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| Charles... |
 Posted: Mon Jul 20, 2009 9:24 pm |
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ScienceDaily (July 20, 2009) — The potential for a huge Pacific Ocean
tsunami on the West Coast of America may be greater than previously
thought, according to a new study of geological evidence along the
Gulf of Alaska coast.
The new research suggests that future tsunamis could reach a scale far
beyond that suffered in the tsunami generated by the great 1964
Alaskan earthquake. Official figures put the number of deaths caused
by the earthquake at around 130: 114 in Alaska and 16 in Oregon and
California. The tsunami killed 35 people directly and caused extensive
damage in Alaska, British Columbia, and the US Pacific region*.
<more> http://www.sciencedaily.com/releases/2009/07/090720083421.htm |
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| The Other Guy... |
| Posted: Mon Jul 20, 2009 11:26 pm |
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On Mon, 20 Jul 2009 20:24:43 -0700, Charles <ckraft at (no spam) SPAMTRAP.west.net>
wrote:
[quote:0f494d7139]ScienceDaily (July 20, 2009) — The potential for a huge Pacific Ocean
tsunami on the West Coast of America may be greater than previously
thought, according to a new study of geological evidence along the
Gulf of Alaska coast.
[/quote:0f494d7139]
Yeah, EVERYTHING could be worse than we expect.
Ho-Hum...
To reply by email, lose the Ks... |
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| Mike Williams... |
| Posted: Tue Jul 21, 2009 5:46 am |
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"The Other Guy" <KnewsKgnus at (no spam) gmail.com> wrote in message news:abka651com1br5jeos126id3fsh5eqqb43 at (no spam) 4ax.com...
On Mon, 20 Jul 2009 20:24:43 -0700, Charles <ckraft at (no spam) SPAMTRAP.west.net>
wrote:
[quote:75b72262a1]ScienceDaily (July 20, 2009) - The potential for a huge Pacific Ocean
tsunami on the West Coast of America may be greater than previously
thought, according to a new study of geological evidence along the
Gulf of Alaska coast.
Yeah, EVERYTHING could be worse than we expect.
Ho-Hum...
I thought the article was quite interesting (thanks, Charles). Though my recollection is that the tsunami of 1964 was already considered to be anomalously small for an undersea subduction quake of M9.2.[/quote:75b72262a1]
Mike Williams
Arroyo Grande, CA U.S. |
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| David Oberman... |
| Posted: Tue Jul 21, 2009 10:10 am |
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"Mike Williams" <miklwlms at (no spam) charter.net> wrote:
[quote:4c6e1a9ce8]Though my recollection is that the tsunami of 1964 was already considered to be anomalously small for an undersea subduction quake of M9.2.
[/quote:4c6e1a9ce8]
Do you mean "small" in the far field? Or small remotely AND locally?
(I'm assuming we're talking about the "main" quake tsunami & not the
slide/slump-generated local waves that knocked out Seward, Kodiak,
&c.)
____
All the pain of existence is shattered against
the immense delight of playing with it.
-- Richard Wagner, "Beethoven" (1870) |
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| Mike Williams... |
| Posted: Tue Jul 21, 2009 3:52 pm |
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"David Oberman" <doberman at (no spam) socal.rr.com> wrote in message news:dvpb65dh2ij904rbnrphitomes4qfvd24g at (no spam) 4ax.com...
"Mike Williams" <miklwlms at (no spam) charter.net> wrote:
[quote:eb580b76fb]Though my recollection is that the tsunami of 1964 was already considered to be anomalously small for an undersea subduction quake of M9.2.
[/quote:eb580b76fb]
Do you mean "small" in the far field? Or small remotely AND locally?
(I'm assuming we're talking about the "main" quake tsunami & not the
slide/slump-generated local waves that knocked out Seward, Kodiak,
&c.)
____
All the pain of existence is shattered against
the immense delight of playing with it.
-- Richard Wagner, "Beethoven" (1870)
Hi David,
I mean overall, locally and distant, exclusive of any secondary phenomena. I realize the wave did reach some pretty large heights and runup distances/heights in the very near-field, but, on the whole it seemed to be less than one would expect for that magnitude.
