New Madrid fault, its effect on cities, and on Kansas City?

[advocrat]

Brick fares better than most other building materials my friend.

Back in college, a geography prof I had described his on-the-street eye-witness experience of the Bakersfield quake that happened 40-50 years ago. He described the effect on brick buildings with hand gestures to describe, "the bricks popped off the the buildings upper walls, and into the air and down like onto the street like dominoes."

Several years back I read a damage scenario for New Madrid quake, if it goes off at around an 8 magnitude. Memphis would be devastated, St. Louis has heavy damage, and Kansas City would even have a little, something more than pictures off of the wall, but less than structural collapse. This report implied that certain structures in KC might have cracks in walls, etc., as a result of being built on small pockets of unstable strata, or just poor construction.

[Highlander]

Several years back I read a damage scenario for New Madrid quake, if it goes off at around an 8 magnitude. Memphis would be devastated, St. Louis has heavy damage, and Kansas City would even have a little, something more than pictures off of the wall, but less than structural collapse. This report implied that certain structures in KC might have cracks in walls, etc., as a result of being built on small pockets of unstable strata, or just poor construction.

The USGS predicts moderate damage for St. Louis with a 7.7 fault centered on the New Madrid Fault zone.  Follow the link on my last post and it has a map of projected damage zones and a description of the type of damage expected. 

[LenexatoKCMO]

Brick fares better than most other building materials my friend.

Are you making this up as you go?  Complete opposite of the truth.

[anniewarbucks]

A quake of any magnitude only does damage to those structures that are not earthquake retrofitted. ST Louis has been retrofitting their structures for some time now to withstand earthquakes. True the arch is not retrofitted or most of the historic buildings in St. Louis but most new buildings and roadways are being built with the new standards.

[49r]

That is a little hard to understand...

[tjokskalle]

  What most people dont know is that St Louis sits on an huge cave system that was first
used by indians and then by white settlers as living space.A huge quake could be devastating
to the metro area as the caves could callapse.If the new madrid fault slips big,the shock waves will
travel faster than a quake on the west coast and do more damage because the midwest area sits atop
a substrata layer of sand and tremors move easier through sand.At the time of the great quake in new madrid,sand shot up from fissures and covered crops and the like;in some areas crude oil spout up and
covered large areas.When i bought my brick home,i made sure i had qauke insurance!

[ShowMeKC]

And a lot of the brick buildings cannot be reinforced easily, the best they can do (from what I understand) is save the building itself, whereas the brick portions, especially the facades, will be screwed.

While we know most new buildings and highways are being fitted for earthquakes, that still leaves a TON of buildings in St. Louis open to damage from earthquakes.

[Highlander]

  What most people dont know is that St Louis sits on an huge cave system that was first
used by indians and then by white settlers as living space.A huge quake could be devastating
to the metro area as the caves could callapse.If the new madrid fault slips big,the shock waves will
travel faster than a quake on the west coast and do more damage because the midwest area sits atop
a substrata layer of sand and tremors move easier through sand.At the time of the great quake in new madrid,sand shot up from fissures and covered crops and the like;in some areas crude oil spout up and
covered large areas.When i bought my brick home,i made sure i had qauke insurance!

I think the earthquake threat to St. Louis is overblown, at least in terms of the city suffering major damage.  Any cave system under St. Louis had to survive the New Madrid quakes in the 1800's and I have my doubts as to how vulnerable it would be given another large quake (or even how extensive it is).  Earthquake waves in the midwest may travel a bit farther than their California counterparts because the strata here is not as compartmentalized by faulting but it's unrelated with a substrata of sand.....waves don't travel far or fast in unconsolidated material, they may increase in amplitude for a short distance but attenuation will occur much more quickly.  St. Louis would receive moderate damage from a large quake in the New Madrid area but the probability of a large quake being epicentered closer to the city drops off dramatically because the reelfoot rift seismic activity is extremely concentrated.  There are earthquakes that are epicentered closer to St Louis than New Madrid that are not associated with the rift but the geology is entirely different than in the New Madrid area and there is nothing to suggest that this area could produce the large quakes seen further south.   

[warwickland]

A quake of any magnitude only does damage to those structures that are not earthquake retrofitted. ST Louis has been retrofitting their structures for some time now to withstand earthquakes. True the arch is not retrofitted or most of the historic buildings in St. Louis but most new buildings and roadways are being built with the new standards.

about the only recent retrofits (or earthquake proofing) i know of recently in the entire metro are elevated sections of highway farty in downtown.

[DefaultAlias]

Even a moderate earthquake would cause considerable damage to St. Louis. All of those brick and mortar structures prone to collapse. I suppose we could send them all to KC.

[DefaultAlias]

Does anyone know if the City of St. Louis has started retrofitting its structures or not? I certainly hope so given all the great architecture in the city.

[ShowMeKC]

I think the skyscrapers and the new buildings, highways and some bridges would be ok, but from what I understand, the older buildings, masonry buildings, the Arch, and older highways/bridges would be done for. Also from what I've read/heard, if the masonry buildings were more reinforced, the buildings would survive, but their masonry facades wouldn't survive.