‘Old’ East Coast Shows Cracks After Earthquake

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There was a crack in the Washington Monument, and capstones were broken at the National Cathedral. In the District of Columbia suburbs, some people stayed in shelters because of structural concerns at their apartment buildings.

A day after the East Coast’s strongest earthquake in 67 years, inspectors assessed the damage and found that most problems were minor. But the shaking raised questions about whether this part of the country, with its older architecture and inexperience with seismic activity, is prepared for a truly powerful quake.

The 5.8 magnitude quake felt from Georgia north to Canada on August 23 prompted inspections of many structures, including bridges and nuclear plants. An accurate damage estimate could take weeks, if not longer. Many claims will not be covered by insurance.

At the 555-foot Washington Monument, crews found a 4-inch crack in the side of the monument’s pyramidium — the section at the top of the obelisk where it begins narrowing to a point. The damage was discovered during a visual inspection by helicopter. It cannot be seen from the ground.

The quake was centered about 40 miles northwest of Richmond, 90 miles south of Washington and 3.7 miles underground. In the nearby town of Mineral, Va., Michael Leman knew his Main Street Plumbing & Electrical Supply business would need serious and expensive repairs. At worst, it could be condemned. The facade had become detached from the rest of the building, and daylight was visible through a 4- to 6-inch gap that opened between the front wall and ceiling.

“We’re definitely going to open back up,” Leman said. “I’ve got people’s jobs to look out for.” Leman said he is insured.

In Culpeper, Va., about 35 miles from the epicenter, walls had buckled at the old sanctuary at St. Stephen’s Episcopal Church, which was constructed in 1821 and drew worshippers including Confederate Gens. Robert E. Lee and J.E.B. Stuart. Heavy stone ornaments atop a pillar at the gate were shaken to the ground. A chimney from the old Culpeper Baptist Church built in 1894 also tumbled down.

At the Washington National Cathedral, spokesman Richard Weinberg said the building’s overall structure remains sound and damage was limited to “decorative elements.” Massive stones atop three of the four spires on the central tower broke off, crashing onto the roof. Repairs were expected to cost millions of dollars — an expense not covered by insurance.

“Every single portion of the exterior is carved by hand, so everything broken off is a piece of art,” Weinberg said. “It’s not just the labor, but the artistry of replicating what was once there.”

Other major cities along the East Coast that felt the shaking tried to gauge the risk from another quake.

A few hours after briefly evacuating New York City Hall, Mayor Michael Bloomberg said the city’s newer buildings could withstand a more serious earthquake. But, he added, questions remain about the older buildings. “We think that the design standards of today are sufficient against any eventuality,” he said. But “there are questions always about some very old buildings. … Fortunately those tend to be low buildings, so there’s not great danger.”

An earthquake similar to the one in Virginia could do billions of dollars of damage if it were centered in New York, said Barbara Nadel, an architect who specializes in securing buildings against disasters.

The city’s 49-page seismic code requires builders to prepare for significant shifting of the earth. High-rises must be built with certain kinds of bracing, and they must be able to safely sway at least somewhat to accommodate for wind and even shaking from the ground, Nadel said.

Buildings constructed in Boston in recent decades had to follow stringent codes comparable to anything in California, said Vernon Woodworth, a faculty member at the Boston Architectural College. New construction on older structures also must meet tough standards, he said.

It’s a different story with the city’s older buildings. The 18th- and 19th-century structures in Boston’s Back Bay, for instance, were often built on fill, which can liquefy in a strong quake, Woodworth said. Still, there just aren’t many strong quakes in New England. The last time the Boston area saw a quake as powerful as the one that hit Virginia was in 1755, off Cape Ann, to the north. A repeat of that quake would likely cause deaths, Woodworth said. Still, the quakes are so infrequent that it’s difficult to weigh the risks versus the costs of enacting tougher standards, he said.