When the Big One hits and the earth starts to rumble, you probably don't want to find yourself in the fitting room of Nordstrom's or Macy's in the Stanford Shopping Center.

If you're lucky, you won't be watching a movie at Palo Alto Square, dining at MacArthur Park or hanging out at the Palantir cafeteria at 542 High St.

These five structures are among 89 that the city deemed in 1986 to be seismically vulnerable. They are also among 22 whose owners to this day have done nothing to change that fact, according to a recent city assessment. The list of buildings that have not been upgraded also includes the Cardinal Hotel at 231 Hamilton Ave. and the Palo Alto Woman's Club at 475 Homer St.

The number of buildings in Palo Alto deemed vulnerable is generally assumed to be much higher than the 22 identified in the recent status report, though an exact number has been hard to peg. Ken Dueker, director of the city's Office of Emergency Services, told the City Council last year that the city has 22 unreinforced masonry buildings, which by definition are not braced by reinforcing beams. There are also about 124 "soft story" structures -- multistory buildings such as garages or large retail stores in which one or more floors are dominated by large open spaces with no shear walls.

Both designs are considered seismically shaky. In his update to the council in September, Dueker observed that soft-story buildings "tend to collapse catastrophically and it looks like there never was a garage under there to begin with."

But what should the city do about these buildings? That's the question that the council is preparing to tackle in the coming months, as it moves along with its first major assessment of seismically vulnerable structures since the late 1980s. On Aug. 18, the City Council is expected to approve a $129,432 contract with the firm Rutherford + Chekene to come up with a new inventory of the city's potentially hazardous structures. The council will then consider ways to get the building owners to make the needed fixes.

The new assessment is expected to differ drastically from the one conducted in 1986. At that time, the survey was limited to three categories of buildings: ones constructed of unreinforced masonry, ones built before 1935 and containing 100 or more occupants, and ones that were built before Aug. 1, 1976 and contain 300 or more occupants. Under a law the council adopted in 1986, owners of the buildings on the list had to provide the city with an engineering analysis. Retrofitting, however, was optional, and not every building owner took that option. Of the 89 buildings in the three categories, 39 have been strengthened, 21 have been demolished, four were proposed for demolition and one had its unreinforced wall removed.

The new survey will be broader in scope and will include buildings with tilt-up construction, non-ductile concrete and steel-moment-resisting frame -- typologies that were not reviewed in 1986 but that are now recognized as vulnerable. It will focus on multifamily, commercial and industrial buildings of the city. And once it's in place, it will set the stage for what many expect to be a difficult community conversation as the council considers ways to ensure compliance.

The topic of earthquake safety returned to the city's spotlight last year, when staff completed what is known as a Threat and Hazard Identification and Risk Assessment (THIRA) report, which summarizes some of the top threats facing Palo Alto. Perhaps not surprisingly, given Palo Alto's proximity to both the San Andreas and Hayward faults, earthquakes ranked at the top of the "natural disaster category."

The report notes that past land-use decisions in Palo Alto "have not always taken hazards into consideration."

"Moreover, older buildings and infrastructure reflect the construction and engineering standards of their era, which in most cases fall short of current standards for seismic safety," the threat assessment states. "As a result, a portion of the city, including 130 soft-story structures, would be at some risk in the event of a major earthquake."

While the greatest hazards are associated with fault rupture and ground shaking, the report notes, other potential threats include liquefaction east of U.S. Highway 101; landslides in the foothills; and seismically induced flooding because of possible dam failure at Felt Lake and Searsville Lake, as well as potential levee failure near the San Francisco Bay.

In response to this threat report, the council directed staff and its Policy and Services Committee to consider ways to identify vulnerable structures, review best practices from other communities and consider current or pending state legislation relating to soft-story buildings and other seismically deficient structures. In December, the committee unanimously endorsed staff's proposal to commission a new assessment that would include the additional typologies of potentially vulnerable buildings.

Greg Schmid and Greg Scharff, who served on the committee last year, both expressed enthusiasm for the new effort to make the community seismically safer.

Scharff called the effort to upgrade safety standards a "life safety" issue and recalled his experience during the 6.6-magnitude quake that hit Los Angeles in February 1971.

"I remember my bed just flying across the room," Scharff said during the committee's Dec. 9 discussion. "That's how I woke up -- the bed was flying across the room.

"It's one thing for the bed to fly; it's another for the building to come pancaking down like that," he added, slapping his hand down.

Though the effort to update the inventory is still in the early phase, the council faces the likely contentious consideration of whether retrofits should be voluntary or mandatory.

"There will be some difficult decision as the council and the committee of the council and the community evaluate the need to reduce risk to property and life against the high cost of retrofitting buildings," Assistant Planning Director Jonathan Lait told the committee during the December meeting. "It can be significant in many instances."

City Manager James Keene, who oversaw Berkeley's seismic upgrades of its public building during his stint as the city manager there, concurred with Lait's assessment.

"It's potentially a big deal," Keene said. "We have to be clear about that."

Scharff said he would favor measures that would make compliance mandatory rather than optional, despite the high cost of retrofitting some of the buildings on the list. But he said he believes the city should focus on large residential and commercial structures over smaller retail buildings, noting that businesses like Mills Florist at 233 University Ave. and SOS Grocery at 949 Emerson St. could struggle to cover the cost of a major retrofit.