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<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008>I recently read the attached report by Peter May (link
below) that some on the listserve may find interesting and may shed some light
on societal perspectives about seismic safety. The second and third
paragraphs of page 15 were of particular interest. Also, Bruce Bolt's quote
in Paragraph 2 on page 17 on general agreement on earthquake risk is
worth noting. I guess we are behind the "green building"
movement. Maybe society will begin to embrace seismic safety as much as
they do "green buildings". </SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008>Larry </SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008><FONT face="Times New Roman"><FONT face=Arial></FONT>
<P><BR></FONT><B><FONT face=Arial size=2>Lawrence P. Goldfarb,
P.E.</FONT></B><FONT face="Times New Roman"><BR></FONT><FONT face=Arial
size=2>CDM</FONT></P>
<P><FONT face=Arial size=2>Sr. Geotechnical Engineer</FONT><FONT
face="Times New Roman"> , Group Leader</P></FONT><FONT face=Arial size=2>
<P>3130 Fairview Park Drive</FONT><FONT face="Times New Roman"><BR></FONT><FONT
face=Arial size=2>Falls Church, VA 22042-4517</FONT><FONT
face="Times New Roman"><BR></P></FONT><FONT face=Arial size=2>
<P>Phone: (703) 485-8500</P>
<P>Direct: (703) 485-8434</P>
<P>Cell: (703) 408-7282</P>
<P>Fax: (</FONT><FONT face=Arial size=2>703) 698-1250</FONT><FONT face=Arial
size=2><BR></P></FONT><FONT face="Times New Roman"></FONT><FONT face=Arial
size=2>
<P>E-mail: goldfarblp@cdm.com</P></FONT></SPAN></FONT></DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008></SPAN></FONT> </DIV>
<DIV dir=ltr align=left><FONT face=Arial color=#0000ff size=2><SPAN
class=049173921-23022008><A
href="http://peer.berkeley.edu/publications/peer_reports/reports_2006/PEER612_MAY.pdf">http://peer.berkeley.edu/publications/peer_reports/reports_2006/PEER612_MAY.pdf</A></SPAN></FONT></DIV><BR>
<DIV class=OutlookMessageHeader lang=en-us dir=ltr align=left>
<HR tabIndex=-1>
<FONT face=Tahoma size=2><B>From:</B>
ceus-earthquake-hazards-bounces@geohazards.usgs.gov
[mailto:ceus-earthquake-hazards-bounces@geohazards.usgs.gov] <B>On Behalf Of
</B>Arthur D Frankel<BR><B>Sent:</B> Friday, February 22, 2008 1:28
PM<BR><B>To:</B> ceus-earthquake-hazards@geohazards.usgs.gov<BR><B>Subject:</B>
[CEUS-earthquake-hazards] reply to Ellis Krinitzsky<BR></FONT><BR></DIV>
<DIV></DIV><BR><FONT face=sans-serif size=2>Ellis,</FONT> <BR><BR><FONT
face=sans-serif size=2> 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. </FONT><BR><BR><FONT face=sans-serif size=2> 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. </FONT><BR><BR><FONT face=sans-serif size=2> 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."
