Everything about The New Madrid Earthquake totally explained
The
New Madrid Earthquake, one of the largest
earthquakes ever recorded in the
contiguous United States, occurred on
February 7,
1812. It got its name from its primary location in the
New Madrid Seismic Zone, near
New Madrid,
Louisiana Territory (now
Missouri).
This earthquake was preceded by three other major quakes: two on
December 16,
1811, and one on
January 23,
1812. These earthquakes destroyed approximately half the town of New Madrid. There were also numerous aftershocks in the area for the rest of that winter.
There are estimates that the earthquakes were felt strongly over, and moderately across nearly one million square miles. The historic
San Francisco earthquake of 1906, by comparison, was felt moderately over .
Effects
Based on the effects of these earthquakes, it can be estimated that they'd a magnitude of 8.0 on the
Richter scale. As a result of the quakes, large areas sank into the earth, new lakes were formed (notably
Reelfoot Lake,
Tennessee), and the
Mississippi River changed its course, creating numerous geographic
exclaves, including
Kentucky Bend, along the state boundaries defined by the river.
Some sections of the Mississippi River appeared to run backward for a short time.
Sandblows were common throughout the area, and their effects can still be seen from the air in cultivated fields. Church bells were reported to ring in
Boston, Massachusetts and sidewalks were reported to have been cracked and broken in
Washington, D.C.
Disaster relief
A request, dated
January 13,
1814, by
William Clark, the governor of
Missouri Territory (the territory was renamed soon after the quake to eliminate confusion with the new state of
Louisiana), asked for federal relief for the "inhabitants of New Madrid County". This was possibly the first example of a request for disaster relief from the US Federal government, which would later become the job of the
Federal Emergency Management Agency.
Epicenter
The
Reelfoot Rift goes back about 750 million years, to when the entire landmass of the earth constituted a single
supercontinent, designated now as
Rodinia. At the time a constructive
fault zone began to form, now called the Reelfoot Rift, but it failed, and the zone became inactive.
About 550 million years later, at the time of the supercontinent called
Pangaea, the fault zone again became active but no longer functioned as a constructive plate and remains in the same condition today. The earthquakes are therefore traced to seismic activity 5 to 25 kilometers (3-15 mi) below the
crust of the earth.
Seismic Zone - 20th century
The epicenters of over 4,000 earthquakes can be identified from seismic measurements taken since 1974. It can be seen that the earthquakes originate from the seismic activity of the Reelfoot Rift. The zone which is strongly colored in red on the map is called the
New Madrid Seismic Zone.
Topographic changes
Almost 200 years after the earthquakes in 1811 and 1812, the course of the Mississippi River as it was before the events is still visible in the landscape of the affected areas today. Along and parallel to the
Tennessee/
Arkansas state line, the shrunken riverbed is still present.
The
old riverbed, however, still defines state lines along the river, resulting in numerous small jogs where the borders divert away from the river and incorporate small
exclaves of land on the opposite side of the river from the rest of their state.
Such exclaves include the
Kentucky Bend, a part of
Kentucky whose only land boundary is with
Tennessee, and the town of
Reverie, Tennessee, which lies on the
Arkansas side of the river.
Recent earthquakes
The zone remains active today. In recent decades minor earthquakes have continued.
On April 18th, 2008
a 5.2 earthquake struck near the southern borders of Illinois and Indiana.
The epicenter was 19 miles SE of Olney, Illinois - close to the Ohio/Wabash rivers. A second earthquake followed less than 6 hours later just north of the region of the previous quake and registered a 4.6.
»
Understanding of this earthquake zone is growing slowly in comparison to awareness of the
San Andreas fault.
Earthquake preparedness
The situation is more precarious than it was in 1811. The area is more densely populated, and many buildings have no
earthquake resistant construction.
A few states have joined forces and founded a special institute for their earthquake zone, to prepare as well as possible for a major earthquake. The Mississippi River will probably present one of the incalculable problems. A few emergency funds for earthquake victims have been founded. Measures are also being ordered to mitigate any
natural disaster resulting from an earthquake; thus in the construction of dams, bridges, and highways, earthquake safety is particularly being taken into account.
Gallery
Image:NMSZ_Erdbeben.jpg|Reelfoot Rift and NMSZ
Image:Reverie_ms_river_s.jpg|View to the southwest along the former riverbed of the Mississippi River, south of the Tennessee/Arkansas state line near Reverie, Tennessee and Wilson, Arkansas (2007)
Image:Reverie_ms_river_n.jpg|View to the northeast
Image:NMSZ_Vergleich.jpg|Damage-range comparison between a moderate New Madrid zone earthquake (1895, magnitude 6.8), and a similar Los Angeles event (1994, magnitude 6.7).
Further Information
Get more info on 'New Madrid Earthquake'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://new_madrid_earthquake.totallyexplained.com">New Madrid earthquake Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
