GEOTECHNICAL ENGINEERING GROUP (GEO) · city of los angeles . department of public works . bureau...

CITY OF LOS ANGELES DEPARTMENT OF PUBLIC WORKS

BUREAU OF ENGINEERING

GEOTECHNICAL ENGINEERING GROUP (GEO)

GEOTECHNICAL REAL ESTATE DISCLOSURE REPORT FOR CITY OWNED LOT 15206 EARLHAM STREET, PACIFIC PALISADES, CA 90272 W.O. E170213F GEO FILE # 05-159 MAY 15, 2014

TABLE OF CONTENTS GEOTECHNICAL REAL ESTATE DISCLOSURE REPORT

CITY PROPERTY 15206 EARLHAM STREET

1.0 INTRODUCTION .................................................................................................................. 1 2.0 PURPOSE ............................................................................................................................. 1 3.0 SCOPE OF REPORT .......................................................................................................... 1 4.0 GENERAL SITE LOCATION AND DESCRIPTION OF PROPERTIES ..................... 2 5.0 HISTORY AND BACKGROUND ....................................................................................... 2

5.1 PHYSIOGRAPHY ................................................................................................................. 2 5.2 POTRERO CANYON HISTORY AND EXPLORATION ACTIVITY ............................................. 3 5.3 REVIEW OF RELEVANT RAP AND PUBLIC WORKS RECORDS RELATING TO POTRERO CANYON GRADING ...................................................................................................................... 5 5.4 2010 URS REPORT DESCRIPTION AND EXPLORATION IN THE AREA OF 15206 EARLHAM STREET ....................................................................................................................................... 9 5.5 HISTORY OF DEVELOPMENT AND GEOTECHNICAL EXPLORATION OF 15206 EARLHAM STREET AND ADJACENT PROPERTIES ...................................................................................... 10

6.0 GEOLOGY .......................................................................................................................... 13 6.1 GEOLOGIC SETTING ........................................................................................................ 13 6.2 EARTH UNITS ................................................................................................................... 13 6.3 GEOLOGIC STRUCTURE ................................................................................................... 14 6.4 GROUNDWATER ............................................................................................................... 14 6.5 SEISMIC HAZARDS ........................................................................................................... 15

7.0 PROPERTY WALK-THROUGH ...................................................................................... 16 7.1 15206 EARLHAM STREET ............................................................................................... 16

8.0 REAL ESTATE DISCLOSURES ..................................................................................... 18 9.0 REQUIREMENTS FOR GEOTECHNICAL INVESTIGATIONS WITHIN CITY OWNED PROPERTIES ............................................................................................................ 19 10.0 LIMITATIONS ..................................................................................................................... 20 11.0 SELECTED REFERENCES ............................................................................................. 22

Appendix A: Figures 1-27

Appendix B: 15206 Earlham Street Property Photos 1-58

Geotechnical Real Estate Disclosure – 15206 Earlham St May 15, 2014 GEO File No. 05-159 W.O. E170213F Page 1 of 24

1.0 INTRODUCTION

The City of Los Angeles provides this report of geotechnical real estate disclosure in response to a request from the Department of General Services Asset Management Division. This geotechnical disclosure report is based in part on review of readily available geotechnical records and reported data from past geologic subsurface exploration and geologic mapping by others in the immediate vicinity of the City owned property covered by this report, 15206 Earlham Street, Los Angeles, CA 90272 also known as lot 2, hereafter referred to as the ‘subject property’ or specifically as needed. 2.0 PURPOSE

The purpose of this report is to provide geotechnical information compiled for the subject property and to make the buyer aware of the overall geotechnical condition of the property. This disclosure is not a guarantee of any kind nor does it take the place of a thorough geotechnical investigation or warranty the buyer may wish to obtain. This disclosure report is a summary of readily available geotechnical information concerning the subject properties for the purpose of disclosing such information for future real estate transactions. This report is not a substitute for engineer reports, soils and geology reports, environmental impact reports, special studies that may be required by the Los Angeles Department of Building and Safety, the California State Coastal Commission, or any other regulatory agency prior to any improvements on the subject lot.

