The following is a summary of my research paper written for Environment 102.
For the majority of society the word earthquake brings a variety of images to mind such as skyscrapers toppling over and buildings cracking or the earth splitting in two and swallowing Ms. Holloway’s Chihuahua whole either way these events seem to always happen on the west coast (where consequently California will break off at the state border and float out into the middle of the Pacific). What some people do not realize is that a fault line responsible for one of the most devastating earthquakes in United States history is located east of the Rocky Mountains in the Mississippi Valley.
Despite the common stereotype of an earth splitting natural disaster, earthquakes are generally the exact opposite. Earthquakes are the result of tectonic pressure beneath the earth’s crust. This pressure builds and the rocks bend and strain to accommodate the force but eventually it is too much and the rock slips and shifts releasing the pressure and causing an earthquake. This occurs around convergent boundaries, where two tectonic plates are colliding, and transform boundaries, where two tectonic plates are moving past one another. Earthquakes can also happen at divergent boundaries where plates are being pushed apart, but this generally only occurs in relation to sea floor spreading. All of these are inter plate earthquakes, ones that occur at plate boundaries, within areas that are known to have high seismic activity and expect as much. The New Madrid Fault is an ancient fault line that never materialized due to tectonic changes millions of years ago. This fault is very deep and the earthquakes are a result of the pressure this underdeveloped fault experiences at these depths. The New Madrid Fault causes intra plate earthquakes meaning they happen in the middle of a plate in areas that may not be properly prepared and educated in dealing with major earthquakes.
This is the case for most cities located near the New Madrid Fault. Although this fault is not widely known it has been around and has been producing notable seismic activity for centuries. This fault system stretches 120 miles beginning in Charleston, Missouri and ending in Marked Tree, Arkansas. It crosses the Mississippi River three times and the Ohio River twice and is responsible for over 200 seismic events each year The fault follows a pattern with a 4.0 or more quake every 18 months and a 5.0 or more quake once a decade. The New Madrid area does not experience as many tremors as the west coast but when there is any activity at all there is more damage. This is due to the different geological compositions of the two areas. Material amplification is increased shaking of sediment due to its composition and density. It means that waves from earthquakes, which actually cause the damage, move faster and are amplified when they move through unconsolidated material as opposed to tightly packed material.