Friday, June 10, 2016

Earthquake Swarms in the Local 6 Area

It happens every few years or so...the uneasy "earthquake swarms" that erupt on the New Madrid Earthquake Zone right here in the Local 6 area. I think many of us like to put out of our minds that we live on one of the most active fault zones in the United States but the reality is that we record hundreds of very small tremors each year that we just can't feel.
Thanks to an increase in technology and social media, they are getting more attention each time they occur. Here is a quick glance at the past 30 days worth of earthquakes registered with the USGS for our region. (You can click the images to enlarge.)

These tremors range from 1.1 to 2.9 in magnitude, most of them either too small or too deep to feel on the surface of the earth. A cluster of earthquakes of this magnitude over a relatively shorter period of time is known as a "swarm". Most geologists agree that this is not necessarily a precursor to a larger quake and equally does not mean that the swarm will alleviate pressure along the fault to prevent a larger event. What it should do is serve as a reminder that we live on a very active fault line/zone and as we get futher in time since the last large quake event, the higher the risk becomes that one will occur. Are you prepared?

About six years ago I produced a 3-part series investigating more about the past, present, and future of the New Madrid Fault Zone on WPSD Local 6. You can watch it in it's entirety here:

Wikipedia also has a pretty good summary of past quakes and what scientists believe to be true about the fault zone. You can find that here.


  1. I have noticed that when there is a local quake it gets very little coverage.

  2. I have noticed that when there is a local quake it gets very little coverage.

  3. Interested in how you define a "swarm." There are, on average, approximately 300 earthquakes on the New Madrid fault system annually. Of the past 9 months, November 2015 had twice as many events (53) compared to May 2015 (25). For the time period Jan 1 through May 31, there were 117 events in 2015 compared to 94 in 2016. To me, the recent activity is no different than what's normally observed.