Is East Coast prepared for truly powerful quake?

GateHouse Media:  WASHINGTON (AP) — There were cracks in the Washington Monument and broken capstones 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 prompted swift inspections of many structures Wednesday, including bridges and nuclear plants. An accurate dam age estimate could take weeks, if not longer.

And many people will not be covered by insurance.

In a small Virginia city near the epicenter, the entire downtown business district was closed. School was canceled for two weeks to give engineers time to check out cracks in several buildings.

At the 555-foot Washington Monument, inspectors found several cracks in the pyramidion — the section at the top of the obelisk where it begins narrowing to a point.

A 4-foot crack was discovered Tuesday during a visual inspection by helicopter. It cannot be seen from the ground. Late Wednesday, the National Park Service announced that structural engineers had found several additional cracks inside the top of the monument.

Carol Johnson, a park service spokeswoman, could not say how many cracks were found but said three or four of them were “significant.” Two structural engineering firms that specialize in assessin g earthquake damage were being brought in to conduct a more thorough inspection on Thursday.

The monument, by far the tallest structure in the nation’s capital, was to remain closed indefinitely, and Johnson said the additional cracks mean repairs are likely to take longer. It has never been damaged by a natural disaster, including earthquakes in Virginia in 1897 and New York in 1944.

Tuesday’s 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 — at best — serious and expensive repairs.

At worst, it could be condemned. The façade 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.

Leman said he is insured, but some property owners might not be so lucky.
< br> The Insurance Information Institute said earthquakes are not covered under standard U.S. homeowners or business insurance policies, although supplemental coverage is usually available.

The institute says coverage for other damage that may result from earthquakes, such as fire and water damage from burst gas or water pipes, is provided by standard homeowners and business insurance policies in most states.

Cars and other vehicles with comprehensive insurance would also be protected.

The U.S. Geological Survey classified the quake as Alert Level Orange, the second-most serious category on its four-level scale. Earthquakes in that range lead to estimated losses between $100 million and $1 billion.

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 ne wer buildings could withstand a more serious earthquake. But, he added, questions remain about the older buildings that are common in a metropolis founded hundreds of years ago.

“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 natural disasters and terrorism.

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.
< br> Buildings constructed in Boston in recent decades had to follow stringent codes comparable to anything in California, said Vernon Woodworth, an architect and faculty member at the Boston Architectural College. New construction on older structures also must meet tough standards to withstand severe tremors, he said.

It’s a different story with the city’s older buildings. The 18th- and 19thcentury 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 on Tuesday 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 building standards regionally, he said.