By Todd Hatton
Washington, D. C. – A new report from the US Geological Survey says the New Madrid earthquakes of 1811 and 1812 may not have been as powerful as history suggests. USGS seismologist Susan Hough says eyewitness accounts and photographs of ground damage indicate the tremor should be revised down to 6 point 8, one fourth as powerful as the current estimate of 7.2. Hough attributes the change to evidence of site amplification, where loose soil in areas like river valleys shakes more violently than areas on bedrock. According to the American Association for the Advancement of Science, the downgrade doesn't mean the New Madrid Seismic Zone isn t active. About 4,000 minor quakes have been recorded since 1974.