Saturday, April 17, 1999
County Blasted on Palace Quake Safety Expansion will proceed despite consultants' conflicting reports on whether a fault lurks under site
BY LEE SIEGEL THE SALT LAKE TRIBUNE
Salt Lake County is under fire for deciding to build a $47.5 million expansion of the Salt Palace Convention Center even though one of two teams of consultants says the site sits atop an active earthquake fault. The other team says there is no fault.
"The answer is to resolve the conflict instead of setting a poor precedent and going ahead with a structure on a questionable site," said University of Utah geography Professor Don Currey.
Proceeding with construction while consultants disagree "is not satisfactory," geology consultant Bruce Kaliser said Friday. "The technical people need to resolve this," said Kaliser, a former Utah Geological Survey geologist.
"We have resolved it," replied County Commissioner Brent Overson, who is convinced no fault is under the site. "Somebody has to make a decision and we are making it."
The county opened nine construction bids Thursday, but a winner will not be picked and construction cannot begin until Salt Lake City issues a building permit. A permit decision is likely in early May after the city has the conflicting reports reviewed by a California consultant, said Roger Evans, the city's building director.
City and county ordinances outlaw building atop a fault line, where an underground fault intersects the surface. That is because a major quake can break the ground on the fault line, ripping apart overlying buildings.
Ken Ament, who manages Salt Palace construction work, said that after spending $200,000 to $250,000 on studies by two groups of consultants, the county rejected the opinion of Bountiful geologist David Simon of Simon-Bymaster Inc. His report concluded "the preponderance of evidence" indicates an active quake fault runs beneath the site, and likely is the southern end of the Warm Springs branch of the Wasatch fault.
The other report was written by Kleinfelder Inc. consultants and Les Youd, civil engineering chairman at Brigham Young University and ex-chairman of the Utah Seismic Safety Commission. Kleinfelder and Youd believe fractures and other signs of strong shaking at the Salt Palace site were caused when waterlogged ground there liquefied like quicksand, then spread apart during a prehistoric quake caused by a fault elsewhere.
Because the water table now is deeper, Kleinfelder and Youd believe liquefaction in a future big quake would make the ground move horizontally or vertically by no more than three inches. The county accepted their recommendation to strengthen the Salt Palace expansion's foundation.
Asked why the county is rejecting Simon's conclusions, Overson said: "Simon has no credibility in my book" because "he changed his mind" several times on whether a fault existed at the site.
"We changed our opinion as more data became available and time was given to thoroughly and correctly interpret it," Simon replied.
Simon was not alone in changing his opinion. Youd said some Kleinfelder geologists also argued the site had an active fault, but ultimately concluded otherwise.
Salt Lake County hired Maxim Technologies to study the site's geology, but Maxim lacked a Utah fault expert, so the work was given to Simon. He found small faults and signs of liquefaction in City Creek stream sediments beneath the site in December, and said it appeared an active quake fault extended beneath the Salt Palace and the expansion site.
After discussions among consultants, Simon said Feb. 2 he agreed with Kleinfelder that the fractured earth likely was not a quake fault. But in his final report, Simon concluded the site's small faults are linked at greater depths to form a single quake fault.
Kleinfelder used a device called a cone penetrometer to bore into the ground to detect different sediment layers under the site. The tests found deeper Lake Bonneville sediments are unbroken across most of the Salt Palace expansion site. That indicates the shallow faults were caused solely by liquefaction. A major quake fault would have broken the deeper sediments, not just the shallower deposits.
Simon's report, however, said not enough measurements were made to detect the quake fault he believes exists under the site. Even though Youd doubts any fault is present, he said Simon makes "a legitimate argument. . . . It clearly needs some more study."
Overson and Ament said the Salt Palace site has been studied more exhaustively than any downtown property.
The tests found an area on the southeast corner of the Salt Palace site -- east of where the new building will be located -- where Lake Bonneville sediments were nine feet lower than sediments on either side.
Youd said if that underground trough was a major fault, Bonneville sediments east of the Salt Palace site should be at a shallower depth than those beneath the site. That's because during big quakes on "normal" faults like the Wasatch fault, ground on one side of the fault rises above ground on the other side. No such uplift was found, Youd said.
Simon believes if the fault is the southern end of the Warm Springs fault, a big quake could make the ground spread apart without uplift.
Simon's report also noted the county's 1989 geologic hazards map shows the Warm Springs fault might run along the east side of the Salt Palace property.
Simon "is on pretty solid ground," Currey said. "It is logical a fault is present."
Craig Nelson, Salt Lake County's former geologist, said more study of the site is needed but the county "stopped when they got the answer they liked."
"Bull," Ament said. The county "got a second and third opinion [from Kleinfelder and Youd] and they agreed it was buildable."
However, minutes of a Jan. 14 meeting of the county's Salt Palace expansion team said: "Ken Ament stated that he expected a by-the-book analysis with conservative recommendations from Maxim [and Simon]. He expected a more liberal interpretation from Kleinfelder and hopefully a more palatable series of recommendations and solutions."
Page Modified April 17, 1999