REGIONAL REPORT : Little-Noticed Quake Law Now Producing Temblors : Development: The measure prohibits some kinds of construction within 50 feet of an active fault. In effect, it is a state-ordered zoning regulation.

Southern Californians have gotten used to living--and building--on the fault line.

Scores of faults, active and inactive, crisscross the region. Though their threat is deadly, that potential has not done much to limit growth and development--until recent years.

A little-known state law that forbids buildings “for human occupancy” in an active fault zone recently has shaken up Los Angeles, Orange and San Diego county agencies.

The law, formally entitled the “Alquist-Priolo Special Studies Zones Act,” prohibits within 50 feet of an active earthquake fault building or rebuilding any structure meant for human occupancy. State officials say the law will have an even bigger impact as improved technology pinpoints more faults. But even though the law has been on the books for 18 years, it seldom has drawn as much public attention as it has this year in Southern California:

* In Los Angeles County, the only permanent building at Los Angeles Southwest College is scheduled to be partially torn down. Last summer the 14-year-old structure was found to be straddling a fault, in violation of the Alquist-Priolo Act. Half the building must be razed for safety reasons, said college officials, who put the loss at about $35 million.

* In Orange County, the 4th District Court of Appeal last week ruled against the plaintiffs in a suit that charged that a new, $18-million waterfront condominium development stands at least partially in an earthquake fault zone. Much of the 18-month litigation about the condo project centered around the Alquist-Priolo Act.

* In San Diego County, state geological officials determined on Nov. 1 that two segments of an active earthquake fault extend about a mile through downtown San Diego and about five miles through the La Jolla area. As of that day, areas above or along the fault came under the restrictions of the Alquist-Priolo Act. No existing buildings face demolition. But new construction or reconstruction is now restricted.

Earlier this month, earthquake experts announced that the Santa Monica-Hollywood Fault may be more active than first believed. State Geologist Jim Davis, in an interview, said the fault so far is not listed by his office as “active” and thus is not subject to the Alquist-Priolo law.

But Davis said it is possible that the fault may one day be labeled as active. “As we get better and better mapping of faults at the surface, there is more and more zoning (restricting new construction),” Davis said.

The upshot is that land--already at a premium in urban Southern California--now faces another restriction. Alquist-Priolo, in effect, is a state-ordered zoning law.

Despite the land-use restriction near active faults, the construction industry has not suffered, according to Bob Norek, spokesman for the California Building Industry Assn. “There’s been enough land elsewhere that the industry has not found a problem with the law,” Norek said.

But state geologist Davis said that before the Alquist-Priolo Act, many builders had planned subdivisions on or near faults, plans which the law derailed. “There were plans for building subdivisions all over the San Andreas Fault,” Davis said.

Classifying a fault as active means it has had a surface earthquake within the past 11,000 years. Sometimes it takes many years of geological study, as with the new findings in San Diego, before enough evidence is available to classify a fault as active.

Statewide, 85 cities have active fault areas. San Diego is the latest to join that list.

Once the state has declared an active fault area, the adjacent land cannot be developed until a special geological study is conducted. Such a study, paid for by the developer, must prove there are no parallel active faults under the land. Such geological studies involve trenching and extracting material that might show earthquake disturbance within the past 11,000 years.

The Alquist-Priolo Act was enacted after the disastrous 1971 Sylmar earthquake.

“This is a law that ensures public safety and limits property damage and loss of lives,” said Chris Lindstrom, administrative assistant to Sen. Alfred Alquist (D-San Jose), who co-sponsored the legislation. “It doesn’t make sense to build over active faults.”

Hundreds of buildings already stood on or near faults when the act became law in 1973. Those buildings were exempted from the law. But no new or reconstructed buildings could be placed in the active fault areas unless a geological study proved the fault is not under the building.

While the law does not require tearing down any building that existed before the “active” finding, legal and ethical risks can make it unpalatable to use any building officially deemed earthquake unsafe. State officials do not keep track, but believe the college building is the first to be torn down under the act’s provisions.

Officials of the Los Angeles Community College District volunteered to tear down part of the offending building at Southwest College after finding out this year that it had been built over a fault.

“We have a responsibility for the safety of our students and staff,” said Kenneth S. Washington, a trustee of the college district.

The college building, used for administration and classrooms, is divided into four sections. Two of the four sections are within the fault danger zone and are to be torn down by spring.

“When the building was constructed, the technology was such that we didn’t know that a fault ran in that area,” said Stanley Viltz, an executive in the community college district.

Determination of active fault areas is sometimes imprecise. In the Orange County suit, for instance, there was disagreement among geological experts about where the fault line lay. The Santa Ana-based 4th District Court of Appeal, noting the discrepancy, said the lawsuit’s accusation against the project only amounted to a “shred of evidence representing one expert’s view.” The court added that “substantial evidence supports the . . . findings that the project complied with the Alquist-Priolo Act.”

The condo project, called the Huntington Harbour Bay Club, was finished last summer. Its 36 units cost an average $500,000. The waterfront site faces the well-to-do Huntington Harbour area of Huntington Beach.

“This is a very safe building,” said Jon Coultrup, the project’s managing partner. “It has been studied and restudied.” Coultrup said the project had been “slandered” in the suit, which had been brought by three Huntington Harbour residents. “The court has vindicated us,” Coultrup said, after the decision was announced last Thursday.

The three residents of Huntington Harbour who attacked the condo project in court initially opposed it on aesthetic grounds. But after hiring an attorney and studying the project, the residents found that an active line of the Newport-Inglewood fault traverses the harbor area. The residents’ suit contended that the condo project is within the 50-foot area banned for construction by the Alquist-Priolo Act.

The residents last week said they were not sure if they planned to appeal to the state Supreme Court. Their lawyer, Jonathan Lehrer-Graiwer, had argued before the Court of Appeal that the case “raises issues of statewide importance concerning the general public interest and the welfare and personal safety of residents.”

Lehrer-Graiwer had said that if the court agreed that the earthquake-safety law had been violated, the city of Huntington Beach might order part of the condo development torn down. The city was a co-defendant in the lawsuit.

In San Diego, the Alquist-Priolo Act has not caused construction problems so far, said Werner Landry, senior engineering geologist for San Diego’s Building Inspection Department. Landry said that although “quite a few” existing buildings are within the newly defined active-fault zones, none is in danger of being torn down because of the exemption for existing structures.

The main effect on San Diego, Landry said, will be restrictions on new buildings or renovation of existing ones. “We’ve always had seismic safety as part of our building code in this city, and so it (coming under the state law) does very little here in altering (building) requirements,” Landry said.