Geoethics in Hollywood: How Can We Put More Reality into Fault Hazard Zoning?

Abstract

The 15-km-long Hollywood fault extends through some of the most densely developed and expensive areas in southern California. Given that billions of dollars of real estate could be impacted by an earthquake occurring on the fault, and that tens of thousands of people live near it, the seismic hazard posed by the Hollywood fault is concerning. But how much so? The City of West Hollywood has required geological fault investigations and building avoidance of at least 15 meters from the fault’s active trace since the mid-1990s, resulting in numerous site investigations. Geologic studies in support of the Los Angeles Metro subway and subsequent research found as-yet-unconfirmedequivocal evidence of an early Holocene-age (~8 ka) displacement event, and estimated strain rates of 0.3-0.9 mm/yr. In 2014, and following a “not-in-my-backyard” press campaign against the Hollywood Millennium project, the California Geological Survey zoned the eastern Hollywood fault as Holocene-active under their fault zoning program, requiring geological investigations and building setbacks from Holocene-age faults. In the years since the fault was zoned by the City of West Hollywood and the California Geological Survey, millions of dollars have been invested in geological studies of the fault for building projects. All of these dollars have been reluctantly spent by the private sector, and all of this work has been eagerly done by consulting firms. The results? With only four exceptions, two in West Hollywood, and two in the City of Los Angeles, and all having opportunities for alternative interpretations, no Holocene-age fault displacements have been found. Instead, other studies have found definitive evidence that the fault has not ruptured in 10s to 100s of thousands of years. So what is the ethical alternative? Should we ignore the hazard posed by the fault? Are we geo-professionals too enamored of the financial gains such regulatory zoning provides that we are unwilling to suggest changes? Could we move past the “one size fits all” zoning that requires that single-family homes are held to the same standard as 40-story buildings? In the following sections we present several case studies along the Hollywood fault and provide our suggestions for a more progressive program of fault hazard management.