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inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #101 of 126: Andrew Alden (alden) Sat 7 May 11 13:30
    
The Catholics have several saints designated for earthquakes, foremost among
them Saint Emidius. After the 1857 earthquake in southern California, the
local bishop got permission to observe the saint's feast day. Around that
time, too, the mountains near the epicenter got their current names, the San
Emigdio Mountains and the Temblor Range.

But that's neither here nor there...

There are ways to open and close a crack in the ground big enough to swallow
a man. You could have a landslide or just a riverbank slump that would open
a headscarp crevasse, then the uphill side could slump down upon it. In the
tumult of a major quake, most people wouldn't be able to tell the real
cause.

Apparently after 1906, when a team of geologists was exploring the San
Andreas fault, one of them was fooled by a farmer who stuck one of his dead
cows into the fault trace, hind end up. We can never rule out the
capriciousness of humans.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #102 of 126: Mark McDonough (mcdee) Sat 7 May 11 13:36
    
Hah, that's great!  
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #103 of 126: Sharon Lynne Fisher (slf) Sat 7 May 11 16:18
    
Back in the 1980s, I think it was, the San Francisco librarian got
curious about how the official death toll of the earthquake seemed so
small when it seemed to her that she'd run across a lot more people
than that who were claimed to have died in the quake. So she started
keeping track and discovered that was indeed true. She also discovered
things like photos where buildings destroyed by the quake were drawn
back in again, and then had big clouds of smoke painted over them --
because insurance paid for fire and not for earthquakes. The book
published about it was Denial of Disaster.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #104 of 126: Mark McDonough (mcdee) Sat 7 May 11 17:22
    
Right, that was my memory of the controversy too.  Yes, some of the
really big modern buildings did survive (in some cases only to be
burned) but there was a lot more death and destruction from the quake
than was admitted at the time.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #105 of 126: Sharon Lynne Fisher (slf) Sat 7 May 11 17:51
    
>only to be burned

Dynamited, in some cases.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #106 of 126: Mark McDonough (mcdee) Sat 7 May 11 18:06
    
Right!

I just thought of another area that had a huge earthquake in historic
times that most people don't think of as a high hazard area: Jamaica. 
In 1692, as all pirate fans know, the pirate haven of Port Royal was
almost completely destroyed by an earthquake.

Is the Caribbean basin an earthquake hazard area, and if so, would
this expose the east coast of the US to tsunami hazards?
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #107 of 126: Sharon Lynne Fisher (slf) Sat 7 May 11 18:19
    
I'd forgotten about that one.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #108 of 126: Andrew Alden (alden) Sat 7 May 11 19:23
    
The US Geological Survey is constantly doing studies about the tsunami
hazard of Puerto Rico. But the threat is much greater to the island itself
than to the continental USA.

An unknown tsunami threat to the east coast is landslide tsunamis. All of
the North Atlantic is susceptible. A large slide offshore of Norway
inundated Scotland about 8,000 years ago; you can google it as the Storegga
slide.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #109 of 126: Sharon Lynne Fisher (slf) Sun 8 May 11 07:47
    
Wow. I didn't know Great Britain used to be attached to Denmark.

And, oh goody, one of the causes of the Storegga Slides is thought to
be methane release.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #110 of 126: Peter Meuleners (pjm) Mon 9 May 11 10:49
    
There is a good NatGeo show on that land area.  It's one of the many
sources for the Atlantis myth.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #111 of 126: Mark McDonough (mcdee) Mon 9 May 11 16:57
    
It may be one of the reasons people were kinda slow to build large
coastal cities in Europe.  Oral tradition might well have preserved
that tale.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #112 of 126: Michael C. Berch (mcb) Mon 9 May 11 17:31
    
Hmmm, interesting hypothesis. I can think of a lot of counter-examples
from early ages, though -- Athens, Constantinople, Jaffa, Venice,
Marseilles, Barcelona, Alexandria (OK, that's Africa).  Although,
notably, a number of those have "old port" districts but the main city
is on higher ground. And Rome and London were major ports, but inland.
Hmmm.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #113 of 126: Mark McDonough (mcdee) Mon 9 May 11 17:39
    
