Eric Duvall, cartographic technician, left, and Jeff Olsen, geodesist, both with the National Oceanic and Atmospheric Administration (NOAA) National Geodetic Survey, measures elevation on the National... more 
Eric Duvall, cartographic technician, left, and Jeff Olsen, geodesist, both with the National Oceanic and Atmospheric Administration (NOAA) National Geodetic Survey, measures elevation on the National Mall, with the Washington Monument in the background, Tuesday, March 13, 2012, in Washington. Government surveyors are collecting data around the Washington Monument and other sites on the National Mall that will reveal whether it has sunk or tilted since last year's earthquake. (AP Photo/Charles Dharapak) less 
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Associated Press | Photo By Charles Dharapak
Tue, Mar 13, 2012 7:01 PM EDT