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Earthquakes - the diverse variety of physical (geological and geographic) and human (economic, political and historical) factors that influence how significant an earthquake can be

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Earthquake Show how the impact of earthquakes varies with the scale of the hazard & other factors. There are a diverse variety of both physical (geological and geographic) and human (economic, political and historical) factors that influence how significant an earthquake can be. The magnitude of the earthquake can be measured by seismographs using a logarithmic Richter scale, measuring the earthquake strength. However this often bears little resemblance to the actual impact of the earthquake, (which can be measured using the descriptive / qualitative Modified Mercalli scale which measures the physical effect of the earthquake) for the following reasons... One of the ideas that must be considered is how the magnitude of the earthquake is not directly proportional to the intensity of the earthquake as there is a considerable distance between the focus (point of fracture) and epicentre (point on surface vertically above focus on earth surface). If the focal point is 'shallow' (under 70km deep) then the impact of the earthquake is greatest, but if the point is e.g. 500km deep then potential impact is reduced. However it is usually accepted as a generalisation that a more powerful earthquake can potentially cause greater damage. ...read more.


Although it is still a technological impossibility to accurately predict earthquakes, there have been some scientific advances in nations such as Japan, China & USA. However, the plate tectonics theory can be used at a global scale, and regionally previous data could be used to predict forthcoming quakes. However it is not possible to predict the exact date or intensity of these - Predicting an earthquake hours before its occurrence is based on e.g. changes in groundwater levels, radon gas emission (by measuring the rate of decomposition in boar holes) and animal behaviour. Particularly in the United States, complex GIS systems are being used to create hazard maps, taking the likes of liquefaction and landslide potential into consideration (Californian "Earthworm" mentioned below). Community preparedness is a key factor in managing the hazard, and there are two levels - Public preparedness as well as Government / emergency services preparedness. Authorities make sure the most appropriate action is taken by analysing previous experiences. A general initial public response that is requested in the event of an earthquake is to have emergency supplies in stock, move under protective furniture and then await rescue - a strategy obviously aimed at minimising potential risk. ...read more.


Although the Californian GIS system appears to be very impressive and enable a near instant response to earthquakes, these are simply future plans and technology is still being developed; little of the aims have yet been implemented. In 1990, the Japanese government allowed transference of some of Tokyo's power to other, less earthquake-prone regions such as North Honshu. Whilst this is a good idea as it reduced potential economic / administrative difficulty be there an earthquake in Tokyo, realistically a quake in Tokyo would affect the global economy. Although one would think that a government would try and help the citizens as much as possible following a disaster, aid movements in the past have been hindered. After the 1995 Kobe quake, Japan initially adamantly refused to accept foreign aid (although it had a shortage of e.g. medical teams). After the Izmit disaster in Turkey 1999 the government slowed down Aid transfers by imposing import duty on them, and also refusing to accept Greek blood although many were in desperate need for blood. In Mexico 1985, the government hindered aid movement for the first few days by believing they could cope with the crisis without any external help. In such examples governments have prioritised pride over the welfare of their citizens. Muppets. ...read more.

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