Beyond the Obvious: Beyond the Obvious: National Econom ic I m pact - PowerPoint PPT Presentation

Beyond the Obvious: Beyond the Obvious: National Econom ic I m pact National Econom ic I m pact of a Likely New Madrid of a Likely New Madrid Earthquake Earthquake J. David Rogers, Ph.D., P.E., R.G. Karl F. Hasselm ann Hasselm ann Chair in Geological Engineering Chair in Geological Engineering Karl F. Natural Hazards Mitigation I nstitute Natural Hazards Mitigation I nstitute University of Missouri- - Rolla Rolla University of Missouri Earthquakes: Mean Business Earthquakes: Mean Business February 2 , 2 0 0 7 February 2 , 2 0 0 7

Question # 1 Question # 1 W hy should all Am ericans be W hy should all Am ericans be concerned about the im pacts of concerned about the im pacts of a New Madrid Earthquake? a New Madrid Earthquake? Earthquakes: Mean Business February 2 , 2 0 0 7

Hurricane Hurricane Katrina Katrina New Orleans • Ask 1 1 ,0 0 0 form er Ford Motor Co. em ployees about the im pacts of Hurricane Katrina on SUV sales U.S. Dams U.S. Dams Earthquakes: Mean Business February 2 , 2 0 0 7

Question # 2 Question # 2 How Could the St. Louis Area How Could the St. Louis Area Be Dam aged by an Earthquake Be Dam aged by an Earthquake 2 0 0 kilom eters Aw ay? 2 0 0 kilom eters Aw ay? Earthquakes: Mean Business February 2 , 2 0 0 7

Active Midw est Seism ic Zones � New Madrid Seismic New Madrid Seismic Zone rediscovered in Zone rediscovered in 1973 NRC study of West 1973 NRC study of West Memphis power plant Memphis power plant Wabash Valley Seismic � Wabash Valley Seismic � Zone generated M 5+ Zone generated M 5+ quakes in 1968 and 1987; quakes in 1968 and 1987; initially suspected in initially suspected in 1993 and accepted in 1993 and accepted in 2004 2004 South Central Illinois � South Central Illinois � spawned a M 5+ quakes spawned a M 5+ quakes in 1838, 1857, and 1891. in 1838, 1857, and 1891. Initially recognized in Initially recognized in 1999 1999 Earthquakes: Mean Business February 2 , 2 0 0 7

The 1 8 9 5 M6 .0 Charleston, MO earthquake Earthquakes: affected an area 2 0 X greater than an equivalent Mean Business m agnitude quake in California February 2 , 2 0 0 7

SHAKI NG I NTENSI TY versus DI STANCE Conclusion: Don’ ’t use charts t use charts Conclusion: Don generated with seismic data generated with seismic data taken from California ! taken from California ! Earthquakes: Midwest quakes are less frequent, but much more lethal than Midwest quakes are less frequent, but much more lethal than Mean Business California quakes because there is less damping less damping of seismic energy. of seismic energy. February 2 , 2 0 0 7 California quakes because there is

Question # 3 Question # 3 W hat is the Most Likely W hat is the Most Likely Earthquake W e Can Expect in Earthquake W e Can Expect in the Here and Now ; not 3 0 0 the Here and Now ; not 3 0 0 years from now ? years from now ? Earthquakes: Mean Business February 2 , 2 0 0 7

Recurrence I ntervals for Recurrence I ntervals for New Madrid Earthquake Events* New Madrid Earthquake Events Magnitude Recurrence I nterval 4 .0 1 4 Months 5 .0 1 0 – 1 2 Years 6 .0 7 0 – 9 0 Years 7 .0 2 5 4 – 5 0 0 Years 5 5 0 – 1 2 0 0 Years 8 .0 * based on existing data; always subject to update and revision Earthquakes: Mean Business February 2 , 2 0 0 7

MOST LI KELY QUAKE MOST LI KELY QUAKE • I n our lifetim es, the m ost likely earthquake to im pact St. Louis w ould be som ething sim ilar to the Magnitude 6 .0 Charleston, MO quake of 1 8 9 5 , w hich has a recurrence frequency of 7 0 + / - 1 5 years ( overdue since 1 9 8 0 ) . • I t could em anate from either the New Madrid Zone or the W abash Valley Fault Zone, or from South Central I llinois. Earthquakes: Mean Business February 2 , 2 0 0 7

Question # 4 Question # 4 W hat is the Econom ic I m pact of W hat is the Econom ic I m pact of Soil Liquefaction? Soil Liquefaction? Earthquakes: Mean Business February 2 , 2 0 0 7

Recent sand blow s dot the landscape surrounding New Madrid, MO, testifying to Earthquakes: Mean Business m assive liquefaction February 2 , 2 0 0 7