3.0 SCOPE OF REPORT

This report is based in part on document review, visual site observation, review of readily available documented subsurface investigations and past grading work on or adjacent to the property. Tasks completed in the preparation of this report included:

• Review of readily available aerial photographs, past and current; • Review of published geologic maps and reports of the site area contained within

Geotechnical Engineering Division (GEO) files; • Review of readily available relevant documents on file at the City of Los Angeles

Department of Recreation and Parks (RAP); • Review of geotechnical reports obtained from the City of Los Angeles Department of

Building and Safety (LADBS) files; • Site observation and reconnaissance of adjacent areas. This disclosure is based on what the City of Los Angeles is aware of and data available to the City at the time of the preparation of this report.


4.0 GENERAL SITE LOCATION AND DESCRIPTION OF PROPERTIES

The subject property covered by this report is located adjacent to Potrero Canyon (see Figure 1, lot numbered 2 adjacent to and part of the landslide designated as Slide #5) on the southern side of Earlham Street directly west of where Earlham Street transitions into De Pauw Street to the east in the Pacific Palisades community of Los Angeles. The back of the lot faces south into a tributary canyon of the main Potrero Canyon. The lot dimensions for the property are approximately 50 feet wide at Earlham Street and 87 feet wide at the rear of the lot, and 150 feet deep with a total area of approximately 10,340 square feet. The general topographic trend of the property is downslope towards the southwest, 24 feet below street grade at the rear of the lot, continuing off property into the tributary canyon in a series of steps downward to the floor/centerline of the tributary ‘channel’ more than 75 feet below street grade of Earlham Street. The ‘overall’ slope to the centerline of the tributary ‘channel’ from Earlham Street in the area of the subject property is approximately 5:1 (horizontal:vertical). The northern property line of the properties is setback approximately 20 feet from the street. The subject property contains a residential structure and a detached carport (which appears to encroach into the public right of way.) The existing conditions from an aerial view (as of 2010) of the lot along the relevant section of Earlham Street with addresses, lot numbers, and topography are shown in Figure 2. As shown in Figure 2, the residential structure of 15202 Earlham Street appears to encroach onto the property of 15206 Earlham Street; further potential encroachment issues are discussed further in the ‘property walkthrough’ in Section 7 of this report. City records show that portions or all of the property is in the following ‘Special’ zoned areas: hillside ordinance, hillside grading, very high fire hazard severity, fire brush clearance, landslide, and coastal commission zones. More detailed descriptions of the individual City owned property are included in Section 7.0 of this report.

5.0 HISTORY AND BACKGROUND

5.1 Physiography

The property rests on a relatively flat marine and non-marine terrace that was dissected by fluvial processes that formed Potrero Canyon downslope at the rear of the properties. Potrero Canyon is a southwest draining canyon which trends across the Pacific Palisades area immediately north of Pacific Coast Highway (PCH). In this area, PCH trends northwest. Immediately south of the highway is Will Rogers State Beach. The relatively flat marine terraces bounded by the steep cliffs or palisades above the canyon have been developed as residential areas. Backyards of the residential areas are open to the relatively steep canyon slopes or, in the case of much of Potrero Canyon, graded 2:1 slopes. Unlike the neighborhoods above, there are no housing developments or public streets in the bottom of Potrero Canyon. The canyon walls of Potrero Canyon became over steepened in the past due to undercutting by the pre-existing seasonally flowing stream at the canyon bottom, which led to surficial failures and landslides in the canyon in recent geologic history. The major landslides within the canyon were numbered as part of a canyon wide geotechnical exploration in 1986. For the purposes of this report the numbering system has been retained and included as


Figure 1 for reference and hereafter all landslides will be referred to as ‘Slide #1-9’ whenever applicable. 5.2 Potrero Canyon History and Exploration Activity

