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The earthquake caused very large ground motions with peak accelerations of 0.5 to 1.0 g in the Northridge area, decreasing to 0.1 g at distances of about 50 kilometers (31 miles). (A "g" of acceleration is equivalent to the acceleration of gravity. There were a few sites near the Northridge earthquake that recorded over 1 g of vertical acceleration. These ground movements would have been capable of throwing objects of any size into the air.)
The pattern of damage and strong ground shaking was irregular, with severe damage in places like Sherman Oaks and Santa Monica. These effects were caused by the complexity of the earthquake source and the wave propagation through complicated geology.
This is the largest earthquake to occur in the central Mississippi River valley since the 1811-1812 series in the area of New Madrid, Missouri. Structural damage and liquefaction phenomena were reported along a line from Bertrand, Missouri, in the west to Cairo, Illinois, in the east. Many sand blows were observed in an area southwest of Charleston, Missouri, and south of Bertrand, Missouri. Isolated occurrences of sand blows also were reported north and south of Charleston.
The most severe damage occurred in Charleston, Puxico, and Taylor, Missouri; Alton, and Cairo, Illinois; Princeton, Indiana; and Paducah, Kentucky. The earthquake caused extensive damage (including downed chimneys, cracked walls, shattered windows, and broken plaster) to school buildings, churches, private houses, and to almost all the buildings in the commercial section of Charleston.
(spacing added for clarity)
Reports from other cities:
Memphis, Tennessee, suffered no damage, except that two chimneys in the suburbs were shaken down.
In Pittsburgh, Pennsylvania, a slight earthquake shock was felt in the suburbs of Bellevue and McKeesport.
Every building in Indianapolis was shaken. Thousands of people were awakened.
The earthquake rattled windows in Kansas City, Missouri.
Electric lights flickered at the Union depot. Chimneys were damaged and plaster walls cracked in Grayville and Albion, Illinois; Princeton, Indiana; and Paducah, Kentucky.
(Emphasis Mine) (Source: Illinois State Geological Survey - 1995 )
1995 and beyond
Scientists calculate that moderately strong earthquakes, such as the Halloween 1895 quake, occur in the Central US every 70 to 90 years. There has not been one of this magnitude since 1895. Arch Johnston, director ,of the Center for Earthquake Research and Information in Memphis calculated the likelihood of a magnitude 6.3 quake or greater occurring within the next 50 years to be between 86 % and 94 %.
1980: An earthquake registering 5.2 on the magnitude scale originated in northeast Kentucky, where it was felt as an intensity VII. It was felt as an intensity II-III in southern Michigan.
1983: An earthquake registering 5.3 on the magnitude scale originated in the Blue Mountain Lake area of New York, where it was felt as an intensity VI. Detroit was on the outer edge of the area affected by the earthquare and experienced it as an intensity II-III.
1987: An earthquake registering 5.1 on the magnitude scale originated in Olney, Illinois.
This is the most damaging earthquake to occur in the Southeast United States and one of the largest historic shocks in Eastern North America. It damaged or destroyed many buildings in the old city of Charleston and killed 60 people. Hardly a structure there was undamaged, and only a few escaped serious damage. Property damage was estimated at $5-$6 million. Structural damage was reported several hundred kilometers from Charleston (including central Alabama, central Ohio, eastern Kentucky, southern Virginia, and western West Virginia), and long-period effects were observed at distances exceeding 1,000 kilometers.
Many acres of ground were overflowed with sand, and craterlets as much as 6.4 meters across were formed. In a few locations, water from the craterlets spouted to heights of about 4.5 to 6 meters. Fissures 1 meter wide extended parallel to canal and stream banks. A series of wide cracks opened parallel to the Ashley River, and several large trees were uprooted when the bank slid into the river.
Originally posted by Toots
Living in a central part of the U.S. that could potentially be affected by the New Madrid, I began to take an interest in the "what if" possibilities a few years ago. And especially after getting hit with a 5.3 last year! It was quite terrifying to experience. That one was a "roller," and quite unlike the 4.6 "shaker" that I experienced two years ago.
Doing some research, I came across an excellent technical report from the Mid-America Earthquake Center dealing realistically with a complete array of "what if" scenarios. It's a downloadable PDF document in 2 volumes. Volume II is especially interesting because it has an extensive list of bridges (complete with bridge history and pictures) that potentially would be affected by the New Madrid going off.
Here's the links:
Impact of New Madrid Seismic Zone Earthquakes on the Central USA, Vol I
Impact of New Madrid Seismic Zone Earthquakes on the Central USA, Vol II\
Hopefully some of you will find these reports as interesting as I did.
Be informed says:
Comment ID: 1360594
March 24, 2013 at 10:53 pm
The past few days the Mid Atlantic Ridge has been very active, this means likely to New Madrid will flare up within about 3 weeks to a month. You living in Tennessee live very close to this potential upheaval. I haven’t seen any strong indication of an imminent threat of something huge, but you can expect some movement from these areas being hit, especially all the earthquakes at between 54-60 degrees north on the Mid Atlantic Ridge. Start seeing movement between 14-20 degrees north and the New Madrid could let off a moderate quake. See a strong earthquake, mid to high 6 or larger at 14-20, and/or 54-60 degrees north, and that sucker could be getting ready to blow. You can see the latitudes on the USGS site.