LI QUEFACTI ON or “QUI CK SAND” CONDI TI ON Liquefaction is a failure mechanism by which is a failure mechanism by which Liquefaction cohesionless materials (sand and silt) lose shear materials (sand and silt) lose shear cohesionless strength when the pore water pressure equals the strength when the pore water pressure equals the effective confining stress. It is usually limited to effective confining stress. It is usually limited to the upper 50 feet and typically occurs in silt, sand the upper 50 feet and typically occurs in silt, sand and fine gravel. and fine gravel. Earthquakes: Mean Business February 2 , 2 0 0 7

Liquefaction Liquefaction Potential Potential Liquefaction is predicted is predicted Liquefaction in the Missouri River in the Missouri River Flood Plain for a Flood Plain for a Magnitude 6.8 quake Magnitude 6.8 quake from South Central from South Central Illinois and Wabash Illinois and Wabash Valley Seismic Zones. Valley Seismic Zones. Liquefaction to depths Liquefaction to depths of 18 m predicted for of 18 m predicted for Magnitudes > 6.5 Magnitudes > 6.5 Earthquakes: Mean Business February 2 , 2 0 0 7

Liquefaction Often Liquefaction Often I m pacts Bridges I m pacts Bridges • Though supported on steel and concrete piles respectively, these bridges both failed due to • Bridge failures during liquefaction of April 1 9 9 1 M7 .5 Costa Rica earthquake foundation m aterials, w hich tilted the piles • Fiber optic cables strung across bridges w ould also be severed Earthquakes: Mean Business February 2 , 2 0 0 7

Question # 5 Question # 5 W hy Are Old Lakes and Filled W hy Are Old Lakes and Filled Ground I m portant Factors in Ground I m portant Factors in Predicting Ground Shaking Predicting Ground Shaking I ntensity? I ntensity? Earthquakes: Mean Business February 2 , 2 0 0 7

This 1 7 9 6 m ap show s the spatial distributions of Earthquakes: oxbow s, cutoffs, and islands in the river floodplains Mean Business around St. Louis. February 2 , 2 0 0 7

Overlay of 1 9 0 8 Mississippi River Map Overlay of 1 9 0 8 Mississippi River Map Overlay Overlay information on information on historic maps – – historic maps in this case, old in this case, old oxbow lakes and oxbow lakes and cutoffs that cutoffs that have since been have since been Earthquakes: infilled infilled Mean Business February 2 , 2 0 0 7

Map Overlays Using Map Overlays Using Geographical I nform ation Geographical I nform ation System s System s • The spatial positions of the 1 9 0 8 lakes in the Mississippi River floodplain are overlain on m odern m aps of the area, to gain a better perspective on Briefer(s) Name(s) w hich areas are on filled ground; w hich m ight be February 2, 2007 subject to asym m etric site response Earthquakes: Mean Business February 2 , 2 0 0 7

Detail of Detail of Overlay Overlay • About half of the freew ay interchange betw een I nterstate 2 5 5 and I llinois Route 3 plots over one of the old cutoff lakes show n on the 1 9 0 8 m ap. • The different geologic conditions beneath either side of the interchange could be expected to foster asym m etric site response problem s Earthquakes: Mean Business February 2 , 2 0 0 7

Mississippi River Mississippi River Flood Plain Flood Plain • One of the m ost im portant One of the m ost im portant • GI S m ap products in flood GI S m ap products in flood plains along m ajor channels is plains along m ajor channels is a rendering of prehistoric a rendering of prehistoric channels channels • These channels tend to These channels tend to • develop one upon another, in develop one upon another, in spatially com plex patterns spatially com plex patterns • Note bedrock narrow s at Note bedrock narrow s at • Carondelet and position of the Carondelet and position of the m ain channel, hugging the m ain channel, hugging the w estern bank w estern bank Earthquakes: Mean Business February 2 , 2 0 0 7

Question # 6 Question # 6 How W ill the I ntensity of How W ill the I ntensity of Shaking Vary From One Area to Shaking Vary From One Area to Another Around St. Louis? Another Around St. Louis? Earthquakes: Mean Business February 2 , 2 0 0 7

Shaking I ntensity is Controlled by a factor called ‘Seism ic Site Response’ The type, depth and size of fault, com bined w ith physical properties of crust and geophysical properties of overlying surficial soils, all com bine Earthquakes: Mean Business to affect site response. February 2 , 2 0 0 7

Site response is used to describe the fundam ental period of vibration and lateral forces generated by a typical Earthquakes: Mean Business earthquake at any particular site. February 2 , 2 0 0 7

Effect of Soil Thickness on Peak Ground Acceleration (PGA) Magnitude 6.8 quake emanating from South Central Illinois Earthquakes: Mean Business at 110 km February 2 , 2 0 0 7

Effect of Soil Effect of Soil Thickness Thickness on RESPONSE on RESPONSE SPECTRA SPECTRA Earthquakes: Mean Business February 2 , 2 0 0 7