You may have heard the term "tsunami quake" - different from "tsunamigenic". It means a quake with some certain particulars (I don't recall the details) which make it particularly likely to generate a tsunami of large size vs.. magnitude ratio. I suspect the Good Friday quake was only marginally a tsunami quake. I think it's Gerard Fryer who has written and even posted here on the subject.
The January 1700 M 9.0 quake (estimated, of course), produced a significant tsunami in Japan. Maybe the Good Friday quake was just aimed wrong, or the tsunami was thwarted by local geography. I was 14 y.o. at the time and went to the beach cliffs in Santa Cruz to watch it. It was a real yawner.
Mike Williams
Arroyo Grande, CA U.S. |
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| Skywise... |
| Posted: Tue Jul 21, 2009 8:18 pm |
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| Mike Williams... |
| Posted: Tue Jul 21, 2009 11:06 pm |
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"Skywise" <into at (no spam) oblivion.nothing.com> wrote in message
news:eGu9m.72768$e11.47336 at (no spam) newsfe14.ams2...
[quote:5b8c875bad]"Mike Williams" <miklwlms at (no spam) charter.net> wrote in
news:hNq9m.42688$Ta5.34275 at (no spam) newsfe15.iad:
Hello Mike! Can you turn off HTML/MIME posting in your newsreader?
Your messages looks like raw HTML webpage code.
Usenet is intended to be pure text and many newsreaders do not
support HTML.
Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes?
[/quote:5b8c875bad]
You got it, Brian. My Outlook newsreader somehow switched to HTML while I
was trying, for the 12th time, to get it to properly indent and add brackets
to quoted text. It warned me I was sending in HTML, but I ignored that -
figuring that, by now, the majority of readers would have newsreaders
equipped for it. Maybe not. Anyway, I switched it back to plain text, and
give up trying to get the brackets. My work-around is to put them in myself
.. . . .
Mike Williams
"For every complex problem there is a simple solution. And it's wrong." |
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| Skywise... |
| Posted: Wed Jul 22, 2009 10:38 pm |
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| Belba Grubb... |
| Posted: Thu Jul 23, 2009 1:52 am |
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This is getting more publicity: "Wired Science" has an article on it,
too: http://www.wired.com/wiredscience/2009/07/tsunami/
Here's the key quote from abstract of the referenced January 2009
paper (via Science Direct at http://preview.tinyurl.com/kl9ue7 )
"For the first time, we present evidence that earthquakes [ca.] 900
and [ca.] 1500 years ago simultaneously ruptured adjacent segments of
the Aleutian megathrust and the Yakutat microplate, with a combined
area [some] 15% greater than 1964, giving an earthquake of greater
magnitude and increased tsunamigenic potential."
Gosh.
It's beyond me to know how they distinguished the deposits from those
that might have been left behind by a mass flow in the Aleutians like
those described in the June issue of the same periodical:
http://preview.tinyurl.com/ko59oj . That would undoubtedly have been
the measurement of "paleoseismic records preserved in coastal
sediments." Fascinating.
Barb
----------
Wired Science's "5 Atrocious Science Cliches":
http://www.wired.com/wiredscience/2009/07/blackholescience/ |
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| Belba Grubb... |
| Posted: Thu Jul 23, 2009 1:54 am |
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PS: In the last paragraph, should have said "the deposits from a
tsunami generated by a mass flow in the Aleutians like...."
B. |
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| Mike Williams... |
| Posted: Thu Jul 23, 2009 7:23 am |
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"Belba Grubb" <trungsisterfan at (no spam) yahoo.com> wrote in message
news:df135a2e-6563-4dee-8a49-f3f7c09dcf25 at (no spam) k30g2000yqf.googlegroups.com...
