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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>We are discussing the basic understandings
on earthquakes and some assumptions that have been used in the USGS national
seismic hazard maps. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Are you saying that all these
understandings and assumptions are wrong? <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Are you saying that </span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'>an
observation can be counted as several events?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Thanks.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Zhenming<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
ceus-earthquake-hazards-bounces@geohazards.usgs.gov [mailto:ceus-earthquake-hazards-bounces@geohazards.usgs.gov]
<b><span style='font-weight:bold'>On Behalf Of </span></b>Stephen C Harmsen<br>
<b><span style='font-weight:bold'>Sent:</span></b> Thursday, February 07, 2008
11:34 AM<br>
<b><span style='font-weight:bold'>To:</span></b> Eugene S Schweig<br>
<b><span style='font-weight:bold'>Cc:</span></b>
ceus-earthquake-hazards@geohazards.usgs.gov;
ceus-earthquake-hazards-bounces@geohazards.usgs.gov<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re:
[CEUS-earthquake-hazards] alternative hazard maps</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
</span></font><font size=2 face=sans-serif><span style='font-size:10.0pt;
font-family:sans-serif'>While Buddy's response does point out many relevant
issues, I contend that Zhenming's question is not simple but is in fact
baffling.</span></font> <br>
<font size=2 face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'>How
often are ground motions observed depends on how many observers are present.
The populations of these cities increase with time, at least that is the trend
for a few centuries. Civil defense measures may evolve with time and we might
hope that before the next NMSZ major event occurs some effort will be made to
evacuate less seismically resistant buildings. People who live and work in
these identified buildings may leave these cities for awhile, so simple
population projections might not be valid. If we are talking about 200 years in
the future, we should hope that continued science and technology improvements
will lessen the number of observers at least the number of casualties. Those
who want to ride the wave should be welcomed to do so after sober assessment of
their odds. Then, there is the likelihood of several events in a short time
span. Does an observation of each count as one or as several? What about
observations of aftershocks? If the observer dies before he/she has a chance to
report, does his/her observation count? Do pets' observations count?</span></font>
<br>
<br>
<font size=2 face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'>In
the NMSZ events of 1811-1812 most people lived and worked in 1-story buildings
generally wood frame construction (how much sod?). Now, the built environment
is much different and the number of hostages to vagaries of tall building
response has increased. While there is considerable inertia to seismic
resistant design in many counties it is difficult to predict how adequate the
nation's and individual states' response to the seismic threat will be over the
next few centuries. The difficulty lies in the many societal pressures that
have been discussed in these various emails, what resources are dedicated to
which threats, and whose voice is heard. These are indeed unpredictable
factors. </span></font><br>
<font size=2 face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'><br>
Stephen Harmsen<br>
Research Physical Scientist<br>
USGS <br>
(303) 273 8567<br>
mailing address: USGS, <st1:place w:st="on"><st1:City w:st="on">Denver Federal
Center</st1:City>, <br>
<st1:State w:st="on">MS</st1:State></st1:place> 966, <st1:address w:st="on"><st1:Street
w:st="on">Box 25046</st1:Street>, <st1:City w:st="on">Denver</st1:City>, <st1:State
w:st="on">CO</st1:State> <st1:PostalCode w:st="on">80225</st1:PostalCode></st1:address><br>
<br>
USGS office (for overnight deliveries):<br>
<st1:address w:st="on"><st1:Street w:st="on">1711 Illinois Street</st1:Street>,
<st1:City w:st="on">Golden</st1:City>, <st1:State w:st="on">CO</st1:State> <st1:PostalCode
w:st="on">80401</st1:PostalCode></st1:address><br>
</span></font><br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal><b><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif;font-weight:bold'>Eugene S Schweig
<schweig@usgs.gov></span></font></b><font size=1 face=sans-serif><span
style='font-size:7.5pt;font-family:sans-serif'> </span></font><br>
<font size=1 face=sans-serif><span style='font-size:7.5pt;font-family:sans-serif'>Sent
by: ceus-earthquake-hazards-bounces@geohazards.usgs.gov</span></font> <o:p></o:p></p>
<p><font size=1 face=sans-serif><span style='font-size:7.5pt;font-family:
sans-serif'>02/07/2008 07:33 AM</span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
face=sans-serif><span style='font-size:7.5pt;font-family:sans-serif'>To</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>"ceus-earthquake-hazards@geohazards.usgs.gov"
<ceus-earthquake-hazards@geohazards.usgs.gov></span></font> <o:p></o:p></p>
</td>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
face=sans-serif><span style='font-size:7.5pt;font-family:sans-serif'>cc</span></font><o:p></o:p></p>
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style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
face=sans-serif><span style='font-size:7.5pt;font-family:sans-serif'>Subject</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>Re: [CEUS-earthquake-hazards] alternative
