Chapter 15.20 — GEOLOGIC REPORTS

The purpose of this Chapter is to mitigate the hazard due to fault rupture by limiting the placement of structures for human occupancy across the trace of active faults.

(Prior code § 2-8.01)

Unless specifically exempted in Section 15.20.040, this Chapter applies to any new structures, major additions or alterations to any existing structures, replacements of existing structures and subdivisions located wholly or partly within the Special Studies Zone.

(Prior code § 2-8.02)

For the purposes of this Chapter certain words and phrases are defined, unless it shall be apparent from their context that a different meaning is intended:

"Active fault" means a fault where surface displacement has occurred within Holocene time.

"Fault" means a fracture or zone of closely associated fractures along which rocks on one side have been displaced with respect to those on the other side. Most faults are the result of repeated displacement which may have taken place suddenly or by slow creep or by a combination thereof.

"Fault trace" means the line formed by the intersection of a fault and the earth's surface.

"Geologic event" means the occurrence of any movement of the earth surface relating to earthquake faults. The determination of such ground movement shall be based on field observation, established geologic data or actual evidence of earth surface movement.

"Geologic Report" means a report prepared by a geologist for a particular site which is directed toward the problem of potential surface fault displacement and the damage which would result therefrom.

"Geologist" means a geologist registered as such by the Department of Professional and Vocational Standards of the state of California.

"Habitable space" means space in a structure for living, sleeping, eating or cooking. For the purpose of this Chapter, habitable space shall include areas designed and built as occupiable space such as living rooms, family rooms, dining rooms, bedrooms, kitchens, bathrooms, hallways and other similar areas. Unfinished underfloor spaces, crawl spaces, garage, and storage, utility or closet spaces are not considered habitable space.

"Major addition or alteration" means addition or alteration, as defined in Oakland Building Code, to an existing structure which exceeds fifty percent of the value of the structure within any twelve-month period.

"Replacement" means the reconstruction, renewal, restoration, or upgrade to current building code of any part of an existing building damaged or destroyed by an involuntary event. For the purpose of this Chapter, replacement work shall be limited to the pre-damaged size, location, occupancy and use of the existing building.

"Special Studies Zones" means those areas within the boundaries of the Special Studies Zone as adopted by the California State Mining and Geology Board pursuant to the Alquist-Priolo Geologic Hazard Zones Act.

"Special Studies Zone Map" means that certain map delineating the Special Studies Zone on file January 1, 1982 in the Office of Public Works, and all subsequent revisions thereof adopted by resolution of the Council.

"Story" means that portion of a building included between the floor surface of any floor and the floor surface of the floor next above, except that the topmost story shall be that portion between the floor surface of the topmost floor and the ceiling or roof above. For the purpose of this Chapter, any floor level which qualifies as a mezzanine or having less than three hundred (300) square feet of floor area of habitable space shall not be considered a story.

loor surface of any floor and the floor surface of the floor next above, except that the topmost story shall be that portion between the floor surface of the topmost floor and the ceiling or roof above. For the purpose of this Chapter, any floor level which qualifies as a mezzanine or having less than three hundred (300) square feet of floor area of habitable space shall not be considered a story.

"Structure for human occupancy" means any building or structure that is regularly, habitually or primarily occupied by humans, except for detached buildings or structures classed as Group J Occupancies in the Oakland Building Code.

"Technically qualified personnel" are those persons deemed qualified by the California State Mining and Geology Board to evaluate geologic and engineering reports.

(Prior code § 2-8.03)

This chapter shall apply to the following projects:

A.

New Structure. Any new structure for human occupancy with the exception of:

Single-family wood frame dwelling located within a real estate development for which a geologic report has been approved;

A single-family wood frame dwelling not exceeding two stories when such dwelling is not part of a development of four or more dwellings and is not located within one hundred (100) feet of a potentially active fault as depicted on the Special Studies Zone Map or of a field located active fault.

B.

Major Addition or Alteration. Any major addition or alteration to an existing structure for human occupancy with the exception of:

Single-family wood frame dwelling located within a real estate development for which a geologic report has been approved;

A single-family wood frame dwelling not exceeding two stories.

C.

Replacement. Any replacement of an existing structure for human occupancy if the damage is caused or related to geologic event with the exception of:

Single-family dwelling;

Replacement to any existing structure which does not exceed fifty (50) percent of the value of the structure within any twelve (12) month period.

