Increased Awareness - Earthquake Hazard in Missouri

Disaster movies are often the film industry's way to attract viewers and provide for exciting entertainment. Often, at the expense of reality, these type films peak the audience's interest, but fuel their fears as well. Recent attention has been directed at earthquakes associated with the San Andreas fault in California. It is only natural that people in Missouri concerned about earthquake hazards in the Midwest would feel the need to ask questions about the New Madrid Seismic Zone located in part within southeast Missouri.

"Most Missourians do not realize that there is an earthquake in our state almost every day. The size of these earthquakes are in the range of 1-2 magnitude which means that they rarely are felt by humans; but they can be recorded on devices that measure the earth's movement," said Mimi Garstang, Missouri's State Geologist. These earthquakes are evidence that a seismically active fault system is present in the southeastern portion of our state. This system is called the New Madrid Seismic Zone and it extends through a multi-state area. The movement along this fault system occurs thousands of feet below ground surface. However, because of both the extent and depth of this fault, it has the potential to cause damage and impacts across a large area of the central United States.

Geologic studies indicate that large earthquakes occurred along the New Madrid Seismic Zone in approximately 300 AD, 900 AD, and 1400 AD. Most Missourians have heard of the more recent 1811-1812 flurry of quakes that were in the range of magnitude 7-8 and centered near New Madrid, Missouri. Because few people lived in Missouri in the early 1800s, impact to human life was minimal. The three major earthquakes in late 1811 and early 1812, however, did permanently change the course of the Mississippi River and created the Reelfoot Lake in the northwest corner of Tennessee.

Missourians should be aware of the reality of earthquake hazards in our state. However, we must also understand that an earthquake measuring as large as 10.5 as depicted in a recent disaster film, is probably only fiction. Some scientists predict that there is about a 10 percent chance of a magnitude 7-8 earthquake along the New Madrid Seismic Zone in a 50 year time interval; which is a more realistic estimation of the size of a large earthquake that may occur in our state. The most valuable lesson we can learn from viewing a natural disaster movie is that knowledge and preparation are key. We should channel the energy associated with an increased awareness level into positive activities that will help prepare for actual earthquake risk associated with the New Madrid Seismic Zone. The Division of Geology and Land Survey has worked cooperatively with the U.S. Geological Survey for several decades to increase the knowledge base on earthquakes in the central United States. For additional information, booklets or answers to questions, please contact the Division of Geology and Land Survey 573-368-2143.  We are located in Rolla, Missouri at 111 Fairgrounds Road.