Several small earthquakes have rattled the north-central Arkansas area this week puzzling many scientists as to their cause. The USGS has reported around 30 small earthquakes since this last Sunday and over 700 earthquakes in the last six months (over three per day). Most are ranging in magnitude around 1 to 3. Humans don't feel the quaking from the movement in the Earth's crust until around 2.5 to 3. Geologists have recorded earthquakes as high as a 4.0 in this region and predict some could occur as high as a 5 in magnitude.

Two basic theories have the attention of local authorities, the USGS and the gas exploration industry, yes the natural gas exploration industry! These two theories are centered around what is called a "swarm" of earthquakes and the other theory involves the use of water injection wells that literally fracture parts of the earth's rock interior to release natural gas. Some locals in Arkansas argue that the wells have had an increase in use and correlate with the increase in the number of earthquakes. A "swarm" is a short-term continuous series of small earthquakes in a region all ranging similar in magnitude. This is different from an usual larger earthquake with smaller aftershocks. The cause may be unknown.

Personally, the central states of the U.S. historically have been known to be struck with large earthquakes from the nearby New Madrid Fault as well but no one seems to be talking about this in reference to the swarm of earthquakes in Arkansas. Is it possible that swarms of earthquakes are not known to be caused by a large fault and therefore these in Arkansas are due to the natural gas exploration? Or, is this swarm related to the New Madrid Fault and political activists are using this opportunity to add a "strike" against the fossil fuel industry?

To argue your theory, consider the following:

1. Have swarms occurred in Arkansas before? If so, were these related to increases in well drilling?

2. How active is the New Madrid Fault? Are these swarms and this fault related?

3. Could there possibly be any other cause?

4. What evidence might link the cause to these small earthquakes?