intraplate deformation and seismicity: implication for seismic hazard and risk estimates in the...
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![Page 1: Intraplate Deformation and Seismicity: Implication for Seismic Hazard and Risk Estimates in the Central United States Zhenming Wang Kentucky Geological](https://reader036.vdocuments.us/reader036/viewer/2022062500/56649e465503460f94b3acec/html5/thumbnails/1.jpg)
Intraplate Deformation and Seismicity: Implication for Seismic Hazard and Risk Estimates in the Central United States
Zhenming WangKentucky Geological Survey
University of KentuckyLexington, KY 40506
EarthScope Annual MeetingMonterey, CAMarch 27-29, 2007
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Outline
• Introduction
• Seismicity in the central United States
• Deformation in the central United States
• Implication for seismic hazard and risk assessments
• Summary
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Problems in Kentucky
1) Mr. David Mast (a staff member from KY congressman Ed Whitfield office): Why can I not build a regular two-story house in Paducah?
2) DOE will not get permit from Ky-EPA to build a landfill at PGDP for clean-up.3) Design ground motion for bridges will be much higher than those in CA 4) One of the main reasons that Kentucky lost the centrifuge facility ($2B) to Ohio.
San Francisco Paducah
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Problems in Memphis
“$100M seismic retrofit of Memphis VA hospital, removing nine floors, bringing it to California standard. Whether this makes sense depends on perspective.” – Stein and Tomasello (1995)
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Seismicity(Stein et al., 2003)
(Frankel et al., 1996)
For seismic hazard: M vs. MRI?
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Deformation (Stephane et al., 2005)
(Calais et al., 2006)
(Newman et al., 1999)
For seismic hazard: M vs. MRI?
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SFB: M7.8 or MMI VIII and greater vs. ~100 years MRICUS: M7.8 or MMI VIII and greater vs. 500~1,000 years MRIIf loss: $100B (same) (not easy to compare)
Seismic Hazard Comparisons: CUS vs. San Francisco Bay
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SFB: 39% PE in 50 years of M7.8 or MMI VII and greater CUS: 5~10% PE in 50 years M7.8 or MMI VII and greater
39% Vs. 5~10% for $100B loss in 50 yearsSFB has much higher exposure (people and properties)
This is why most of resources goes to CA for EARTHQUAKES
Seismic Risk Comparisons: CUS vs. San Francisco Bay
(Poisson model)
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Hazard and Risk Comparison in CUS: Earthquake, Flood, and Tornado
New Madrid earthquake
Miss. River Flood (1993)
Event 2005 Tornado
(Evansville)
~M7.7 ? Size F3
~500 ~100? τ (years) ~50?
~10% in 50 years/0.2% in 1 year
39%
in 50 years/1% in 1 year
Risk(probability)
~63% in 50 years/2% in 1
year
PGA/MMI/
PSA
Flood level Hazard at a specific
site
Wind speed
(200MPH)
$X $~15B Loss $~92M
x 50 Fatality 25
-1000
-500
0
500
1000
Acc
el (c
m/s
/s)
Strike Parallel
-1000
-500
0
500
1000Strike Normal
-1000
-500
0
500
1000Vertical
-50
0
50
Vel
ocity
(cm
/s)
-50
0
50
-50
0
50
10 20 30 40 50-20
-10
0
10
20
Dis
pl (c
m)
10 20 30 40 50-20
-10
0
10
20
Time (sec)10 20 30 40 50
-20
-10
0
10
20
529 1213 624
12 38 12
1.1 13 0.7
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(Schaefer, 2006)
Risk posed by several hazards to the dams along Ohio River
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Summary• It does not make sense that Paducah and Memphis
have to design the same level of ground motion (or even higher) as San Francisco
• In the central US, large earthquakes are of safety concern. Characterizing these large earthquakes is very important for seismic hazard and risk assessment, as well as policy consideration.
• It is very important that scientists (seismologists,
geologists, etc) communicate their research in a clear and understandable way.
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• “If an earthquake has a 1000-year recurrence interval, should a 1000-year return period be assigned the ground motion it generates at a site?”
– Return Period: “the mean time between occurrences of a certain ground motion at a site”