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New Madrid Fault_Brendan_BJS comments
- 1. The New Madrid Fault Brendan Ninneman
- 2. History Reelfoot Rift Failed breakup of Supercontinent Rodinia (750 million years ago) Sand Blows Formed about 4800 B.C. and 3500 B.C. Similar to New Madrid
- 3. Current Area Four-segment, zig-zag fault system 125 miles long Fault extends from Marked Tree, Arkansas to Cairo, Illinois Rocks in the region are harder, colder, dryer, and less fractured
- 4. Earthquakes of 1811-12 Strongest earthquake recorded east of Rocky Mountains Five major earthquakes (magnitude 7.0), 15 earthquakes (6.5-8.0), 189 earthquakes (5.0-6.5) Reelfoot Lake created
- 5. Worst Case $300 Billion in Direct Economic Loss (Three times worst than Phase I) 3,500 Fatalities 2.6 Million Households without power Bedrock In Downtowns St. Louis - 10 feet below surface Memphis - 3,000 feet below surface
- 6. Are We Ready? Short Answer: No City Buildings Monsanto Center
- 9. Summary The region is We are overdue for a earthquake the size of a 6.3 by 30 years Majority of buildings are not up to date on earthquake standards No change in the foreseeable future
Editor's Notes
- Crust in the New Madrid Area is weaker than much of the crust in the rest of the United States. Geologists call this an aulacogen (a scar or zone of weakness) Scientists do not know much history about the seismic zone since it is so far below the surface, explain later. Marianna sand blows predate paleoearthquakes attributed to NMFZ. Used the rock record to determine these.
- Earthquake is not on the surface (San Andreas). Hidden bellow 100-200 ft. thick layers of alluvium. Shake and damage are 20 times larger compared to California and most other seismic zones.
- Five earthquakes took place between December 16,1811 and February 7, 1812. Rang church bells on East Coast, cracked sidewalks in Washington D.C. James Madison, sitting president was awakened in the middle of the night. Two thousand more were felt by people, crude seismograph and personal journals Louisville, Kentucky, and Cincinnati, OH. (250 and 350 miles away respectively) Picture Landslide trench and ridge in the Chickasaw Bluffs east of Reelfoot Lake, Tennessee
- Minor shocks and tremors between releasing small amounts of energy Federal Emergency Management Agency (FEMA) (Phase I, 2008; Phase II, 2010) Phase One looked at possibilities if various segments erupted Fatalities belong to 2:00am scenario 715,000 Damaged Buildings Involves a complete rupture of the fault throughout the region Other studies project even worse Picture NMSZ liquefaction susceptibility of Evansville
- Cities are not ready. Until there is a loss of life, governments will not update the current earthquake standards. NGA - built in the early 1900s, mostly brick and concrete on the inside. Government workers work include analyze natural disasters (Haiti, 2010). Separate from the U.S. Geologic Survey. Monsanto Center - Built in 1997, designed to be “earthquake proof” with 41 base isolators placed beneath the building and mounted footings that reach to the bedrock (10 feet)
- This is an example of the base isolators that are found underneath the Monsanto Center. The building itself is floating on these base isolators.
- Well that's a shame