises above its normal level. Water is then released from underground reservoirs and comes rushing to the surface. It can also be caused by rainstorms, snow melt, or ice melt. Floods are often the result of heavy rainfall. Heavy rains can also cause flash floods. Flash floods happen when a large amount of water rushes down a river or creek. Flash floods can occur at any time, but are more likely to happen during spring and summer months.
Tornadoes
Tornadoes are another type of natural disaster. They are caused by strong winds. Tornadoes are called twisters in the United States and tornadoes in Canada. Tornadoes can also be called cyclones in Australia and cyclones in New Zealand. The term tornado is used to describe the spinning motion of the winds in the center of the storm.
Hurricanes
Hurricanes are storms that are formed over warm ocean waters. Hurricanes can form anywhere in the world. Hurricanes can also form over land, especially in tropical areas. Hurricanes are usually very strong. Hurricanes can reach speeds of up to 150 miles per hour. Hurricane winds can also reach 100 mph or higher. Hurricanes have the ability to generate high amounts of precipitation. This precipitation can lead to flooding.
Tsunamis
Tsunamis are waves caused by underwater earthquakes. Tsunamis are also known as tidal waves. Tsunamis can travel for hundreds of miles. The tsunami was first discovered in Japan in the year 869 A.D.
Volcanoes
Volcanoes are formed when lava erupts from the earth’s surface. Volcanic eruptions can be small or large. Small eruptions produce small amounts of lava. Large eruptions produce large amounts of lava. Large volcanic eruptions can also produce ash clouds. These ash clouds are often dark gray in color. The ash clouds often block out the sun and cause global cooling. The ash clouds also contain sulfur dioxide. Sulfur dioxide is a gas that can damage human lungs.
The earth’s crust is made up of many layers. The top layer is called the crust. The crust is made up of rocks and sediments. Below the crust is the mantle. The mantle is made up of molten rock. The mantle is also known as magma. The mantle is the hot spot that volcanoes are built on. Beneath the mantle is the core. The core is made up of molten iron. The core is the hottest part of the planet. The core is also the most stable part of the planet. Beneath the core is the outer core. The outer core is made up of liquid iron. Beneath the outer core is the inner core. The inner core is made up of solid iron. Beneath the inner core is the mantle. The mantle and the core are made up of molten rock. Beneath the mantle is a layer of liquid rock. This layer is called the asthenosphere. Beneath the asthenosphere is the lithosphere. The lithosphere is made up of solid rock. Beneath the lithosphere is the upper mantle. The upper mantle is made up of molten rocks. Beneath the upper mantle is the lower mantle. The lower mantle is made up of solid rock.
