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Intraplate Deformation and Seismicity: Implication for Seismic Hazard and Risk Estimates in the Central United States. Zhenming Wang Kentucky Geological Survey University of Kentucky Lexington, KY 40506 EarthScope Annual Meeting Monterey, CA March 27-29, 2007. Outline. Introduction
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Intraplate Deformation and Seismicity: Implication for Seismic Hazard and Risk Estimates in the Central United States Zhenming Wang Kentucky Geological Survey University of Kentucky Lexington, KY 40506 EarthScope Annual Meeting Monterey, CA March 27-29, 2007
Outline • Introduction • Seismicity in the central United States • Deformation in the central United States • Implication for seismic hazard and risk assessments • Summary
Problems in Kentucky San Francisco Paducah • Mr. David Mast (a staff member from KY congressman Ed Whitfield office): Why can I not build a regular two-story house in Paducah? • 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.
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)
Seismicity (Stein et al., 2003) (Frankel et al., 1996) For seismic hazard: M vs. MRI?
Deformation (Stephane et al., 2005) (Calais et al., 2006) (Newman et al., 1999) For seismic hazard: M vs. MRI?
Seismic Hazard Comparisons: CUS vs. San Francisco Bay SFB: M7.8 or MMI VIII and greater vs. ~100 years MRI CUS: M7.8 or MMI VIII and greater vs. 500~1,000 years MRI If loss: $100B (same) (not easy to compare)
Seismic Risk Comparisons: CUS vs. San Francisco Bay (Poisson model) 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 years SFB has much higher exposure (people and properties) This is why most of resources goes to CA for EARTHQUAKES
Hazard and Risk Comparison in CUS: Earthquake, Flood, and Tornado
Risk posed by several hazards to the dams along Ohio River (Schaefer, 2006)
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.
“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”