[quote:fcde3745e5]This is getting more publicity: "Wired Science" has an article on it,
too: http://www.wired.com/wiredscience/2009/07/tsunami/
Here's the key quote from abstract of the referenced January 2009
paper (via Science Direct at http://preview.tinyurl.com/kl9ue7 )
"For the first time, we present evidence that earthquakes [ca.] 900
and [ca.] 1500 years ago simultaneously ruptured adjacent segments of
the Aleutian megathrust and the Yakutat microplate, with a combined
area [some] 15% greater than 1964, giving an earthquake of greater
magnitude and increased tsunamigenic potential."
Gosh.
It's beyond me to know how they distinguished the deposits from those
that might have been left behind by a mass flow in the Aleutians like
those described in the June issue of the same periodical:
http://preview.tinyurl.com/ko59oj . That would undoubtedly have been
the measurement of "paleoseismic records preserved in coastal
sediments." Fascinating.
Barb
----------
Wired Science's "5 Atrocious Science Cliches":
http://www.wired.com/wiredscience/2009/07/blackholescience/
[/quote:fcde3745e5]
Hi Barb,
Don't you think they dated the deposits from widely separated locations, and
found those dates to be congruent? That would rule out such local phenomena
as slumps excepting, of course, very unlikely coincidences. Or am I missing
something?
Hey Brian, et al. - I figured out my quoting/bracketing problem. I've been
reading, and responding to, posts using the "preview pane" in Outlook. Turns
out that if I double-click on the post heading to open it in a separate
window, and reply from there, the bracketing is done correctly. At least I
hope it is . . .
Mike Williams
Arroyo Grande, CA U.S. |
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| Mike Williams... |
| Posted: Thu Jul 23, 2009 7:36 am |
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"Mike Williams" <miklwlms at (no spam) charter.net> wrote in message
news:hvZ9m.25116$YU5.21963 at (no spam) newsfe21.iad...
[quote:9dd698f33c]"Belba Grubb" <trungsisterfan at (no spam) yahoo.com> wrote in message
news:df135a2e-6563-4dee-8a49-f3f7c09dcf25 at (no spam) k30g2000yqf.googlegroups.com...
This is getting more publicity: "Wired Science" has an article on it,
too: http://www.wired.com/wiredscience/2009/07/tsunami/
Here's the key quote from abstract of the referenced January 2009
paper (via Science Direct at http://preview.tinyurl.com/kl9ue7 )
"For the first time, we present evidence that earthquakes [ca.] 900
and [ca.] 1500 years ago simultaneously ruptured adjacent segments of
the Aleutian megathrust and the Yakutat microplate, with a combined
area [some] 15% greater than 1964, giving an earthquake of greater
magnitude and increased tsunamigenic potential."
Gosh.
It's beyond me to know how they distinguished the deposits from those
that might have been left behind by a mass flow in the Aleutians like
those described in the June issue of the same periodical:
http://preview.tinyurl.com/ko59oj . That would undoubtedly have been
the measurement of "paleoseismic records preserved in coastal
sediments." Fascinating.
Barb
----------
Wired Science's "5 Atrocious Science Cliches":
http://www.wired.com/wiredscience/2009/07/blackholescience/
Hi Barb,
Don't you think they dated the deposits from widely separated locations,
and found those dates to be congruent? That would rule out such local
phenomena as slumps excepting, of course, very unlikely coincidences. Or
am I missing something?
Hey Brian, et al. - I figured out my quoting/bracketing problem. I've been
reading, and responding to, posts using the "preview pane" in Outlook.
Turns out that if I double-click on the post heading to open it in a
separate window, and reply from there, the bracketing is done correctly.
At least I hope it is . . .
Mike Williams
Arroyo Grande, CA U.S.
[/quote:9dd698f33c]
Barb,
I took a closer look at the earlier Science Direct article (synopsis) on
Aleutian mass flows, and see now that some of the slumps are believed to be
capable of producing large, oceanic tsunamis. So even the dates of deposits
resulting from those slumps, at widely separated locations, may well be
congruent also. BUT - the referenced earthquakes are in the very recent past
(900 and 1500 years ago). Though the full article is not accessible, I
suspect the largest slumps, capable of producing very large tsunami occur on
a multi-millennial time scale. So, again, I think the deposits referenced in
the later article, if from widely separated locations, can be safely assumed
to be earthquake-generated.
