Natural Disasters: Natural Hazards, Earthquakes, Volcanoes

1522 Words7 Pages
Natural hazards are a natural phenomenon. There are three types; geological, hydro-meteorological and biological. Natural disasters have become increasingly frequent over time, making the global economic losses triple. Therefore risk management has become very important, especially for areas at high risk for natural disasters. Risk management involves identifying the risk of a hazard and the damage that would occur, and then trying to control the damage. This essay will discuss two natural hazards; earthquakes, volcanoes. It will then go into detail about the risk management processes for each hazard along with some case studies. Earthquakes are a natural disaster that occur frequently. However only some are at a magnitude that cause huge…show more content…
For example according to (www.usgs.gov), in 2014 the U.S Geological Survey National Seismic Hazard Maps shows earthquake ground motions for probability levels across America and are applied in seismic provisions of risk assessments, insurance rate structures, building codes and more. They developed these maps by studying information on potential earthquakes and associated ground shaking studies. Many lives are lost due to the collapse of buildings less than a few minutes after the main shocks. As said by Elsevier Science B.V (2002) there are two key elements in the urgent countermeasure. ‘One is strengthening of weak structures and other is short-term earthquake prediction’. Scientists can predict the probability of an earthquake occurring within a given time frame, but not when or where it will take place. Seismologists base long-term predictions on two pieces of information: identifying earthquake zones and calculating the average between successive earthquakes. They plot locations on active faults that have received little or no seismic activity for a long time. The plates in these regions are currently locked. These seismic gaps are likely locations to experience an earthquake. There are also early-warning systems using seismographs. These detect and signal immediate warning of primary waves – the first tremors of an earthquake. These 10-15 seconds is enough time for people to get under desks…show more content…
Most volcanic activity will take places at convergent and divergent plate boundaries, where plates are rifting and at hot spots. The most active volcanoes are on plate boundaries such as at the Pacific plate and its surrounding plates known as the ‘Ring of Fire’. Volcanoes occur when molten magma forces its way up towards the earth’s crust. The magma accumulates in a magma chamber. Gas and steam are held under very high pressure in the magma, and as the magma rises, the gases expand to hundreds of times to their original size. The magma eventually forces its way through a crack or hole in the ground surface and an eruption
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