After an earthquake in Mineral, VA, damaged the massive stone obelisk, extensive repairs were needed. Part of that process involved wrapping the structure in scafolding. Some $15 million dollars and a year later, repairs were finally completed this May (2014).
The government office tasked with knowing the exact coordinates and dimensions of the monument took this as an opportunity to have a survey crew resurvey the monument. When last surveyed in 1999, the monument was 555 feet, 5 1/8 inches.
According to Ben Sherman of the National Geodic Survey in an NPR article, the survey is part of an ongoing program to monitor the monument that began as far back as 1901. The monument is located on the National Mall, land that the Tiber Creek once flowed through until it was filled in by a landfill. “So there is the possibility of land sinking over time,” Sherman told NPR correspondants.
The National Geodetic Survey crew climbed to the top of the monument to place special sensors and GPS equipment. With the combination of ground-based laser measurements and satelite data, they will spend several months crunching numbers to see what if any movement in the monument has occurred.
Since the completion of the survey, no new height has been certified.