February 21, 2011

Earthquake 4.0

For the last few months I have been following the seismic events along the New-Madrid Fault, specifically those in Arkansas. I have posted a few updates on the status of the fault-line here. This update- is a few days later than I had planned… and shows major increase in the number of earthquakes along the New-Madrid fault.

Apparently this activity has finally gotten the attention of the media; since I began writing this post there have been a few news-articles concerning the ‘quakes in Arkansas. Here are a few:

- http://www.4029tv.com/r/26932692/detail.html

- http://www.npr.org/templates/story/story.php?storyId=133828657 

I will begin with a quote-

"Since the development of the Richter scale to measure the severity of earthquakes, tremors from the New Madrid Fault have regularly appeared on its charts. The New Madrid zone averages about twenty minor events a month, registering at least a 1.0 on the Richter scale. About once a year, there occurs a tremor up to 3.0, and about once every ten years, there is a quake of 5.0 or greater."

-From: http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2219#

The norm, apparently, for the New Madrid Seismic Zone is to- obviously- have some seismic activity. However, the maximum "average" number of earthquakes per month is the same as the number of earthquakes which have happened in the past several days- per day. On Wednesday and Thursday, there were 20 earthquakes (each day) in Faulkner County, Arkansas- all within a 3-mile radius. Before 10:00 AM Friday morning there were 19 earthquakes in that same area, 2 of which were magnitude 4.0+. Over the rest of Friday and Saturday there were 19 more earthquakes, 2 of which were M3.0+. On Sunday and Monday, together, there have been 25 earthquakes as of 5:30PM, with 2 of those being M3.0+ earthquakes.

According to this website, http://www.historymania.com/american_history/Richter_scale, an M4.0 earthquake is considered a "light" quake, which normally causes "noticeable shaking of indoor items, and rattling noises. Significant damage is unlikely." But there have been a few of these earthquakes which were nearly an M5.0. The same website quoted above makes a statement concerning magnitude 5.0 earthquakes which says something to the effect of "major damage to unprepared buildings" being among the effects.

Anyway... Point being that there has been an escalated amount of seismic activity in this area of the earth as well as in other connected/significant areas, and that this is a symptom of much earth being moved under or at the surface. So, here are some pictures that I've gotten off of Google Earth over the last few days, with measurements and major cities included in the screenshot for perspective... -FYI, On all of the maps, the little orange dots represent earthquakes.

Below: A map of the USA showing the location of the recent earthquakes East of Texas, as of 2/19/2011.

Below: These are some maps showing the earthquake cluster in Arkansas, just above Conway and Greenbrier, as of Saturday.

 

 

 

 

 

 

 

 

Below: The same earthquake cluster on Monday, at 5:30PM.

arkansasCluster2-21-11

arkansasClusterCloseup2-21-11

 

 

 

 

 

 

 

 

 

Below: This map shows the two earthquakes in North Carolina this week. They are equally distant from Chattanooga, which is why I only made one measurement-line.

Below: This screenshot shows the earthquakes on the Missouri/Tennessee border this past week, as of 2/21/11.

 missouriQuakes2-21-11

Below: This map shows the distance from the earthquake on the tip of the Florida panhandle to New Orleans.

All of these earthquakes are along a connected group of fault-lines and are in the area where the continent would likely split due to weakness in the North American Plate- or the existence of another small plate in the Gulf. (See my main post on the subject: http://brightlight08.blogspot.com/2011/01/mid-america-earthquakes-and-their.html)

…And now I don’t really have anything else to say on the subject…So I guess I’ll be done with this update. Smile …Sianara!

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