Is the Washington Monument sinking?

Is the Washington Monument tilting? Is it sinking?

A team of surveyors is measuring the massive obelisk to determine for sure whether the memorial still stands straight at 555 feet.

For the past week, staffers from the National Oceanic and Atmospheric Administration’s Geodetic Survey have been working atop the iconic structure’s topmost point, studying the more than century-old landmark to see if it has sunk farther into the ground or is listing to one side as a result of either the passage of time or the effects of the August 2011 earthquake that rattled the region.

“There’s no reason to suspect the height to be any different. There’s no reason to believe anything has changed,” said Dru Smith, chief geodesist for the survey. “But you don’t know until you check.”

Mr. Smith said the survey was done at the request of the National Park Service. Official numbers — and any changes — will likely be announced in about a month.

The eight-man survey crew is able to do their job thanks to the scaffolding that currently encases the entire monument, allowing access to the topmost point of the structure.

“The chance to measure the peak was one we couldn’t pass up,” Mr. Smith said.

Crews began erecting the scaffolding around the monument in late spring so that repairs could be made to the exterior of the obelisk, which was damaged during the 5.8-magnitude quake. The powerful jolt shook loose mortar and small stones and cracked a portion of the angled part at the top of the monument, known as the pyramidion.

Last year, the National Geodetic Survey measured the grounds at the foot of the memorial and found no evidence the enormous structure had sunk or been knocked off kilter.

While Mr. Smith would not give a prediction on the measurements, he said if they come back different from historical numbers it would likely be the result of more accurate technology.

Surveyors have scaled the monument several times since its official public opening in 1888, and with each visit new and improved surveying and GPS equipment has been used to get the most accurate measurements, Mr. Smith said.

“We want to make sure everybody’s maps line up with each other, and our job is to provide that foundation,” he said.

NOAA survey technician Don Breidenbach was enlisted to design a stand to sit atop the monument’s topmost point and hold the surveying equipment, which includes a GPS and a machine that measures angles and distances.

“It was an honor to begin with just to get up there,” the South Dakota resident said Thursday. “It was an amazing sight from up there. Usually the only way you get that view is to look down out an airplane window.”

This week marked the beginning of the end for the survey team, as the Park Service began the removal of the scaffolding. Park Service officials said it could take about three months to remove the scaffolding.

The monument itself is scheduled to reopen in the spring of 2014.