Business and Professions Code § 7835.1

All geophysical plans, specifications, reports, or documents shall be prepared by a professional geophysicist, licensed certified specialty geophysicist, professional geologist, licensed certified specialty geologist, or by a subordinate employee under his or her direction. In addition, they shall be signed by the professional geophysicist, licensed certified specialty geophysicist, professional geologist, or licensed certified specialty geologist, and stamped with his or her seal, both of which shall indicate his or her responsibility for them.