D.

Subdivision. Any subdivision which requires a tentative subdivision map pursuant to the provisions of this code for a proposed subdivision except for a subdivision which consists solely of the division of an existing structure for human occupancy. Any land determined to be unbuildable due to the location of a fault trace shall be so designated on the tentative map.

(Prior code § 2-8.04)

City requires four copies of geologic report defining and delineating any fault hazard prior to the approval of any applicable project as defined in Section 15.20.040, and:

A.

If no fault hazard is identified, no additional requirement in the chapter shall be applied.

B.

If fault hazards are determined, no structures for human occupancy shall be permitted to be placed:

Across an active fault trace;

Within fifty (50) feet of any active fault trace unless the geologic investigation can demonstrate that the site is not underlain by active branches of the fault. In such case the structure can be placed closer to the fault as recommended by the geologist and approved by the city but not across the fault.

(Prior code § 2-8.05)

Each geologic report shall be accompanied by a map of the site being investigated. The map shall conform to the requirements set forth in this subsection.

A.

The following information developed for a survey of the site by a civil engineer registered as such by the state of California, or a land surveyor licensed by the state of California, shall appear on a plat of a survey of the site:

The exterior boundary lines of the site and their courses;

The record distance along the street property line from a side line of the property to the nearest intersecting street;

Contour lines at not more than five-foot intervals;

The location of the proposed improvements and the grades at which they are to be constructed, if applicable;

The location of existing buildings or other pertinent structures on the property, if applicable;

The location of the existing curbs, sidewalks, public sewers, public conduits, waterways and culverts on, or affecting, the property and any existing easements required in connection therewith;

The location of the proposed house sewer connecting the proposed improvements to the main sewer or septic tank with the flow line elevation shown at the main sewer connection, if applicable.

B.

The geologist preparing the geologic report shall cause the following information to be placed on the map:

The location of any potentially active or active fault traces on the site;

The location of test holes, borings or trenches;

A typical geologic cross-section of the site;

Any other items the geologist may deem necessary in rendering an opinion in the geologic report.

C.

The following statement, together with the signature and registration number of the geologist preparing the geologic report, shall be placed on the map:

The locations and limitations of the geologic features shown on this map are accurate representations of said features as they exist on the ground, were placed on this map by me or under my supervision, and are accurate to the best of my knowledge.

(Signed) _____

Number _____

(Prior code § 2-8.06)

The geologic report of the site being investigated shall include an analysis of the geologic conditions, together with a statement by the geologist describing potential dangers and whether or not it is feasible to build on the site. Recommended restrictions on proposed construction on the site shall be included, or a statement by the geologist that the site is in all probability free from danger related to earthquake fault traces and that no further studies are necessary.

The signature and registration number of the geologist and the date shall follow the final paragraph of the report.

(Prior code § 2-8.07)

The applicant or subdivider shall bear the entire cost of preparation of the geologic report.

(Prior code § 2-8.08)

Geologic reports submitted pursuant to this Chapter shall be evaluated by technically qualified personnel employed or retained by the city. Personnel reviewing the geologic report shall approve the report, reject it, or withhold approval pending the submission by the applicant or subdivider of further geologic and engineering studies to more adequately define active fault traces.

No building permit or subdivision map requiring the submission of a geologic report shall be granted or approved without approval of the geologic report by technically qualified personnel employed or retained by the city.

(Prior code § 2-8.09)

A.

The geologic report otherwise required by Section 15.20.020 may be waived with the approval of the State Geologist where, in the judgement of technically qualified personnel employed or retained by the city, sufficient information regarding the site is available and no undue geologic hazard exists.

B.

An applicant or subdivider seeking a waiver pursuant to this Section shall furnish such information which technically qualified personnel employed or retained by the city shall deem necessary in passing on the waiver application.

(Prior code § 2-8.10)

After a geologic report has been approved or waived pursuant to this Chapter, no subsequent geologic report shall be required for the same site; provided, however, the Director of Public Works may call for the preparation of a new geologic report or amendments to an existing report where:

A.

He or she has reason to believe that geologic conditions have changed.

B.

Improvements in the state of the art of geology have rendered existing reports inaccurate or incomplete.

(Prior code § 2-8.12)