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Science Forum Index » Geology - Earthquakes Forum » 4.0 quake in Utah and mine collapse
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| Skywise |
 Posted: Mon Aug 06, 2007 11:37 am |
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| Weatherlawyer |
| Posted: Mon Aug 06, 2007 7:06 pm |
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Skywise wrote:
Someone remind me, have we had a plane crash anywhere yet? |
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| Damon Hill |
| Posted: Mon Aug 06, 2007 8:30 pm |
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Skywise <into@oblivion.nothing.com> wrote in
news:13bejigaion5h45@corp.supernews.com:
They now seem to think the earthquake WAS the mine collapse.
That's pretty impressive.
Alas, I don't hold out much hope for the six missing miners.
--Damon |
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| rick++ |
| Posted: Tue Aug 07, 2007 8:02 am |
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Quote: They now seem to think the earthquake WAS the mine collapse.
That's pretty impressive.
At this lower magnitude it probably did not register on a enough
seismographs to best determine whether it had a fault source
(radiation pattern). There are single station methods of discerning
non-fault quakes based on the initial pules and power ratios of
various phases. This seismic event is just above the threshhold
of global nuclear detection network (M3.5) which is designed to
discern
non-fault seismic events. |
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| Aidan Karley |
| Posted: Wed Aug 08, 2007 6:50 am |
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In article <13bejigaion5h45@corp.supernews.com>, Skywise wrote:
morning ... that rescue attempts had been suspended for fear of an
earthquake. I assume that the actual reason was that there was a series
of aftershocks going on.
Good luck to the guys in the wet and dark.
--
Aidan Karley, FGS
Aberdeen, Scotland
Message written at Wed, 08 Aug 2007 09:59 +0100, now I'm back on
shore. |
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| Mike Williams |
| Posted: Wed Aug 08, 2007 8:12 am |
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"Aidan Karley" <name1_name2@email.provider.invalid> wrote in message
news:VA.00001433.0a2f2425@email.provider.invalid...
Quote: In article <13bejigaion5h45@corp.supernews.com>, Skywise wrote:
4.0 quake in Utah, about 2:48am local time...
http://earthquake.usgs.gov/eqcenter/recenteqsus/Quakes/uu00007535.php
....causing a mine to collapse. Six miners unaccounted for.
Ah, that accounts for the confusing report on the news this
morning ... that rescue attempts had been suspended for fear of an
earthquake. I assume that the actual reason was that there was a series
of aftershocks going on.
Good luck to the guys in the wet and dark.
At the USGS link you provided, as of this Wednesday morning, they (USGS)
state in the "Summary" section; "The United States Geological Survey
recorded one seismic event with a magnitude of 3.9 at 02:48 AM MDT on August
6, 2007. This event did not have the characteristics of a typical, natural
occurring earthquake."
There is no mention of any aftershocks.
Mike W.
93420
Quote:
--
Aidan Karley, FGS
Aberdeen, Scotland
Message written at Wed, 08 Aug 2007 09:59 +0100, now I'm back on
shore.
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| rick++ |
| Posted: Wed Aug 08, 2007 9:01 am |
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NEIC determined the Utah seismic events are not
from fault quakes. Mostly like the mine collapses. |
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| George |
| Posted: Wed Aug 08, 2007 11:16 am |
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"rick++" <rick303@hotmail.com> wrote in message
news:1186581707.118959.155510@g4g2000hsf.googlegroups.com...
Quote: NEIC determined the Utah seismic events are not
from fault quakes. Mostly like the mine collapses.
Do you have a link to a web page on their site where they discuss this?
I've noted several "aftershocks" at the NEIC site, with no comment on this
issue at all, at least, not where the tremors are reported.
George |
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| rick++ |
| Posted: Wed Aug 08, 2007 6:50 pm |
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Scientists, Executive Clash Over Quake
Aug 8 09:27 AM US/Eastern
By ALICIA CHANG
AP Science Writer
LOS ANGELES (AP) - Did an earthquake cause a Utah coal mine to cave
in, or did the mine collapse trigger the tremors?
A fierce dispute erupted over that question Tuesday, with a top mine
executive declaring on national television that he has the science to
prove a quake caused the collapse. But seismologists said their
instruments recorded shaking from the cave-in and not a natural
temblor.
Scientists believe the seismic waves in the area of the Crandall
Canyon mine were "the signature of the collapse and that the collapse
was not caused by an earthquake," said James W. Dewey, a seismologist
at the National Earthquake Information Center in Golden, Colo.
Scientists have not ruled out a natural earthquake since the region
surrounding the mine is seismically active, and they do not know the
exact time the mine collapsed.
But, Dewey said, "the data we have seen seem more consistent with the
collapse being the cause of the 'earthquake' rather than the other way
around."
On Monday, University of Utah seismographs recorded seismic waves of
3.9 magnitude near the mine. At least 10 aftershocks were felt more
than 24 hours after the collapse, with the strongest registering 2.2
magnitude.
Scientists say quakes caused by mine collapses tend to occur at
shallower depths and at different frequencies than natural
earthquakes.
The first motions of the Utah disturbance indicated a downward
movement consistent with a collapse, scientists said. If it was a
natural quake, it would have produced up and down motions on the
seismograms. The quake occurred anywhere from 2,000 to 8,500 feet
underground.
Mine officials insisted Monday's accident was caused by a natural
disaster.