</FONT><BR><FONT face=sans-serif size=2>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. </FONT><BR><BR><FONT
face=sans-serif size=2>-Art</FONT> <BR><BR><BR><BR><FONT face=sans-serif
size=2>Art Frankel<BR>U.S. Geological Survey<BR>MS 966, Box
25046<BR>DFC<BR>Denver, CO 80225<BR>phone: 303-273-8556<BR>fax:
303-273-8600<BR>email: afrankel@usgs.gov</FONT> <BR><BR><BR>
<TABLE width="100%">
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<TR vAlign=top>
<TD width="40%"><FONT face=sans-serif size=1><B>"Krinitzsky, Ellis L
ERDC-GSL-MS Emeritus" <Ellis.L.Krinitzsky@usace.army.mil></B>
</FONT>
<P><FONT face=sans-serif size=1>02/22/2008 08:40 AM</FONT> </P>
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<DIV align=right><FONT face=sans-serif size=1>To</FONT></DIV>
<TD><FONT face=sans-serif size=1>"Arthur D Frankel"
<afrankel@usgs.gov>, "Wang, Zhenming"
<zmwang@email.uky.edu></FONT>
<TR vAlign=top>
<TD>
<DIV align=right><FONT face=sans-serif size=1>cc</FONT></DIV>
<TD><FONT face=sans-serif
size=1><ceus-earthquake-hazards@geohazards.usgs.gov></FONT>
<TR vAlign=top>
<TD>
<DIV align=right><FONT face=sans-serif size=1>Subject</FONT></DIV>
<TD><FONT face=sans-serif size=1>RE: [CEUS-earthquake-hazards] FW:
reply to Joe Tomasello; buildings codes and earthquake
hazard</FONT></TR></TBODY></TABLE><BR>
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<TD></TR></TBODY></TABLE><BR></TR></TBODY></TABLE><BR><BR><BR><FONT
size=2><TT>Art,<BR><BR>I saw elsewhere you came to your values using a logic
tree.<BR><BR>Suppose you had two faults, one with a potential for M6, another
for M8. If<BR>you average them you have an M7. If you designed for that M7 and
you had an<BR>M8, you would be under designed. Yet the logic tree makes you do
exactly<BR>that. Plus other illogical moves.<BR><BR>You need to solve those
problems first.<BR><BR>Ellis <BR><BR>-----Original Message-----<BR>From:
ceus-earthquake-hazards-bounces@geohazards.usgs.gov<BR>[mailto:ceus-earthquake-hazards-bounces@geohazards.usgs.gov]
On Behalf Of<BR>Arthur D Frankel<BR>Sent: Tuesday, February 19, 2008 10:01
PM<BR>To: Wang, Zhenming<BR>Cc:
ceus-earthquake-hazards@geohazards.usgs.gov<BR>Subject: Re:
[CEUS-earthquake-hazards] FW: reply to Joe Tomasello; buildings<BR>codes and
earthquake hazard<BR><BR>Zhenming,<BR><BR> These two statements are not
contradictory, when taken in the context that<BR>I wrote them.<BR><BR> In
the quote from my response to my comment, I was referring to the
ground<BR>motions observed at any given location over time. At any particular
site the<BR>ground motions with a 2% chance of being exceeded in 50 years, will
occur, on<BR>average, once in 2500 years. As I said before, another way to
express this is<BR>that these ground motions have a 1/2500 chance of being
exceed each year.<BR><BR> The point of my recent email is that each time
an 1811-12 type earthquake<BR>occurs, there will be some locations that will
experience the 2%/50 ground<BR>motions or larger, because of the spatial
variability of ground motions. The<BR>set of sites that experience these
higher ground motions will likely be<BR>different for each occurrence of this
type of earthquake, because of the<BR>variability of ground motions from
earthquake to earthquake. This apparent<BR>temporal variability of ground
motions will occur even for successive<BR>earthquakes on the same fault, because
of differences in rupture propagation<BR>and slip on the fault from earthquake
to earthquake. <BR><BR>As you design buildings to ground motions with
lower probability levels, you<BR>are protecting a larger fraction of buildings
from the range of ground<BR>motions expected during the next 1811-12 type
earthquake.<BR><BR>Art Frankel<BR>U.S. Geological Survey<BR>MS 966, Box
25046<BR>DFC<BR>Denver, CO 80225<BR>phone: 303-273-8556<BR>fax:
303-273-8600<BR>email:
afrankel@usgs.gov<BR><BR><BR>-----ceus-earthquake-hazards-bounces@geohazards.usgs.gov
wrote: -----<BR><BR><BR><BR>
To:
"ceus-earthquake-hazards@geohazards.usgs.gov"<BR><ceus-earthquake-hazards@geohazards.usgs.gov><BR>
From: "Wang, Zhenming"
<zmwang@email.uky.edu><BR>
