[Homestead] Shake, rattle and roll

Lynda lurine at softcom.net
Sat Apr 19 01:52:06 EDT 2008


Well, that's one of the problems with California.  There is no "California." 
<g>  We probably should be several states since the areas are so different 
and the only connection is the freeways.

Up here in *real* Northern CA, particularly my little corner historically, 
we've lived with tsunamis for generations.  At least us *real* Californians 
have <g>  The local tribes tried to tell the folks who built Crescent City 
but they weren't interested in listening.  They do now and have all the 
alerts in place.

Humboldt Bay was formed by a tsunami in February 1690.  BIG quake and 
resulting tsunami.  Prior to that the "bay" was a multi-river delta.  The 
one fork of the Mad River disappeared, the Elk moved and the Bay was 
created.  Since the inlet to the Bay was never intended to be an inlet to 
begin with, it is mega hazardous.  One of the most dangerous in the world.

If you take a small plane up when the tide is out you can still see all the 
river and creek beds coming into the bay.

And, you're right.  Unless they get over 6, we just sleep right through them 
<g>

Lynda
----- Original Message ----- 
From: "EarthNSky" <erthnsky at bellsouth.net>
>
> 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
> Mercalli maps.
> 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
> people don't.
> 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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