The California Geological Survey on Wednesday issued the most detailed fault maps to date of two earthquake zones, including the much debated Hollywood Fault that has held up the Millennium Hollywood skyscraper project.
The second map was for the Sierra Madre Fault in the San Gabriel Valley.
The maps are considered preliminary and will go under public review for at least 90 days before they are finalized.
Identifying earthquake zones is important because once established, they place restrictions on development within the zones.
Mapping earthquake zones was a component of the 1972 Alquist-Priolo Act. It requires cities to restrict development within the zones.
Developers looking to build within a mapped earthquake zone must dig test trenches to make sure they are not erecting structures directly on top of a fault line. Such buildings can be ripped in two in a major earthquake.
If the trenches uncover evidence of a fault line, developers must move construction at least 50 feet away from the fault.
The preliminary maps will not carry the force of law to affect development decisions, said Don Drysdale with the California Department of Conversation.
California State Geologist John Parrish was among the state officials who unveiled the preliminary maps Wednesday.
He said even though the maps won't require city officials and developers to take action immediately, he said he hopes people pay attention.
"Even though these are not enforced yet, a prudent decision would be, I know there's a hazard there I should take precautions and study and try to define that hazard as best I can," he said.
Parrish estimated that the preliminary maps are accurate to within about 50 feet, and he doesn't expect major changes before they are finalized this summer.
"We are very thorough, usually there are very few, if any, changes that are made," he said.
The Hollywood Fault runs west to east from West Hollywood to Atwater Village, weaving through busy retail and residential areas of Los Angeles.
At a press event after the Hollywood map was released, Robert Silverstein, the lawyer representing opponents of the Millennium Hollywood project, said the map reinforces his group's claim that the city officials erred when they approved the project without requiring seismic testing.
"This is an incredible indictment of LA city hall," Silverstein said.
He said he will amend his current lawsuit against the project to include information from the new state map.
"I expect that that will be a further nail in the coffin of the Millennium Hollywood project," he said.
The communications firm for Millennium Hollywood issued a statement Wednesday saying it will conduct additional "subsurface investigation" before any building permits are issued.
"Millennium Hollywood remains committed to building a safe project to the highest earthquake resiliency standards," the statement said.
In a statement, Luke Zamperini, a chief inspector for the Los Angles Department of Building and Safety said the city isn't waiting for the final Hollywood fault map, due in July. It plans to use the preliminary map to inform future development decisions in the meantime.
But he wrote that previous approved projects, like Millennium Hollywood, that have not yet begun construction "will be evaluated on a case by case basis to determine if a fault rupture study will be required."