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Unformatted text preview: Lecture #24: New Madrid Fault System and Earthquakes in Kentucky (Abbott, pp. 171-177) Know the years of the four major New Madrid Earthquakes Four great earthquakes struck near New Madrid, Missouri between December, 1811 and February, 1812. Two of them occurred on December 16, one on January 23, and the last on February 7 (Figure 7.18, p. 174; Figure 7.19, p. 175). The moment magnitudes of the four earthquakes were estimated at 7.0-7.5 (p. 174). Between December 16, 1811 and March 15, 1812, Jared Brooks, an amateur seismologist living in Louisville, KY, recorded 1,874 separate earthquakes (p. 171). The four main earthquakes produced numerous deep cracks in the earth around the town of New Madrid. Liquefaction (Lecture #8) features were common. The earthquakes released hydrogen sulfide gas from decaying organic matter in subsurface soils (p. 173). Chimneys toppled as far away as Ohio, Alabama and Louisiana. Church bells rang in Boston. Because the crust in the eastern part of the US is less fractured and cooler, destructive seismic waves can travel over longer distances (Figure 7.17, p. 174). Lexington was in a fairly high destruction zone during the 1811-1812 earthquakes (about VIII on Mercalli Scale) (Figure 7.19, p. 175; Table 4.4, p. 98). The number of causalities from the New Madrid earthquakes is unknown. Since 1812, St. Louis, Memphis, and other cities have become heavily populated and many buildings in the cities around the...
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This note was uploaded on 07/14/2011 for the course GLY 150 taught by Professor Henke during the Spring '08 term at Kentucky.
- Spring '08