The Paducah Sun
The Paducah Sun
Paducah, Kentucky
Tuesday, October 07, 2003

Study: Area not a great quake risk
New buildings in the region are subject to design standards that exceed those of California where far more earthquakes occur

By Joe Walker jwalker@paducahsun.com--270.575.8650
Schmidt


Based on six months of increased ground monitoring, a new Kentucky Geological Survey study suggests that the active faults of the New Madrid Seismic Zone may not extend into the Jackson Purchase.

The findings contrast higher hazard assessments by the U.S. Geological Survey that flowed into tougher building codes for the Paducah area. The codes are a major factor in economic development because they make it more difficult and expensive to design and erect structures — such as buildings, bridges and roads — to be earthquake-resistant. Higher seismic risk also means higher insurance premiums.

The new study argues that as a result of the federal views, new buildings are subject to design standards that are overly strict and even exceed those of California where far more earthquakes occur.

Funded by $115,000 from the Paducah-based Kentucky Consortium for Energy and Environment, an arm of the state's New Economy initiative, the survey team upgraded three monitoring stations and added eight new ones in western Kentucky.

Results gained from January through June showed that only one Purchase area earthquake took place — on June 6 centered in Bardwell. That magnitude 4 tremor had the same intensity but was only about a tenth as deep as an April 30 quake in Blytheville, Ark., in the center part of the New Madrid zone, the study says.

Experts with the state survey say the data support their long belief that the Purchase area faults are shallower and less risky than in the New Madrid zone. Because more data are needed to draw a conclusion, the survey will ask the General Assembly for $500,000 to add more monitoring stations and scientists. From that, they hope to either lobby the USGS to change its conservative risk maps or produce their own maps.

"The trouble with this area is there are not very many earthquakes," said Dick Schmidt, consortium director. "Therefore, it's very difficult to get a clear picture of the mechanism that's causing the earthquakes."

State geologist Jim Cobb said the 22-page study was not done to support efforts by the consortium or any other economic development group. The Greater Paducah Economic Development Council is working with the state on an incentive package for a 500-job uranium enrichment plant that uses gas centrifuge, a process highly susceptible to ground shaking. New study results presumably will be in that package, due to be sent to USEC Inc. this month.

"We didn't make the science come out to support what they were asking," he said. "We've been looking at this issue for 15 or 20 years, and our position has not changed."

Cobb said state geologists aren't alone because the U.S. Army Corps of Engineers is building the Olmsted Lock and Dam project with earthquake resistance consistent with "what we think."

State Rep. Charles Geveden of Wickliffe said the $500,000 request isn't unreasonable, even as the state faces a budgetary crisis.

"I certainly think it's worth it from an economic development standpoint. It pays for itself if one or two businesses locate in Kentucky," he said. "This could affect our regional industrial park. I'm sure the legislators from our area would support it and I would hope that whoever the next administration is would support it also."

The Kentucky survey hosted a November 2002 workshop in Lexington at which federal and state geologists sharply disagreed over the Purchase area risks, and the debate continues. Recent studies show there have been major quakes along the fault about every 500 years going back to the year 900, said Gary Patterson, a geologist and information services director at the Center for Earthquake Research and Information at the University of Memphis.

‘‘If you have a large earthquake in New Madrid, the whole region is going to be shaken silly, shaken very hard,’’ he said.

In 1811 and 1812, the New Madrid fault produced three of the strongest earthquakes in U.S. history, toppling chimneys as far away as Maysville and causing the Mississippi River to flow backward. Since 1996, there have been 196 earthquakes measuring from magnitude 2 to 6 along or near the fault. Every one-point increase in magnitude means a quake is 10 times stronger. A magnitude of 2.5 to 3 is generally the smallest that people can feel.

‘‘New Madrid really scares me,’’ said Jim Wilkinson, director of the Memphis-based Central United States Earthquake Consortium, an eight-state emergency preparedness group. ‘‘If New Madrid goes on the scale that we think it will, we are going to impede the entire country.’’

Some critics argue the study didn't have peer review and failed to disclose funding by the business-minded consortium. But Cobb said a similar paper by Kentucky geologists challenging USGS views will be published soon in a geologists' journal. Schmidt noted the study's executive summary says the work was done "with support from" the consortium.

Although the USGS recently lowered the probability of a major New Madrid earthquake, there is a 10 percent probability that a magnitude 7 to 8 earthquake could occur along the fault in the next 50 years, and a 25 percent to 40 percent probability of up to a magnitude 6 earthquake. Even tougher design standards went into state building codes in 2002, drawing protests from structural engineers.

‘‘Under that, we would not have been able to build a two-story brick veneer home in far-western Kentucky,’’ said Terry Slade, acting director of building code enforcement for the Kentucky Department of Housing, Buildings and Construction.

So Kentucky based its codes on a lower hazard that still called for more bracing and support, stronger foundations and virtually eliminating in the Purchase some backyard fixtures such as sunrooms, carports and decks. Paducah building inspectors, who have been working with the building codes for a year, say the extra expense is marginal — probably 1 percent or less for residential construction.

About 30 houses are built within the city each year. Paducah Building Inspector Joel Scarbrough estimates about 400 new homes out of about 7,000 in the city have been built under stronger earthquake codes since 1988.

The Associated Press contributed to this report.