"This was caused by an earthquake, not something that Murray
Energy ... did or our employees did or our management did," an irate
Robert E. Murray, chairman of mine owner Murray Energy Corp. of
Cleveland, said at a televised news conference. "It was a natural
disaster. An earthquake. And I'm going to prove it to you."
The company released a statement saying the depth of the earthquake
occurred in a region that was 3,500 feet deeper than where the miners
were.
The company also claimed the shaking lasted four minutes. Utah and
USGS scientists don't know exactly how long the shaking lasted, but
they said a 3.9 magnitude quake would cause jolts of just a few
seconds.
By contrast, the 9.0 magnitude quake in 2004 in the Indian Ocean
caused six minutes of shaking, USGS geophysicist John Bellini said.
There have been numerous examples of mine collapses triggering ground
vibrations sometimes confused with quakes. The USGS has recorded at
least seven such instances since 1994, including last year's collapse
of an abandoned mine in Virginia that registered a 4.3 magnitude.
Although mining activities have been shown to produce quakes, the
opposite is rare. Scientists say it's unusual for a temblor to damage
a mine unless it was a big one. In 1976, a 7.8 magnitude quake in
China wreaked havoc on coal mines beneath the city of Tangshan.
There are no recorded cases in Utah's history of a natural quake
triggering a mine collapse, said Walter Arabasz, director of the
University of Utah's seismograph stations.
The Crandall Canyon mine is built into a mountain in the rugged Manti-
La Sal National Forest, 140 miles south of Salt Lake City, in a
sparsely populated area. The region is crisscrossed with geologic
faults, and in 1988, a 5.2 magnitude temblor struck 25 miles southeast
of the mine. |
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| Aidan Karley |
| Posted: Wed Aug 08, 2007 9:32 pm |
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In article <bjjui.48162$YL5.3462@newssvr29.news.prodigy.net>, Mike Williams
wrote:
Quote: At the USGS link you provided, as of this Wednesday morning, they (USGS)
state in the "Summary" section; "The United States Geological Survey
recorded one seismic event with a magnitude of 3.9 at 02:48 AM MDT on August
6, 2007. This event did not have the characteristics of a typical, natural
occurring earthquake."
There is no mention of any aftershocks.
Yes, this evening's tech news carries that the mine owners are claiming
that the earthquake caused the collapse (and would therefore absolve them from
responsibility) while the USGS are saying "that doesn't look like a natural
quake". Which makes me think that the ambulance-chasers are in town, and the
ambulance-chaser-chasers have been on the phone to the mine management.
And no news of people coming out blinking in the daylight. Not good.
--
Aidan Karley, FGS
Aberdeen, Scotland
Message written at Thu, 09 Aug 2007 02:42 +0100, now I'm back on shore. |
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| rick++ |
| Posted: Thu Aug 09, 2007 9:37 am |
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Quote: Yes, this evening's tech news carries that the mine owners are claiming
that the earthquake caused the collapse (and would therefore absolve them from
responsibility) while the USGS are saying "that doesn't look like a natural
quake".
Unfortunately, just about everything the mine owner has said about the
situtation
has not been truthful so far- the "earthquake", mine saftey record,
the type of
mining being done when the accident occurred, etc. He also said
there was
lots of oxygen and saftey equipement for trapped people. I hope that
will be
an exception to the general pattern of truthfulness ... |
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| Nosterill |
| Posted: Mon Aug 13, 2007 9:46 am |
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On Aug 8, 5:16 pm, "George" <geo...@yourservice.com> wrote:
Quote: "rick++" <rick...@hotmail.com> wrote in message
news:1186581707.118959.155510@g4g2000hsf.googlegroups.com...
NEIC determined the Utah seismic events are not
from fault quakes. Mostly like the mine collapses.
Do you have a link to a web page on their site where they discuss this?
I've noted several "aftershocks" at the NEIC site, with no comment on this
issue at all, at least, not where the tremors are reported.
Could the "aftershocks" be secondary mine collapses? Maybe not an
indicator of a natural earthquake. |
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| Weatherlawyer |
| Posted: Mon Aug 13, 2007 1:19 pm |
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On Aug 13, 3:46 pm, Nosterill <fladg...@hotmail.com> wrote:
Quote:
Could the "aftershocks" be secondary mine collapses?
Probably.
In different states. Hence the terms:
United Mines of America and:
Tell it to the re:mines. |
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| Belba Grubb |
| Posted: Fri Aug 17, 2007 2:26 am |
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Well, now we have the second tragedy Thursday, and I found this in the
current Yahoo! story about it. What on earth is a mountain bump and
how common are these? What causes the pressure? This isn't the place
to ask why the rescuers weren't prepared for such an event once it had
been determined to be the cause of the August 6 collapse.
"Authorities said the cave-in was caused by a mountain bump,
which commonly refers to pressure inside the mine that shoots
coal from the walls with great force. Seismologists say such an
event caused the Aug. 6 cave-in that trapped six men inside the
central Utah mine.
Thursday's bump at 8:39 p.m. showed up as a magnitude 1.6
seismic event at University of Utah seismograph stations in
Salt Lake City, said university spokesman Lee Siegel."
Full story: http://news.yahoo.com/s/ap/20070817/ap_on_re_us/utah_mine_collapse
Barb
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If it weren't for the rocks in its bed, the stream would have no
song.
-- Carl Perkins
The violets in the mountains have broken the rocks.
-- Tennessee Williams |
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| Belba Grubb |
| Posted: Fri Aug 17, 2007 2:56 am |
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