[CEUS-earthquake-hazards] Question-
WrightLa at usa.redcross.org
WrightLa at usa.redcross.org
Tue Feb 26 07:57:05 MST 2008
With respect to designs, I am curious to see what each person on the
list
would answer to the following-
Assume that you are designing a blood processing center for the Memphis
Tennessee area which will serve approximately 10% of the US population.
You are being asked to provide design standard requirements for this
facility on which 10% of the United States population will depend for
blood products.
The base facility is being designed for a 45 year useful life
What seismic standard will you use?
Why?
Laurence M. Wright
Senior Project Engineer
Manufacturing Engineering
202-303-4457 (o)
202-549-5843 (c)
> -----Original Message-----
> From: ceus-earthquake-hazards-bounces at geohazards.usgs.gov
[mailto:ceus-
> earthquake-hazards-bounces at geohazards.usgs.gov] On Behalf Of
> Krinitzsky,Ellis L ERDC-GSL-MS Emeritus
> Sent: Monday, February 25, 2008 10:42 AM
> To: Arthur D Frankel; ceus-earthquake-hazards at geohazards.usgs.gov
> Subject: Re: [CEUS-earthquake-hazards] reply to Ellis Krinitzsky
>
> Art,
>
> What I am saying is you can't account for uncertainty by probability,
> because
> you have too little data. It is easy by the deterministic method to
get a
> worst case (mean plus sigma) and design safely. With your probability,
you
> don't know what you have.
>
> I'd like to see you admit that one method is better than another for
> certain
> purposes.
>
> For structures that are critical (the consequences of failure are
> intolerable) you should use the deterministic method.
>
> Ellis
>
>
>
> -----Original Message-----
> From: ceus-earthquake-hazards-bounces at geohazards.usgs.gov
> [mailto:ceus-earthquake-hazards-bounces at geohazards.usgs.gov] On Behalf
Of
> Arthur D Frankel
> Sent: Friday, February 22, 2008 12:28 PM
> To: ceus-earthquake-hazards at geohazards.usgs.gov
> Subject: [CEUS-earthquake-hazards] reply to Ellis Krinitzsky
>
>
> Ellis,
>
> I don't think the example you cite is applicable to the case of the
> logic
> tree we use for New Madrid magnitudes. In our logic tree we are
trying to
> account for the uncertainty in the magnitude of characteristic
(1811-12
> type)
> earthquakes in the New Madrid source zone.
>
> In your example with two faults, a probabilistic hazard assessment
would
> use the range of magnitudes specific for each fault. It does not
average
> the
> magnitude between the two faults.
>
> In your earlier email, you expressed doubt about determining the
rates
> of
> large earthquakes by extrapolating the rates of smaller earthquakes
using
> a
> "b-line."
> This is not what is done for the New Madrid characteristic earthquakes
> (1811-12 type earthquakes). The average recurrence rate for the
1811-12
> type earthquakes is determined from the dating of sand blows (see
Tuttle
> et
> al., 2002 BSSA), which shows that previous such events occurred around
> 1450
> and 900 A.D.
>
> -Art
>
>
>
> Art Frankel
> U.S. Geological Survey
> MS 966, Box 25046
> DFC
> Denver, CO 80225
> phone: 303-273-8556
> fax: 303-273-8600
> email: afrankel at usgs.gov
>
>
>
> "Krinitzsky, Ellis L ERDC-GSL-MS Emeritus"
> <Ellis.L.Krinitzsky at usace.army.mil>
>
> 02/22/2008 08:40 AM To
> "Arthur D Frankel" <afrankel at usgs.gov>, "Wang, Zhenming"
> <zmwang at email.uky.edu>
> cc
> <ceus-earthquake-hazards at geohazards.usgs.gov>
> Subject
> RE: [CEUS-earthquake-hazards] FW: reply to Joe Tomasello; buildings
codes
> and earthquake hazard
>
>
>
>
>
>
> Art,
>
> I saw elsewhere you came to your values using a logic tree.
>
> Suppose you had two faults, one with a potential for M6, another for
M8.
> If
> you average them you have an M7. If you designed for that M7 and you
had
> an
> M8, you would be under designed. Yet the logic tree makes you do
exactly
> that. Plus other illogical moves.
>
> You need to solve those problems first.
>
> Ellis
>
> -----Original Message-----
> From: ceus-earthquake-hazards-bounces at geohazards.usgs.gov
> [mailto:ceus-earthquake-hazards-bounces at geohazards.usgs.gov] On Behalf
Of
> Arthur D Frankel
> Sent: Tuesday, February 19, 2008 10:01 PM
> To: Wang, Zhenming
> Cc: ceus-earthquake-hazards at geohazards.usgs.gov
> Subject: Re: [CEUS-earthquake-hazards] FW: reply to Joe Tomasello;
> buildings
> codes and earthquake hazard
>
> Zhenming,
>
> These two statements are not contradictory, when taken in the
context
> that
> I wrote them.
>
> In the quote from my response to my comment, I was referring to the
> ground
> motions observed at any given location over time. At any particular
site
> the
> ground motions with a 2% chance of being exceeded in 50 years, will
occur,
> on
> average, once in 2500 years. As I said before, another way to express
this
> is
> that these ground motions have a 1/2500 chance of being exceed each
year.
>
> The point of my recent email is that each time an 1811-12 type
> earthquake
> occurs, there will be some locations that will experience the 2%/50
ground
> motions or larger, because of the spatial variability of ground
motions.
