22.1 G: ALQUIST-PRIOLO FAULT HAZARD

22.1.1 Purpose. The purpose of these provisions is to implement the Alquist-Priolo Special Studies Zones Act (Public Resources Code, Section 2621 and following) in order to address potential hazards resulting from surface faulting or fault creep. (Former Section CZ#A314-51(A))

The Alquist-Priolo Fault Hazard

Regulations shall apply to lands which are designated “G” on the Zoning Maps, and which are within Special Studies Zones delineated on maps by the State Geologist. Regardless of the designation on the zoning maps, these regulations shall also apply to lands located within Special Study Zones delineated on the most recent maps that are officially adopted, revised or issued by the State Geologist. (Former Section CZ#A314-51(B))

The provisions of the Alquist-

Priolo Fault Hazard Regulations shall apply in addition to regulations imposed by the principal zone, development regulations, and other special area combining regulations. In the event of any conflict or inconsistency between these provisions and any other applicable provisions of the code, the most restrictive provisions shall apply in order to provide the greatest protection against fault hazards. (Former Section CZ#A314-51(C))

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

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22.1.4 Special Permit Required. Development may be approved in an area subject to the Alquist-Priolo Fault Hazard Regulations upon approval of a Special Permit, unless the development is exempt from the fault evaluation report pursuant to subsection 313-22.1.6. (Former Section CZ#A314-51(D))

22.1.5 Geologic Fault Evaluation Report Required. Application for a Special Permit for any of the following types of development shall be accompanied by a geologic fault evaluation report, prepared by a geologist registered in the State of California, which is directed to the problem of potential surface fault displacement through the project site, unless such project is exempt or the report is waived pursuant to subsection 313-22.1.6: (Former Section CZ#A314-51(E))

22.1.5.1 Parcel and Final Map Subdivisions, as defined by the Subdivision Map Act; (Former Section CZ#A314-51(E)(1))

22.1.5.2 Construction of any structure for human occupancy; (Former Section CZ#A314-51(E)(2))

22.1.5.3 Alterations or additions to structures for human occupancy the value of which exceeds fifty percent (50%) of the value of the structure; (Former Section CZ#A314-51(E)(3))

22.1.5.4 Any change in use or character of occupancy that results in the conversion of a building or structure from one not used for human occupancy to one that is so used. (Former Section CZ#A314-51(E)(4))

22.1.6 Exemption From Fault Evaluation Report Requirements. Notwithstanding the Geologic Fault Evaluation Report requirements, the following types of development are exempt from the requirement of a Geologic Fault Evaluation Report: (Former Section CZ#A314-51(F))

22.1.6.1 Construction, alteration, or additions of three (3) or fewer single family wood frame dwellings or manufactured homes, provided that they do not exceed two (2) stories; (Former Section CZ#A314-51(F)(1))

22.1.6.2 Construction, alteration, or addition of four (4) or more single family homes or manufactured homes, provided that they do not exceed two (2) stories and if the dwelling is located within a subdivision, as defined in the Subdivision Map Act, for which subdivision a Geologic Fault Evaluation Report has been approved or waived. (Former Section CZ#A314-51(F)(2))

22.1.6.3 Conversion of an existing apartment complex into condominiums. (Former Section CZ#A314-51(F)(3))

22.1.6.4 Any other development that may be exempt or excluded pursuant to the Alquist-Priolo Special Studies Zones Act, commencing with Public Resources Code Section 2621, and following. (Former Section CZ#A314-51(F)(4))

22.1.7 Content of Geologic Fault Evaluation Report. The required report shall be based on a geologic investigation designed to identify the location, recency, and nature of faulting that may have affected the project site in the past and may affect the project site in the future. The report may be combined with other geological or geotechnical reports. The report shall be prepared in accordance with the California Department of Mines and Geology (CDMG) Note #49 “Guidelines for Evaluating the Hazard of Surface Fault Rupture.” CDMG Notes #37, 43 and 44 shall be utilized as applicable when the fault evaluation report required herein is combined with other geological or geotechnical reports. (Former Section CZ#A314-51(G))

The Humboldt County Code is current through Ordinance 2784, passed March 10, 2026.

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22.1.8 Waiver of Required Report. Waiver from the geologic fault evaluation report required herein may be applied for pursuant to the procedure outlined in Appendix D, “Waiver Procedure for the Alquist-Priolo Act,” contained in Special Publication 42 “Fault-Rupture Hazard Zones in California,” California Division of Mines and Geology, 3/80, or any subsequent publication which is prepared for the same or similar purpose. Granting of such a waiver is subject to the approval of the State Geologist. (Former Section CZ#A314-51(H))

22.1.9 Required Findings. The Hearing Officer may approve a Special Permit for development located within an Alquist-Priolo Special Studies Zone if all of the applicable Public Safety Impact Findings of Chapter 2, Procedures, Supplemental Findings, are made.

313-23 through 313-26 (Sections Reserved for Future Use)

313-27 “L” Combining Zone Designations