Engineers have begun examining the exterior of one of Washington's most well-known landmarks: the Washington Monument, which was damaged in an earthquake last month.

An engineer strapped into a harness and secured by ropes began the inspection at the peak of the nearly 170-meter obelisk on Tuesday. Workers are expected later to rappel down the sides of the monument to get an up-close look at the stone blocks that make up the structure.

The monument has been closed to visitors since the 5.8 magnitude earthquake that struck the U.S. east coast August 23. Officials say numerous cracks and chips of stone were found inside, and the tip of the monument is also visibly cracked.

The National Park Service says storms that hit the area since then may have caused additional damage to the monument.

But the superintendent of of the National Mall and Memorial Parks says the monument is “structurally sound and not going anywhere.”

The park service says it hopes its assessment of the obelisk will be completed by mid-October.

On Monday the park service released security-camera video taken inside the monument during the quake. The video shows the initial jolt and several minutes of shaking while visitors scramble down the stairs to safety.

Experts say the monument's elevator system was also damaged in the quake. No one was seriously injured.

The earthquake was the largest to strike the eastern part of the United States since 1944, shaking the U.S. capital as well as towns and cities up and down the East Coast.

The Washington Monument is also one of Washington's older attractions. It was completed more than a century ago, in 1884.