> The
> set of sites that experience these higher ground motions will likely
be
> different for each occurrence of this type of earthquake, because of
the
> variability of ground motions from earthquake to earthquake. This
apparent
> temporal variability of ground motions will occur even for successive
> earthquakes on the same fault, because of differences in rupture
> propagation
> and slip on the fault from earthquake to earthquake.
>
> As you design buildings to ground motions with lower probability
levels,
> you
> are protecting a larger fraction of buildings from the range of ground
> motions expected during the next 1811-12 type earthquake.
>
> Art Frankel
> U.S. Geological Survey
> MS 966, Box 25046
> DFC
> Denver, CO 80225
> phone: 303-273-8556
> fax: 303-273-8600
> email: afrankel at usgs.gov
>
>
> -----ceus-earthquake-hazards-bounces at geohazards.usgs.gov wrote: -----
>
>
>
> To: "ceus-earthquake-hazards at geohazards.usgs.gov"
> <ceus-earthquake-hazards at geohazards.usgs.gov>
> From: "Wang, Zhenming" <zmwang at email.uky.edu>
> Sent by: ceus-earthquake-hazards-
> bounces at geohazards.usgs.gov
> Date: 02/19/2008 07:34AM
> Subject: [CEUS-earthquake-hazards] FW: reply to Joe
> Tomasello;
> buildings codes and earthquake hazard
>
>
>
> Here is another inconsistent statement on the national
> seismic hazard
> maps.
>
>
>
> " You have the mistaken notion that 2%/50 values are
only
> observed
> once in 2500 years. This is flat out wrong. "
>
>
>
> In a response to our comment (Wang and others, 2005)
that
> was
> published on Seismological Research Letter (Frankel, 2005), the
> interpretation was "the ground motion with 2% PE in 50 years is
exceeded
> once, on average over 2,500 years, so that it has a 1/2500 annual
> probability
> of being exceeded."
>
>
>
>
>
>
>
> As demonstrated earlier, for a single M7.7 earthquake
with
> 500 year
> recurrence interval in the New Madrid seismic zone, ground motion with
> 2,500-year return period (2% PE in 50 years) means there is about 20
> percent
> probability that ground motion will be exceeded if the M7.7 earthquake
> occurs. In other words, if the ground motion with 2,500-year return
period
> is
> selected for engineering design, we has a confidence level of 80% (not
> being
> exceeded) if the M7.7 earthquake occurs.
>
>
>
> Thanks.
>
>
>
> Zhenming
>
>
>
>
> ________________________________
>
>
> From:
ceus-earthquake-hazards-bounces at geohazards.usgs.gov
> [mailto:ceus-earthquake-hazards-bounces at geohazards.usgs.gov] On Behalf
Of
> Arthur D Frankel
> Sent: Friday, February 15, 2008 1:50 PM
> To: Joe Tomasello
> Cc: ceus-earthquake-hazards at geohazards.usgs.gov;
> mpetersen at usgs.gov
> Subject: Re: [CEUS-earthquake-hazards] reply to Joe
> Tomasello;
> buildings codes and earthquake hazard
>
>
>
>
> Joe,
>
> I feel I need to reply to you on the bulletin board,
> since
> you seem
> to want to keep this discussion going and you directly ask me
questions.
> My
> apologies to Paul Segal and others who are fed up with this.
>
> I guess you missed one of the key points of my
previous
> email. I
> said that the IBC values (2/3 times the ground motions with 2%
probability
> of
> exceedance in 50 years [2%/50]) were probably experienced inMemphis
during
> the 1811-12 earthquakes, based on intensity data from those
earthquakes.
>
> You have this mistaken notion that IBC values (2/3
> times
> the 2%/50
> motions) are only observed once in a millenium. You have the
mistaken
> notion that 2%/50 values are only observed once in 2500 years. This is
> flat
> out wrong. Some locations will experience 2/3 times the 2%/50
ground
> motions during the next 1811-12 type earthquake. Some locations will
> experience the 2%/50 ground motions during the next 1811-12 type
> earthquake.
> This is a simple consequence of the observed variability of earthquake
> ground
> motions.
>
> As far as the magnitude issue you bring up, the
USGS
> uses
> the
> range of magnitudes that various seismologists have determined for
the
> 1811-12 earthquakes from the intensity data. The central values of
these
> moment magnitude determinations range from 7.4-7.5 (Hough et al.,
2000 in
> JGR) to 7.8 (Bakun and Hopper, 2004 in BSSA) to 8.0-8.1 (Johnston,
1996
> in
> Geophysical Journal). In the national maps we use a logic tree to
express
> this range, with a value of 7.7 given the highest weight. I used
M7.7 in
> the scenario in my previous email, because it is in the center of the
> range
> of magnitudes determined for the 1811-12 earthquakes. I also gave
results
> for a M7.4 earthquake.
>
> In the example in my previous email, I placed the
> scenario
> earthquake where the current seismicity trend for the New Madrid
seismic
> zone
> is located. The closest distance to downtown Memphis is about 60 km.
>
> -Art
>
>
>
>
> Art Frankel
> U.S. Geological Survey
> MS 966, Box 25046
> DFC
> Denver , CO 80225
> phone: 303-273-8556
> fax: 303-273-8600
> email: afrankel at usgs.gov
>
>
>
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