In 1922 development of the eastern Pacific Palisades started with installation of water lines and construction of roads followed by home building (Moran et al, 1959). Road grading on the mesas above Potrero canyon also began in the early 1920’s (Buckley, 1987). Based on a review of available airphotos, the grading of the tract surrounding and including the properties was complete by 1929. The airphoto from 1929, Figure 3, shows approximately 10 houses on the west mesa above the rim of Potrero Canyon. The 1929 canyon itself appears in its natural state. At the time, the canyon bottom was approximately 110 feet below the level of Earlham Street. No records of movement within the canyon exist prior to 1933, but it has been postulated that the incision of the active stream in the canyon bottom would have been undercutting and began removing lateral support from the canyon walls much earlier (Moran et al, 1959). In 1939, sanitary sewers were installed on the bluff (Moran et al, 1959). Moran et al, 1959, mentions early slope stability problems in Potrero Canyon, citing that filling of the canyon had been considered by the City of Los Angeles and private interests in order to stabilize slopes and provide a recreation area. At that time, the City was interested in possibly using the canyon for a disposal area for solid refuse, street sweepings and excess soil. The west rim of Potrero Canyon became densely developed in the early 1950’s and with development came increased landslide activity. Throughout the 1950’s there were reports of movement of landslides over the extent of Potrero Canyon, including Slides #1, 2, 3, 4, 5, 7, and 8 (refer to Figure 1); Slide #5 was active since 1958 and broke utility lines, which were subsequently repaired, beneath Earlham Street in 1959 at the head of the slide (Moran et al, 1959).

In 1959 an extensive geotechnical exploration of a wide area of Pacific Palisades was conducted by Moran, et al that studied the landslides of the area (Moran et al, 1959). The report studied the slides within Potrero Canyon with multiple borings, piezometers and slope inclinometers. Slides studied during this period were occurring primarily on the west side of the canyon likely due to a generally more out of slope bedding condition when compared to the east side. The study determined that the slides were caused by the groundwater flow regime, weak earth materials, and over-steepening of the canyon walls by stream erosion. It is generally thought that the development of the mesas raised the general groundwater levels of the area. It was recommended that a central storm drain installed, the canyon be filled with 40-70 feet of fill, and hydrauger drains installed above the fill. The slide material that would have remained above the fill was recommended to be allowed to erode to point of self-stabilization.


As shown in Figure 4, Slide #5 was mapped, explored, and studied by Moran, et al, 1959. As part of the study a boring, designated 108, was advanced in the head area of the slide mass to approximately 73 feet below the then existing ground surface (BGS) and then converted to a slope inclinometer. Boring 108 encountered fill to a depth of 5 feet BGS, landslide material to 57 feet BGS, and Modelo Formation bedrock to the boring termination. Slide #5 was mapped by Moran, et al extending from near the canyon bottom at the toe of the slide, to the headscarp area on the northern side of Earlham Street. Groundwater seeps were noted at elevation 230 msl in the area of Slide #5. Sudden landslide movement in 1959 was captured in the inclinometer data which showed a 3 ft rise in groundwater pressure. Inclinometer data also showed that landslide movement was occurring on a circular arc through alluvium and the underlying Modelo Formation. (Moran, et al, 1959) Geotechnical testing of the Modelo Formation bedrock showed an intermediate strength with a cohesion of 0.74 ksf and tan phi of 0.35. Based on this data, as shown in Figure 5, (note: Slide #5 is referred to as ‘Location 5’) stability analysis conducted showed that sixty feet of fill in the canyon at Slide #5 would provide a factor of safety approaching 2.0. Elsewhere in the report, it was noted that 40 to 70 ft. of canyon fill would provide a factor of safety of 1.5 against failures occurring from the canyon bottom to the mesa top.

The canyon was purchased by the City of Los Angeles in the 1960’s with the intention to utilize the canyon as a southern extension of the existing Palisades Park (Buckley, 1987). The City then initiated several studies to determine best course of action to create useable parkland and improve the stability of the slopes within the canyon.

The files of Public Works contain reports for remedial repair of the roadway, including a bulkhead constructed to support the street, and utility repairs adjacent to the subject property regarding Slide #5. Recommendations for reconstruction of Earlham Street and installation of dewatering wells are contained in the reports "15211 Earlham Street-Preliminary Report on The Landslide Within the Roadway Adjacent Thereto", Job #163-185 dated November 12, 1969 and "Supplemental Report, 15211 Earlham Street Dewatering Wells," dated June 15, 1971. The reports from 1969 and 1971 were not directly reviewed in the preparation of this disclosure report. Documents regarding the construction of the bulkhead or utility line repairs were not located or reviewed as part of this report, however plans for the bulkhead and the area storm drain lines were located and reviewed and can be made available upon request. Cracking in Earlham Street observed after the bulkhead was constructed was seen to be potentially caused by settlement of debris and/or plastic flow around the bulkhead, or a yielding of the piles (KBA, 1986.)