Sent by: ceus-earthquake-hazards-bounces@geohazards.usgs.gov<BR>
Date: 02/19/2008
07:34AM<BR> Subject:
[CEUS-earthquake-hazards] FW: reply to Joe Tomasello;<BR>buildings codes and
earthquake hazard<BR>
<BR> <BR><BR>
Here is another inconsistent
statement on the national seismic hazard<BR>maps.<BR><BR>
<BR><BR>
" You have the mistaken notion that 2%/50 values are
only observed<BR>once in 2500 years. This is flat out wrong. " <BR><BR>
<BR><BR>
In a response to our comment (Wang and
others, 2005) that was<BR>published on Seismological Research Letter (Frankel,
2005), the<BR>interpretation was "the ground motion with 2% PE in 50 years is
exceeded<BR>once, on average over 2,500 years, so that it has a 1/2500 annual
probability<BR>of being exceeded." <BR><BR>
<BR><BR>
<BR><BR>
<BR><BR> As
demonstrated earlier, for a single M7.7 earthquake with 500 year<BR>recurrence
interval in the New Madrid seismic zone, ground motion with<BR>2,500-year return
period (2% PE in 50 years) means there is about 20 percent<BR>probability that
ground motion will be exceeded if the M7.7 earthquake<BR>occurs. In other words,
if the ground motion with 2,500-year return period is<BR>selected for
engineering design, we has a confidence level of 80% (not being<BR>exceeded) if
the M7.7 earthquake occurs. <BR><BR>
<BR><BR>
Thanks. <BR><BR>
<BR><BR> Zhenming
<BR><BR>
<BR><BR>
<BR>________________________________<BR><BR><BR>
From:
ceus-earthquake-hazards-bounces@geohazards.usgs.gov<BR>[mailto:ceus-earthquake-hazards-bounces@geohazards.usgs.gov]
On Behalf Of<BR>Arthur D Frankel <BR>
Sent: Friday, February 15, 2008 1:50 PM <BR>
To: Joe Tomasello <BR>
Cc:
ceus-earthquake-hazards@geohazards.usgs.gov; mpetersen@usgs.gov <BR>
Subject: Re:
[CEUS-earthquake-hazards] reply to Joe Tomasello;<BR>buildings codes and
earthquake hazard <BR><BR>
<BR><BR>
<BR> Joe, <BR>
<BR>
I feel I need to reply to you on the bulletin
board, since you seem<BR>to want to keep this discussion going and you directly
ask me questions. My<BR>apologies to Paul Segal and others who are fed up with
this. <BR> <BR>
I guess you missed one
of the key points of my previous email. I<BR>said that the IBC values
(2/3 times the ground motions with 2% probability of<BR>exceedance in 50 years
[2%/50]) were probably experienced inMemphis during<BR>the 1811-12 earthquakes,
based on intensity data from those earthquakes. <BR>
<BR>
You have this mistaken notion that IBC values (2/3 times the
2%/50<BR>motions) are only observed once in a millenium. You have
the mistaken<BR>notion that 2%/50 values are only observed once in 2500 years.
This is flat<BR>out wrong. Some locations will experience 2/3 times
the 2%/50 ground<BR>motions during the next 1811-12 type earthquake. Some
locations will<BR>experience the 2%/50 ground motions during the next 1811-12
type earthquake.<BR>This is a simple consequence of the observed variability of
earthquake ground<BR>motions. <BR>
<BR>
As far as the magnitude issue you bring up, the USGS
uses the<BR>range of magnitudes that various seismologists have determined
for the<BR>1811-12 earthquakes from the intensity data. The central
values of these<BR>moment magnitude determinations range from 7.4-7.5
(Hough et al., 2000 in<BR>JGR) to 7.8 (Bakun and Hopper, 2004 in BSSA)
to 8.0-8.1 (Johnston, 1996 in<BR>Geophysical Journal). In the
national maps we use a logic tree to express<BR>this range, with a value of 7.7
given the highest weight. I used M7.7 in<BR>the scenario in my previous
email, because it is in the center of the range<BR>of magnitudes determined for
the 1811-12 earthquakes. I also gave results<BR>for a M7.4 earthquake.
<BR> <BR>
In the example in
my previous email, I placed the scenario<BR>earthquake where the current
seismicity trend for the New Madrid seismic zone<BR>is located. The closest
distance to downtown Memphis is about 60 km. <BR>
<BR>
-Art <BR>
<BR>
<BR> <BR>
<BR>
Art Frankel <BR>
U.S. Geological Survey <BR>
MS 966, Box 25046 <BR>
DFC <BR>
Denver , CO 80225 <BR>
phone: 303-273-8556 <BR>
fax: 303-273-8600 <BR>
email: afrankel@usgs.gov <BR>
<BR>
<BR><BR>
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