No foolin' tremor jars Mid-South on April Fool's Day

Revised 8:30am - USGS indicates the magnitude has been reduced to 3.6 from an initial report of 4.0

April Fool's went out with a bang, or perhaps a rumble, yesterday as the New Madrid Fault Zone briefly reminded Mid-Southerners of its presence.  A magnitude 3.6 earthquake occurred in the far southern Missouri Bootheel at 10:52pm last night.

Yes Kristen it did! From social media reports and reaction to our posts on Facebook and Twitter, there were lots of folks that felt the tremor in the Memphis metro. Here's the quake page for this event from the USGS, which indicates that it occurred at 10:51:43pm on April 1 4km (2mi) S of Steele, Missouri (or about 80 miles north of Memphis) at a depth of 10.9km. There appear to be no initial reports of damage.

The New Madrid seismic zone of southeast Missouri and adjacent States is the most seismically active in North America east of the Rockies, according to the USGS and an unconfirmed report indicates that this was the strongest quake east of the Rockies since February 5, 2014.

Location of the April 1 earthquake relative to Memphis

The "Did You Feel It?" map from USGS indicates a lot of folks did!

Here's a seismograph from Gosnell, AR pic.twitter.com/GhfXcySoTh
— Ryan Vaughan (@ryanvaughan) April 2, 2015

Here's a seismograph from Memphis also. pic.twitter.com/JFeGJmbjLS
— Ryan Vaughan (@ryanvaughan) April 2, 2015

So, did YOU feel it? 

As an aside, HUGE thanks to MWN intern Kevin Terry who was all over this event as it occurred lat night and got the info out quickly on our social media accounts. Admittedly, I slept through it... another great example why #TeamMWN is the best around!

Erik Proseus
MWN Meteorologist

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Earthquake threat in the Mid-South

New Madrid Fault System, image courtesy UM-CERI

With all of the recent earthquake activity across the globe, I thought it would be a good time to review the earthquake threat that the Mid-South faces on a daily basis. Though not specifically weather-related, earthquakes fall into a broader "geography" or "earth sciences" category, of which meteorology is also a part. Therefore, it is appropriate to address here.

In the past 7 days, there have been 49 earthquakes of magnitude 5.0 or higher across the globe. A world map view shows that many are centered around the well-known and very active Pacific Rim. While this may be something akin to "normal," what has caught my attention are the number of magnitude 6.0 or higher earthquakes. On the 10th, a magnitude 6.5 occurred just off the northern California coast. And we all know about the 7.0 that struck Haiti on Jan. 12. That was followed by fourteen aftershocks of magnitude 5.0 or higher - all less than 24 hours after the initial quake - and dozens of smaller ones. One the 14th, a 6.0 rumbled southwest of Guam in the western Pacific. While this region is frequented by tremors, a 6.0 is still pretty strong even for the Pacific. On the 18th, another strong 6.3 quake occurred in the Drake Passage (between South America and Antarctica, south of Argentina). Finally, this morning, another 6.0 struck near the Guatemala/El Salvador coast. (All information above courtesy USGS.gov.)

We should be reminded that we live very near the New Madrid Fault System, which produced one of the strongest earthquakes in U.S. history 199 years ago (1811) and has the greatest earthquake risk east of the Rockies. A Fact Sheet published by the USGS details the continuing threat that this fault poses. In addition, an urban seismic hazard mapping report for Memphis was published by USGS in 2006 which may be of interest.

I would invite you to use this opportunity for education - know what you need to do to be prepared should an earthquake strike and what to do during and after a quake. The Fact Sheet quoted above indicates that the region could see landslides along the river bluffs, "ground failures [...] including soil liquefaction along the Mississippi River floodplain," impassable roadways due to bridge collapse or fissures in the road surface, disruption of agriculture and farmland flooding that could contaminate water sources, and failure of levees and riverbanks. With it's aging infrastructure, Memphis is "particularly vulnerable when subjected to severe ground shaking," including the possibility of building failure due to their being built prior to the writing of code that require seismic resistance.

None of this is meant to cause fear or worry, but instead to serve as a reminder that education and preparedness are key. Who knows when "the big one" may strike, but there is no indication that sometime in the future it won't.

For more information, visit these links:

United States Geological Survey Earthquakes Homepage

Earthquake Preparation - Before, During, and After an Earthquake (FEMA)

USGS Earthquake Notification Service

USGS Earthquake Info for Kids

University of Memphis Center for Earthquake Research and Information (CERI)

CERI's New Madrid Fault System page

Central U.S. Earthquake Consortium

ABC/Good Morning America Story (Jan. 18. 2010) on the central U.S. earthquake risk

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