<VV> H. Katrina

[Tony Underwood]

At 07:24 hours 08/31/2005, John Kepler wrote:
>with a breach in the levee the size of what's been on TV, they're
> > not gonna stop it.
>
>Never seen a good marine contractor at work, now have you!  They should have
>a significant amount of it "plugged" by tomorrow morning at the latest,
>assuming the Corps gets off it's dead ass and lets some pros do the work
>(sand/gravel filled barges make NICE, big levee plugs!)!
> >
> > The city has been sinking ever since it's been there.   The
> > continental crust in this region is weak (very large fault system
> > runs under the region)
>
>It does?

It's what my geology text books say...


>Please provide a cite!

...didn't get it from a site, got it from the geology books and a 
couple dozen geology documentary videotapes I've collected over the 
years of having fiddled around with this stuff (hobby 
pursuit).    There's a *great* geology department at VA Tech up the 
road, prompted me to get a library card so as to raid the library 
there, read up on silly stuff like strike faults and subduction zones 
etc ad nauseam.   It also detailed the fault system  running 
diagonally across my home state of VA, several of which also have 
rivers following them to the Atlantic seeing as how the faulted 
mantle is weaker, easily eroded, and since water takes the path of 
least resistance, VA rivers mostly (except for the New River which 
flows north into the Ohio River) all flow in a southeastern direction 
following the faults to the ocean... as do most of the rivers on the 
east coast which is shot through with northwest/southeast fault 
systems.    The midwest is stretched thin, thinnest continental crust 
in the American continent, and the Gulf region is on the southern 
edge of this stretched region and parked atop this deep buried 
ancient fault system which contains various spreading fractures in 
all directions as well as a number of salt domes which are 
isostostically rising and bending the crust around them as they rise, 
thus the weaker "floor" in the gulf region.

THIS is how I've been led to understand how the Mississippi delta 
region and the northern gulf is the way it is today.   It also 
explains how the region has so much oil...  but that's not the point 
at the moment (although as time passes, you can bet that gulf oil 
deposits are gonna become important).

There are a number of ancient fault systems underground leading up to 
the mid-continental region towards the New Madrid system, (not unlike 
the rift zone in Africa) which was active over 100 million years ago 
as it was evidently on its way towards splitting the N.A. continent 
and forming yet another inland sea  but then stopped, and only 
recently (appx several million years ago) has become active again 
which is what's causing the earthquake situation in the New Madrid 
area.    This fault system is old enough to have become buried miles 
below the surface by flooding of the Mississippi River which as 
previously mentioned follows the fault system straight down past New 
Madrid to the Gulf of Mexico seeing as how the area continues to 
subside as the weight of ground up Rocky Mountain sediments keeps 
getting deposited on the surrounding flood plain.   Being buried does 
not make it any less influential on the lay of the land.   Meanwhile, 
New Orleans continues to sink along with the surrounding countryside, 
which is how it came to be below sea level and how it's in a world of 
hurt as we speak.

If you want web sites....   I did do a quick search, found these...

http://www.oilfield.slb.com/content/services/software/geo/casestudy_geoviz_gulftest.asp 


http://www.agl.uh.edu/projects/vinton/Final%20Report/2.%203-D%20VSP%20imaging%20of%20Vinton%20Dome,%20LA/2.1%203-D%20multicomponent%20VSP%20imaging/2Northern%20Gulf%20of%20Mexico%20Continental%20margin%20Geology1.pdf 

(this one describes salt dome propagation along with the "lay of the 
land" in the northern gulf region including ancient fault systems 
with newer branches buried deep under silt and sand)

http://www.mines.edu/academic/geology/faculty/btrudgil/research.html
(more salt dome propagation and associated faults)

http://www.geol.lsu.edu/Faculty/Juan/GrowthFaults/abstracts.htm
(discussions of fault systems under Louisiana)

http://www.emporia.edu/earthsci/student/salley3/
(history of the Mississippi River basin and its fault line channel)

http://www.agu.org/meetings/sm05/sm05-sessions/sm05_G43A.html
(this one is pretty good, outlines the subsidence of the basin area 
of Louisiana)

>  and the city sits on a layer of river silts
> > and sand several miles thick which keeps loading the weakened crust
> > underneath, causing it all to slowly sink under the weight of the
> > river-deposit silt and sand above, thus N.O. keeps dropping lower and
> > the levees keep getting built higher and higher.
>
>Now just what geology text/monograph did you read that out of?