Yeah, but all those are on the Med, right?  The tsunami would have
been most intense along the coasts of Scandinavia & the British Isles
(apologies to Irish ancestors, but you know what I mean).  I doubt if
it would have made it into the Med at all through the Straits of
Gibraltar.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #114 of 126: Andrew Alden (alden) Mon 9 May 11 17:49
    
We're getting near the end of our exclusive discussion period, although no
one is going to shut us down and I'll keep replying as long as anyone keeps
asking. But I wanted to speak up for the scientist's sense of wonder when it
comes to earthquakes. It's a beautiful thing that Earth is physically active
and creates these energetic surges all the time. If Earth weren't alive in
this way, we would have no mountains, probably no land at all, very little
life that we would recognize, no mineral wealth -- no Earth.

And these seismic signals give us almost the only way to analyze the inside
of the planet deeper than drills can go. Like a doctor tapping your chest to
sense the condition of your lungs, seismologists can sift through the pops
and creaks and cracks and follow how their waves behave at all depths in th
planet. Their instruments get better, and the experiments they organize
using hundreds of seismographs give us the same unprecedentedly clear
pictures of the interior that massed telescopes give us of the heavens.

Seismologists will always have mixed feelings about the big events, which
crate so much misery yet yield strong and intriguing signals. Fortunately,
one promising avenue of research uses ambient seismic signals -- background
noise -- to do the kind of seismology that once took a good jolt. Over time,
this should allow seismologists to have less ambivalent feelings about large
earthquakes and have the same mix of dread and awe the rest of us feel. In
the meantime, maybe the rest of us can seek some of the curiosity and wonder
in the scientist's view of earthquakes.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #115 of 126: paralyzed by a question like that (debunix) Mon 9 May 11 19:07
    
Is it likely that there would be any new science coming out pretty
quickly after an event like this reveals the earth's innards anew, or
it that the kind of thing that takes years and years and many quakes to
realize?
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #116 of 126: Andrew Alden (alden) Mon 9 May 11 22:05
    
A magnitude 9 event is particularly good at exciting the extremely slow
oscillations that affect the entire planet. This kind of data is prized by
the handful of specialists who do refined modeling of deep Earth structure.
Of course, they may still be digesting similar data from Sumatra.

The immediate scientific results will center around the crust and shallow
mantle of Japan: how an event of this size took form in that tectonic
setting, and what the stress changes in the region may mean for other
earthquake-producing zones in Japan. A new piece of historical data has been
added to the catalog, and modelers will be trying new tricks and reassessing
older data in light of it. Engineers will know more about the dynamics of
earthquake shaking at the maximum magnitudes that can be realistically
planned for. Everyone -- first responders, emergency planners, insurers,
government agencies at all levels, media, construction firms and regulators,
and the common people all have much to learn from the March 11 quake, and
experts from around the world will be applying the same lessons to their own
countries. Considering the appalling death tolls of historical quakes, the
Tohoku quake was much less deadly than it could have been elsewhere. We can
all benefit.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #117 of 126: Teleological dyslexic (ceder) Tue 10 May 11 20:42
    
Sorry to come in so late, I do not know what year it was but I got
awakened in Manhattan city like a giant was shaking my bed, the
building etc.  The radio was out for half an hour... pets were upset as
were pictures on the walls.  Hard-rock shaker!  ;-} 

T
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #118 of 126: Teleological dyslexic (ceder) Tue 10 May 11 20:43
    
Thanks for being here!
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #119 of 126: Gail Williams (gail) Tue 10 May 11 21:52
    
Great stuff.  

I have a question, Alden.  One of the things I loved from geology text
books was the that there was an older scale that is used to compare
surface intensity, the thing we actually perceive on the ground.  I
know that a quake has one Magnitude and perhaps many local intensities,
but it is a wonderful way to describe what happens on the surface.

