Scant Quake Preparation Found East of the Rockies : Science: Although the probability of a large tremor is low, experts see significant peril to pipelines, transportation systems and utility lines.

Despite an appreciable risk of destructive earthquakes in the United States east of the Rockies, woefully little has been done in those regions to safeguard transportation systems, pipelines and overhead utility links from quake damage, according to a report by scientists.

The danger “is larger than we might expect,” said Klaus Jacob, senior research scientist at the Lamont-Doherty Geological Observatory at Columbia University and one of five earthquake engineers participating in a briefing at the annual meeting of the American Society of Civil Engineers. The group met last week in New York City.

“The probability of a large earthquake east of the Rockies is low, but it is not that low,” Jacobs reported. “Every three years, (there is) a magnitude 5, every 22 years a magnitude 6. A magnitude 7 or greater has a 50% chance in 100 years. . . .

“When close to major metropolitan areas like New York City, a large earthquake would cause a catastrophe never before experienced in U.S. history.”

Thomas O’Rourke, professor of civil engineering at Cornell University, said that one critical area of concern “is the vulnerability of the buried lifeline network in New York.”

For example, he declared, a recent survey showed that 90% of the water and 50% of the gas were distributed in the metropolis through cast-iron mains, which he described as “a brittle material with a relatively low threshold for ground movement damage.”

Masanobu Shinozuka of Princeton University, director of the National Center for Earthquake Engineering Research, contrasted seismic-oriented lifeline building codes that have existed for years in the West with seismic retrofitting that is only now getting under way in the East.

He said the result is that the probability of failure of vital systems “is not necessarily low” in the East even though the big earthquakes are fewer and farther between.

One municipality that has begun upgrading its systems is Memphis, Tenn, which is relatively close to the site of the destructive New Madrid, Mo., earthquakes of 1811-12, which, if recurring now, could devastate parts of several states in the mid-Mississippi River valley.

O’Rourke said that three petroleum transmission lines, carrying 400 million barrels a year, and 11 gas transmission lines, carrying about 4 trillion cubic feet per year, are at risk from soil liquefaction alone in the New Madrid earthquake zone.

He added that research has shown parts of the New York area are underlain by deposits of glacial lake clay, which, while stiffer and stronger than those found under San Francisco or Mexico City, could still amplify earthquake waves and cause serious destruction.

Quake Risk Ratings

The American Society of Civil Engineers fears that, unlike in California, construction standards in low risk states do not allow for big earthquakes. According to the group, the area east of the Rockies is at risk of a 5.0-magnitude quake every three years.

Source: American Society of Civil Engineers