What say you?
Mike Williams
Arroyo Grande, CA U.S. |
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| Skywise... |
| Posted: Thu Jul 23, 2009 1:52 pm |
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"Mike Williams" <miklwlms at (no spam) charter.net> wrote in
news:hvZ9m.25116$YU5.21963 at (no spam) newsfe21.iad:
[quote:6310cd62ac]Hey Brian, et al. - I figured out my quoting/bracketing problem.
[/quote:6310cd62ac]
Looks great to me.
I never understood why M$ takes it upon themselves to break standards.
Or how they continue to be so $ucce$$ful selling products with such
broken standards. Actually.... I do know. But I don't feel like
getting on my soapbox.
ANYWAY.....
A question comes to mind now. Just what could be the theoretical
maximum magnitude for an Aleutian quake? Could it be bigger than
the 9.4/9.5 Chilean quake?
Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
Seismic FAQ: http://www.skywise711.com/SeismicFAQ/SeismicFAQ.html
Quake "predictions": http://www.skywise711.com/quakes/EQDB/index.html
Sed quis custodiet ipsos Custodes? |
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| David Oberman... |
| Posted: Thu Jul 23, 2009 4:44 pm |
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Skywise <into at (no spam) oblivion.nothing.com> wrote:
[quote:5984aca9dc]A question comes to mind now. Just what could be the theoretical
maximum magnitude for an Aleutian quake? Could it be bigger than
the 9.4/9.5 Chilean quake?
[/quote:5984aca9dc]
Is it a simple case of rupture length, or can other factors ... uh,
factor in?
Say one subduction zone fault ruptures a given length & creates an
M9.0. Can another fault rupture a length two-thirds that length &
still generate an M9.5 -- if, say, the displacement is big enough?
____
In the history of art, late works are catastrophes.
-- Adorno |
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| Mike Williams... |
| Posted: Thu Jul 23, 2009 9:37 pm |
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"David Oberman" <doberman at (no spam) socal.rr.com> wrote in message
news:8qph65d54ltvm6jrjri28hb342c70ah0l6 at (no spam) 4ax.com...
[quote:2aa09296d9]Skywise <into at (no spam) oblivion.nothing.com> wrote:
A question comes to mind now. Just what could be the theoretical
maximum magnitude for an Aleutian quake? Could it be bigger than
the 9.4/9.5 Chilean quake?
Is it a simple case of rupture length, or can other factors ... uh,
factor in?
Say one subduction zone fault ruptures a given length & creates an
M9.0. Can another fault rupture a length two-thirds that length &
still generate an M9.5 -- if, say, the displacement is big enough?
[/quote:2aa09296d9]
You seem to have two of the factors, Dave - almost. Rather than rupture
length it should be total area of the fault whereon slip took place, and
displacement is probably a good enough term; though I think seismologists
would say "average amount of slip" on that surface. The third factor, for
moment magnitude at least, is rock rigidity.
So - I dunno what the theoretical maximum might be that for an Aleutian
quake. But I shouldn't think it could match the Chilean one. The rupture
length for Chile was huge, close to a thousand miles. I don't think the
Aleutians could match that distance. Both the proposed Aleutian quake and
the Chile quake are subduction quakes. So, barring the Aleutians slipping
over a much greater area (L. X W.), and having much greater rock strength, I
don't think the Aleutians could beat the Chile quake in magnitude. But to
answer your question, Dave, I think that yes - in your scenario that second
quake _could_ have a larger magnitude.
I seem to recall reading somewhere that the maximum plausible earthquake due
to tectonic forces (i.e. not including meteor or comet impacts) for the
Earth would be below M10.
Maybe a professional could help us out here . . .
[quote:2aa09296d9]In the history of art, late works are catastrophes.
-- Adorno
The same could be said of war and wildland firefighting, with a slightly[/quote:2aa09296d9]
different definition of "late works".
Mike Williams
Arroyo Grande, CA |
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