1st student project - Term Paper Example

Download file to see previous pages... The geological reasons given to most earthquakes are the movment of tectonic plates, causing damage when two plates overlap, slide under or over or past one another. The puzzling aspect about the mid western quakes is that they do not come under the areas affect by fault lines or cracks. There is geological evidence that this area was shook by earthquakes during the period of A.D 490, A.D 900 and A.D 1450, after which there were quakes again in 1811 to 1812. The details imply a five hundred year pattern, under the theory that faults build up stress, causing these violent earthquakes as a let out. Another hypothesis that has been suggested as the reason behind the mid western quakes is the effect of ice glaciers from 20,000 years ago. Once the ice melted, lifting the load, the land began to rise but the mantle is not as flexible and takes longer to respond to the release of pressure. (findarticles.com). This is believed to have created unusual tension in the mid western continental United States, causing the New Madrid quakes. Scientists have pinpointed a number of faults that have caused earthquakes over the midwestern region, shown in the map below.
It is also believed by scientists after 9 years of observation, that the New Madrid fault line might be shutting down, as it has shown no activity in the observation span. As a consequence, the risk calculations have varied wildly, from a 10 percent chance of a disastrous earthquake in the next 50 years to a chance of just 1 percent or less. (Choi, 2009).
The Lower Wabash Valley of southwestern Indiana and adjacent parts of Illinois is seismically active. (Hill, 2002). There have been reports of earthquakes in parts of southwestern Indiana, affecting different parts in the years 1968, 1987 and 2001. It has been noted that the Lower Wabash Valley is capable of causing disastrous earthquakes at any time. ...Download file to see next pagesRead More