I love the use of "Did You Feel It?" questionaires in making
crowd-sourced shake maps.  With GPS-enabled devices it could become
even more precise in time, though now it is by zipcode.

Here's one sample of what I'm looking at:
 <
http://earthquake.usgs.gov/earthquakes/dyfi/events/ci/14978652/us/index.html>

What do you think of shake mapping for participatory quake reporting
and awareness? Is it of any use for science, too?
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #120 of 126: Andrew Alden (alden) Tue 10 May 11 22:17
    
ShakeMap is now considered as robust as traditional methods for making
intensity maps, Gail. And of course every person who fills in the form in
reporting their quake experience is aware of earthquakes in a way they
weren't before. It's like the people who light their flames at rock
concerts: a little thing for each person, but we create an impresive
communal event.

The other day I was thinking about the stadium experience called "the wave,"
where the people in one section of seats lift their arms simultaneously,
then "send" the signal to the next section over, launching a phenomenon that
can persist for quite a long time, circling the stadium many times. There
ought to be a version that a stadium full of seismologists could do,
simulating the several types of seismic waves in a visceral way. (No doubt
there's a blog post somewhere already.)
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #121 of 126: Jon Lebkowsky (jonl) Wed 11 May 11 06:17
    
As Andrew noted Monday, we're at the end of the "official" two week
run for this conversation. The next Inkwell conversation begins today,
but this conversation doesn't have to end as long as Andrew and other
are interested in continuing. In fact, I just ran across a couple of
news stories referring to a prediction that Rome will have a
significant earthquake today - many people are leaving Rome, per
http://www.bbc.co.uk/news/world-13357963. That might be worth
discussing, especially if there really is a severe earthquake in the
region today (as predicted by the late Raffaele Bendandi, who didn't
really pinpoint Rome).

Many thanks to Andrew and Mark for this informative, in-depth
discussion of earthquake and geology. This was an unusual discussion in
that we didn't have a book to focus on, but maybe one will emerge in
the wake of these discussions...
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #122 of 126: Andrew Alden (alden) Wed 11 May 11 11:50
    
No book, but my long-standing website at About.com
<http://geology.about.com/> amounts to one. I do my best to cover
earthquakes, volcanoes, tsunamis, rocks, minerals and the more advanced
topics in geology at a layperson-friendly level. And of course I'm around
the Well along with other folks with plenty of their own expertise, ready to
comment whenever something comes up.

If I have any advice today, it is to resolutely ignore and counterargue
stories like the supposed quake prediction for Rome. Earthquakes, and the
prospect of earthquakes, bring out the worst in people because they cannot
be controlled and cannot be predicted yet. We give them the same responses
we give to the prospect of death, taxes and other inevitabilities.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #123 of 126: Alan Fletcher (af) Wed 11 May 11 11:54
    
[ slip -- for non-well people, that means <alden> posted <122> while I
was composing this one. ]

1 dead after earthquake hits Spain
<http://www.cnn.com/2011/WORLD/europe/05/11/spain.earthquake.death/index.html?h
pt=T2>

[ Thanks for the discussion --- maybe you can come back to it when
there's a new event! ]


< A magnitude 9 event is particularly good at exciting the extremely
slow oscillations that affect the entire planet.

Wouldn't this lend some credence to the triggering of related
earthquakes, for example Simon Winchester's theories (and reports of a
sequence of major quakes before the SF 1906 event).
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #124 of 126: Andrew Alden (alden) Wed 11 May 11 12:02
    
Any connections between great events and later ones that they may trigger
are obscure and limited at best. Winchester is not a theorist, does not have
a good grasp of his subject, and doesn't express himself well except as a
barstool yarn-spinner. He really deserves the same share of attention as the
predicters, which is to say none.
  
inkwell.vue.406 : Andrew Alden on Earthquakes
permalink #125 of 126: Gail Williams (gail) Wed 11 May 11 12:30
    
Thanks, Andrew and all.  

For WELL-members who enjoyed this, you might add the <quake.> conf to
your list.  (It's quiet for a while, then all of a sudden it's active
and fascinating again. No wonder.)
  

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