Uh...   the US Geological Survey...?


>Again,
>please cite!

See above links.


>Much of what you have expressed was out-of-date back when I was an undergrad
>geology student 35 years ago (part of the pre-plate tectonics "geosyncline
>theory")!

Check the dating of the papers listed in the above links.


>Yes, the area subsides.....it's a river delta which are
>geologically very special places and subsidance is part of the on-going
>lithification process, but not for the reasons you've stated (Google "salt
>domes" for an explanation!).

See the links.   They discuss salt domes but the domes are NOT the 
cause for the subsidence of the entire southern region of Louisiana.


>At least one reason it subsides is that human
>beings like to live on it and pump the water out from underneath it (water
>has volume folks....pump it out and the volume decreases, pump it in, it
>increases.....Google "Baldwin Hills Dam Disaster" for a referrence!)

The subsidence is also happening to the underwater terrain in the 
gulf.   Are people pumping water out from under this area as well...?

New Orleans is below sea level because for well over 100 years, the 
river has NOT been allowed to flood the area and deposit silts, sand, 
etc to maintain the level of the land.   The entire lower area of 
Louisiana is sinking at a rate of around an inch or more every 
year.   Each year, LA loses appx 20-30 square miles of landmass which 
is flooded by the gulf as the state slowly sinks.   Are people 
pumping that much water from wells to account for the sinking of the 
entire southern area of Louisiana?


> > Don't expect things in N.O. to ever get back to what would be
> > regarded as normal for a very long time.   It's gonna cost *all* of us.
>
>No arguement when it comes to The Big Easy......a shame too!  However, in
>the "Big Picture", the bulk of the petroleum infrastructure is located west
>of NO in areas that are both higher, more stable, and less effected by the
>hurricane.


Those were my understandings as well.   Made me wonder how all this 
could have such an effect on oil prices unless it was just another 
panic-button move by the oil companies being in fear of possibly 
losing a dime somewhere because they weren't quick enough to price 
gouge yet again.


>The off-shore rigs are built to higher standards than the Lake
>Ponchartrain levees, and if the preliminary reports are accurate, are
>largely undamaged.


...one of them was blown off its perches and washed up on the 
shore...  but the others are still there and serviceable etc 
according to news resources which tends to fly in the face of oil 
corporation claims that the fuel price increases are because of a 
"25% net drop in refinery product" because of the hurricane.


>The refineries around Convent/Gonzales are undamaged,
>and are only waiting for electric power and the pipelines to get cranked
>back up before they can be back in production.  At least as far as gas/oil
>is concerned, this looks to be more of a "speed-bump" rather than a "wall"


I'm wondering myself...

Makes me ponder what sort of effect will be had now that Bush has 
opened up the national petroleum reserves.

How will oil companies be able to justify these huge price increases then?


> > I'm kinda bummed out over this...  New Orleans is in a bad way and
> > it's getting worse by the minute and there's no end in
> > sight.    Anyway, I've rattled on long enough; the Red Cross is gonna
> > need some help...  anyone with a deep enough pocket might consider
> > lending a hand.
>
>Having a generational bias against the Red Cross, I'd suggest a donation to
>the Salvation Army.

That too.

The Red Cross is the first "rescue" organization that comes to mind 
at times like this... based on how it worked in the past in bad 
times; I suppose bureaucracy infects them like everything else...

>They do more in the field with less "parasitic"
>administrative costs (read that as fewer 6-figure Armani-suit types sucking
>at the money teat!).  If helping the people effected is your goal, the
>Salvation Army delivers more bang for the buck!


...you have a point, although any help from anywhere is better than 
none.   Here's hoping New Orleans gets a break; they sure need it.


tony..