Quake protection needed for homes in many US cities
As older housing in the nation's urban areas becomes more attractive and many downtown areas sprout new high-rise buildings, specialists in earthquake research see a danger that building codes in many of these areas lack earthquake safety requirements.
Most American cities cannot afford to ignore earthquakes simply because "we have never had one," says Robert Sockwell, director of the American Institute of Architects (AIA) Research Corporation multi-hazard design project for seismic safety. At least 39 states have "significant potential" for quakes, he says.
The Northeast, the upper Mississippi Valley, and the Southeast experience frequent quakes, although they often lack the intensity of California quakes, according to "Earthquake History of the United States," an annual federal publication.
Many public officials feel that except for areas such as California, earthquake codes are unnecessary because seismic disturbances are rare in their areas.
Says Mr. Sockwell, they simply complain, "Too expensive!" -- a sentiment echoed by many private developers.
Specialists add that the worst quakes in US history occurred not in California but in Missouri. Three violent tremors in New Madrid, Mo., in 1811 and 1812 changed the course of the Mississippi River.
"Feeling your house shaking under your feet is traumatic, especially if you have no idea such a rumble could occur," says Warner Howe, chairman of the Building Code Advisory Board of Memphis, Tenn. He was refering to a July 27 earthquake centered in mid-Kentucky. "Historically, we have no record of an earthquake ever occurring in mid-Kentucky."
The tremor affected thousands of people in 14 states, including 40,000 baseball fans at a ball park in Detroit.
A member of the Applied Technical Council (ATC), commissioned by the National Science Foundation and the National Bureau of Standards to develop a model building code emphasizing earthquake safety, Mr. Howe adds, "I am not suggesting that every community push through some hasty earthquake safety program.
"We [in Memphis] see no necessity of building codes designed for California and based on the California experience to be used in Memphis," Howe says. But he adds that quake protection should be a "high priority item" in local and state building codes.
Boston has adopted earthquake provisions as part of its building code, although only four major earthquakes have struck New England since 1620, says Sockwell.
"If an earthquake of any degree of severity should strike, most Boston structures would be unable to withstand the pressure," says Prof. Daniel L. Schodek of the Harvard University Architectural Department. "Most American cities would face a similar dilemma in case of a quake. Boston's masonry stock would crumble, but its wooden structures and its code-approved buildings most likely would survive."
He and fellow professor Urs P. Gauchat are examining the seismic vulnerability of housing in Boston. Such housing poses "a dilemma faced by many major cities in the Northeast: what to do with a socially desirable large stock of existing housing . . . built prior to the advent of recent codes with earthquake-design provisions."
Upgrading aging structures is a major problem not only in cities such as Boston, but in San Francisco and Los Angeles, where regulations for older buildigns have not been implemented, says Robert V. Whitman, vice-president of the Earthquake Engineering Research Institute.
William J. LeMessurier, a planning engineer in Cambridge, Mass., says that designing for seismic safety is necessary as more insurance firms and the federal government demand these safeguards whenever they are involved in a project.
Costs of earthquake protection for new construction are "reasonable" if planned in advance, he says. An increase of only 1 percent has been factored into the cost of new structures under the Boston law, he says.