hazard maps</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span
style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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face="Times New Roman"><span style='font-size:12.0pt'><br>
<br>
<br>
</span></font><font size=2 face=sans-serif><span style='font-size:10.0pt;
font-family:sans-serif'><br>
Zhenming,</span></font> <br>
<font size=2 face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'><br>
While your question is simple, it is also misleading. If we could count
on M 7.7 earthquakes happenning every 500 years, and we could count on the
ground motions always be the same at each of these locations for a New Madrid
event, and if a repeat of 1811-1812 were the only thing that could cause that
level of ground motions at each location, our leaders could go to bed happy
that it would be at lest 200 hundred years before they had to start building
safe buildings. Sadly, none of this is true. We have little
information on the regularity of earthquake timing. We know there can be
significant variation in the ground motions generated by the same size
earthquake from even to event because of a number of factors. We also
know that other earthquakes besides a repeat of the 1811-1812 earthquakes may
contribute to the possibility of large ground motions, particularly with
increasing distance from New Madrid. So while the question is simple, the
answer is not, which I am sure you already know.</span></font> <br>
<font size=2 face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'><br>
Buddy</span></font> <font size=2 face=sans-serif><span style='font-size:10.0pt;
font-family:sans-serif'><br>
Fading into the Central U.S.Seismic Sunset</span></font> <font size=2
face=sans-serif><span style='font-size:10.0pt;font-family:sans-serif'><br>
__________________________________________________________________<br>
Eugene Schweig<br>
Chief Scientist<br>
Earth Surface Processes Team<br>
<st1:country-region w:st="on"><st1:place w:st="on">U.S.</st1:place></st1:country-region>
Geological Survey<br>
<br>
<st1:City w:st="on"><st1:place w:st="on">Denver</st1:place></st1:City> Office:<br>
MS980 Federal Center
(303)
236-5344<br>
<st1:place w:st="on"><st1:City w:st="on">Denver</st1:City>, <st1:State w:st="on">CO</st1:State>
<st1:PostalCode w:st="on">80225-0046</st1:PostalCode></st1:place>
Fax:
(303) 236-5690<br>
<br>
<st1:City w:st="on"><st1:place w:st="on">Memphis</st1:place></st1:City> office:
<br>
<st1:Street w:st="on"><st1:address w:st="on">3876 Central Ave., Ste. 2</st1:address></st1:Street>
(901) 678-4974<br>
<st1:place w:st="on"><st1:City w:st="on">MEMPHIS</st1:City>, <st1:State w:st="on">TN</st1:State>
<st1:PostalCode w:st="on">38152-3050</st1:PostalCode></st1:place>
Fax: (901)
678-4897<br>
___________________________________________________________________<br>
</span></font><br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal><b><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif;font-weight:bold'>"Wang, Zhenming"
<zmwang@email.uky.edu></span></font></b><font size=1 face=sans-serif><span
style='font-size:7.5pt;font-family:sans-serif'> <br>
Sent by: ceus-earthquake-hazards-bounces@geohazards.usgs.gov</span></font> <o:p></o:p></p>
<p><font size=1 face=sans-serif><span style='font-size:7.5pt;font-family:
sans-serif'>02/07/08 07:24 AM</span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>Arthur D Frankel <afrankel@usgs.gov>,
Seth Stein <seth@earth.northwestern.edu></span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>"ceus-earthquake-hazards@geohazards.usgs.gov"
<ceus-earthquake-hazards@geohazards.usgs.gov></span></font> <o:p></o:p></p>
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<p class=MsoNormal align=right style='text-align:right'><font size=1
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<p class=MsoNormal><font size=1 face=sans-serif><span style='font-size:
7.5pt;font-family:sans-serif'>Re: [CEUS-earthquake-hazards] alternative
hazard maps</span></font><o:p></o:p></p>
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face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
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<br>
</span></font><font size=2 color=navy face=Arial><span style='font-size:10.0pt;
font-family:Arial;color:navy'><br>
</span></font> <font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><br>
Here is a simple question for every one: If an M7.7 earthquake occurs every 500
years in the New Madrid seismic zone, how often will the ground motion
generated by that earthquake be observed in <st1:City w:st="on">Memphis</st1:City>,
<st1:City w:st="on">St. Louis</st1:City>, or <st1:City w:st="on"><st1:place
w:st="on">Paducah</st1:place></st1:City>?</span></font> <font size=2
color=navy face=Arial><span style='font-size:10.0pt;font-family:Arial;
color:navy'><br>
</span></font> <font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><br>
Thanks.</span></font> <font size=2 color=navy face=Arial><span
style='font-size:10.0pt;font-family:Arial;color:navy'><br>
</span></font> <font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><br>
Zhenming <br>
</span></font> <tt><font size=2 face="Courier New"><span style='font-size:
10.0pt'>_______________________________________________</span></font></tt><font
size=2 face="Courier New"><span style='font-size:10.0pt;font-family:"Courier New"'><br>
<tt><font face="Courier New">CEUS-Earthquake-Hazards mailing list</font></tt><br>
<tt><font face="Courier New">CEUS-Earthquake-Hazards@geohazards.usgs.gov</font></tt><br>
<tt><font face="Courier New">https://geohazards.usgs.gov/mailman/listinfo/ceus-earthquake-hazards</font></tt></span></font><o:p></o:p></p>
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