In 1979, several pre-existing ancient landslides became active and threatened upslope residences (KBA, 1990); among them was Slide 3 which occurred southeast of the subject properties. Slides 2 and 3 reactivated and created an earth dam at the floor of the canyon. Subsequently in 1980, a lake, shown in the photos in Figure 6 near Slides 2 and 3, and a separate lake formed as shown in Figure 7 in undated oblique airphotos below Slide #5. These lakes that formed likely accelerated movement of the adjacent slides causing headward retreat of the slide scarps. This headward retreat endangered three residences on De Pauw Street (KBA, 1986). Several properties along the rim of


the canyon were damaged or endangered by landslides or slope distress during this period, including the subject property affected by Slide #5, with some of the structures, excluding the subject property, demolished due to the extent of the damage. In 1986, Kovacs-Byers and Associates (KBA) were retained by the Department of Recreation and Parks to conduct a geologic and soils engineering study to provide specific recommendations for the stabilization of the canyon (KBA, 1986). The exploration program included drilling with hollow stem auger as well as down-hole bucket augers for a total of 24 borings within the canyon. KBA also mapped the entire canyon and conducted extensive geotechnical testing of the samples obtained from exploration. The report retained the numbering system for the landslides first used by Moran, et al, and expanded it to include the other landslides mapped in the canyon. This report recommend that the canyon be filled to a depth of 75 feet and fill slopes be constructed in the area of landslides a 2:1 gradient (horizontal:vertical). Exploration activity and recommendations in the vicinity of the subject property are detailed further in section 5.3 of this report. Subsequent to the 1986 study, mass grading was initiated within the canyon following the recommendations of the 1986 report and under the direction of Kovacs-Byers and Associates initially and then the J. Byer Group, Inc. in the remaining years of grading. Grading to the configuration that existed in 2009 is described in the section 5.3. URS Corporation (URS) was retained by the Bureau of Engineering within the Department of Public works in 2009 to conduct additional geotechnical exploration and analysis to evaluate the results of the past grading within the canyon, current canyon stability, compile and incorporate all relevant prior geologic and geotechnical documents, and provide recommendations for additional stabilization measures. URS’s work culminated in a report, “Final Report – Geotechnical Investigation, Potrero Canyon Park, Pacific Palisades, City of Los Angeles, California,” dated February 17, 2010, that is further discussed in this report in Section 5.4. Subsequent to the URS, 2010 report, grading has been conducted in two areas of the canyon. The first area to be graded, from 2011-2013, was in the mouth area of the canyon adjacent to PCH (AMEC, 2013) and followed the slope stabilization recommendations of report prepared by Grover Hollingsworth and Associates, Inc. (GHA, 2007.) The second area of grading, conducted in late 2013, was in the northern section of the canyon below and including rear of the properties located at 15325, 15329, and 15333 De Pauw Street (LCI, 2013) following the slope stabilization recommendations of the report prepared by URS in 2010. 5.3 Review of Relevant RAP and Public Works Records Relating to Potrero

Canyon Grading

The following is a synopsis of information from relevant, readily available documents regarding the grading of Potrero Canyon in the area of the subject property subsequent to the 1979 slides described above. This review presented in this report is not intended to be an exhaustive description of all documents relating to the grading of Potrero


Canyon, but it does confer specific elements of the grading project and progress as they relate to the subject property.

The April 1, 1986 report by KBA summarizes the results of a study done for RAP that addressed stabilization of existing landslides in Potrero Canyon to develop a recreational area. Kovacs-Byer, under the direction of RAP, was selected to oversee the landslide mitigation and filling of the canyon. During the course of researching the grading work within Potrero Canyon, GEO has located and reviewed several interim compaction reports, letters, and memorandums. However, only limited records of in-grading geologic mapping have been found.

