In order to make appropriate evaluations of geologic reports, the reviewer should be an experienced geologist familiar with the investigative methods and techniques employed by the profession. In California, the reviewer must be licensed by the State Board of Registration for Geologists and Geophysicists in order to practice. Local agencies may have additional requirements. The most critical item in a site investigation is the geologic report. The investigation of sites for the possible hazard of surface fault rupture is a difficult geologic task.
Many active faults are complex, consisting of multiple breaks.
Most surface faulting is confined to a relatively narrow zone a few feet to a few yards wide, making building set-back the most appropriate mitigation method. The evaluation of a given site with regard to the potential hazard of surface fault rupture is based extensively on the concepts of recency and recurrence of faulting along existing faults. Each month the Division of Mines and Geology gets dozens of requests for color copies of the seismic hazard zone maps. Division of Mines and Geology staff are testing production of copies of the color maps and we hope to have them available later this year. April is California Earthquake Preparedness Month.