law requires the California State Geologist to establish regulatory zones (known as Earthquake Fault Zones) around the surface traces of active faults and to issue appropriate maps. ("Earthquake Fault Zones" were called "Special Studies Zones" prior to January 1, 1994.) The maps are distributed to all affected cities, counties, and state agencies for their use in planning and controlling new or renewed construction. Local agencies must regulate most development projects within the zones. Limitations Buildings built before 1972 may still lie on top of active faults, and those buildings can remain where they were originally built, unless they undergo a major remodel where more than 50% of the building changes. When that happens, they are treated the same as new construction (a geologic investigation must be undertaken and the hazard mitigated before a building permit can be issued). Projects include all land divisions and most structures for human occupancy. Single family wood-frame and steel-frame dwellings up to two stories not part of a development of four units or more are exempt. However, local agencies can be more restrictive than state law requires. While the act mandates that owners disclose the fact that their property lies within the Alquist-Priolo zone when they sell it, there are no legal requirements to disclose the fact to renters living on the property. Renters should investigate the location of active faults on their own before signing a lease or rental agreement. Legally, the act only applies to structures for human occupancy (houses, apartments, condominiums, etc.). However, the official geologic maps delineating the fault zones are used to help place a variety of structures on safe ground. For example, the Belmont Learning Center, a large school complex in Downtown Los Angeles was complicated by the discovery of a surface fault on the property in 2002. The Los Angeles Unified School District was required to remove a building that had been built directly atop the fault prior to its discovery. The act only addresses the hazard of surface fault rupture and does not address other earthquake hazards. The Seismic Hazards Mapping Act, passed in 1990, addresses non-surface fault rupture earthquake hazards, including liquefaction and seismically induced landslides. The act only applies to faults which are "sufficiently active" and "well defined"- for example the 1994 Northridge earthquake occurred on a blind thrust fault not zoned by the act because of a lack of surface evidence. References California Department