[Homestead] Shake, rattle and roll
erthnsky at bellsouth.net
Fri Apr 18 18:53:23 EDT 2008
> That is the problem, no earthquake preparedness, either in buildings
> OR in response.
> Out here, all the native Californians know what to do, do panic and
> in most cities there are several volunteer groups ready to jump into
First, most people east of the Rockies don't know that they are at risk.
If they know about the NMFZ, they think that damage would be confined
to the river area between St. Louis and Memphis, when in fact, really,
only Florida escapes the hazard(and I read that today's quake was felt
in Niceville, FL, so go figure). While we have always known about the
crustal differences between the east coast and the west coast-at least
since the 1880's when the trio of quakes erupted, it has only been
relatively recently that we have a good understanding of why damaging
waves travel so far from the epicenter in areas east of the Mississippi
River. In recent years, we have also discovered and mapped new fault
zones. Today's quake was in the Wabash fault zone.
My point is that since California has been inhabited, it has been known
that large quakes are possible. Even before plate tectonics became
fashionable in the 60's, people knew to prepare and what to do in the
event of a quake.
On the contrary, most folks east of the Mississippi have lived here for
generations without knowing the dangers. Memphis, St. Louis, Chicago
and a few other cities now have codes in place, but it represents a
small part of the total infrastructure, and cities away from the area,
let's say Cincinnati and Atlanta, don't have such codes, at least I
don't think they do. NYC and Charleston SC have their own dangerous
earthquake zones, so they have codes for new construction, but again,
there's a lot of old infrastructure out there, and because it's been so
long since there was any activity, most people don't think about
preparing. There are no warning signs-small quakes- to remind them.
The Richter scale is pretty useless as a comparative tool for such
quakes, too. A 5.0 in California hardly draws a "whoa, did you feel
that?" whereas a 5.0 east of the Big River can shake more like a 6.5 or
a 7.0 due to the nature of the earth's crust. I have felt and heard
quakes with a magnitude of 2 that occurred 20 miles or so away here at
EarthNsky, yet I did not even wake up when sleeping on the floor
practically on the epicenter of a 5.0 in Washington state-(hey Linda and
Dennis!!!) I much prefer the modified Mercalli scale.
I know I have talked about all this before, so I will skip it now, but
if you go to the USGS site, the "did you feel it" maps are all modified
So much has been discovered since I was in school. The thought occurs
to me that the leaders of these various cities probably don't realize
that their city could be in danger even if it is 800 miles away. I am
kind of a geo freak and I keep up with this type of science, but most
California seems to be disaster central, and you would think that they
would be prepared for anything, but everyday, new discoveries are made
that change the hazard mitigation. For example, I wonder how many
people know that Catalina Island was created from an earthquake uplift,
and that such lifts and drops could generate a huge tsunami for the CA
coast? Do they teach this in schools now-after the Boxing Day tsunami,
this danger was finally revealed to Californians in general, but I
wonder if people knew this before. Do they know? Do they believe it
could happen again and are they preparing?
Bev, who has an earthquake rider on her homeowner's policy, just in case
the New Madrid starts roaring again.
BevanRon of EarthNSky Farm NW Georgia USDA Zone 7
34.498N 85.076W Bev is Earth, Ron is Sky
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