The canyon stabilization project was proposed to be conducted over three phases. The first phase primarily consisted of controlling the flow of groundwater by the installation of a storm drain and subdrain system in conjunction with horizontally drilled drains, or hydraugers. With the second phase, the canyon bottom was proposed to be filled to a depth of 75 feet with stabilization slopes constructed in the areas of sliding. The storm drain, subdrain, and planned fill detailed in the 1986 report have all been essentially completed in the area of the subject lot at this time up to the depths planned for phase II. By the early 2000’s, the planned phase III (BG, 1997, BG, 2000) had yet to be finished in the area of the subject lot and grading in the canyon stopped.

The 1986 exploration study conducted slope stability calculations that Byer concluded made it, “reasonable to assume that the proposed canyon fill, remedial grading, and subsurface drainage system will provide engineered fill slopes on the west side of the Potrero Canyon with a factor of safety in excess of 1.5. Stabilization of the landslides will be achieved.” (KBA, 1986). It was recommended that the upper 5 to 10 feet of the slide debris of the larger slides be removed and replaced with fill during grading to limit future infiltration of water into the slide masses left in place. A further recommendation was to trim all of the numbered slides to a 1:1 gradient. Based on consolidation testing of the slide debris samples, Byer concluded that the debris is, “not subject to excessive consolidation.” (KBA, 1986). Byer determined that, “deeper removals will not be necessary due to the well consolidated nature of the slide debris.” In cases where the slides were much smaller or shallower, KBA recommended complete removal and replacement with fill.

As part of the 1986 exploration study, two 8” hollow stem auger borings were advanced in the area of Slide #5. Boring 12 was advanced in the toe area of Slide #5 and boring 14 was advanced in the head of Slide #5 within Earlham Street. Boring 12 was drilled to a depth of 100 feet bgs, with landslide debris encountered composed of alluvial terrace, marine terrace, and Modelo Formation bedrock to a depth of 75 bgs overlying intact Modelo Formation. Groundwater was measured in Boring 12 at a depth of 53 feet bgs. Boring 14 was drilled to a depth of 110 feet bgs, with landslide debris encountered composed of alluvial terrace, marine terrace, and Modelo Formation bedrock to a depth of 40 bgs overlying intact Modelo Formation. Groundwater was measured in Boring 12 at a depth of 57 feet bgs. Exploration and mapping data were compiled to produce the geologic map, shown here as Figure 8, and several geologic cross sections relevant to the subject property shown herein as Figure 9. The mass of Slide #5 was estimated to


exceed 100,000 cubic yards. In the area of the subject property, historic/pre-historic activity of Slide #5 was noted in Kovacs-Byer’s review of air photos as early as 1949 (Byer, 1986).

It was postulated in the 1986 report, that the geologic structure of the canyon had not directly influenced the location of the landslides, but that it had influenced the movement and occurrence of groundwater in the area. It was concluded that the groundwater flow regime, “exerted a strong influence on the development of landsliding in the canyon.” (KBA, 1986)

Revised geologic maps with anticipated conditions and the recommended treatment for the temporary slopes were included in a supplemental report issued in 1988 (KBA, 1988.)

It was noted in a KBA, 1989 report that the hydraugers were placed laterally into the slopes horizontally up to 300 to 500 feet in the most active seep areas on the slopes of the canyon. Several bores were ‘usually’ drilled in a fan pattern from one location and then connected into a manifold to form an array of hydraugers that were then connected to the main canyon bottom subdrain. Approximately two miles of hydraugers were placed within the whole of Potrero Canyon. “Initial flow rates from the hydrauger bores were commonly 100 gallons per day apiece, though typically the rates declined rapidly.” The flow rates for hydrauger arrays E, F, and L, which were installed adjacent to the subject lot on Earlham Street were noted to have several drains with initial flow rates of 40,000 gallons a day. The ‘schematic’ origin point locations of these installed arrays and slope trim areas are shown here in Figure 10 and a more detailed location map is shown as Figure 11.

Prior to the installation of the hydraugers it was noted that excavation at the toe of Slide #5 was extremely difficult (KBA, 1989) and much of the alluvium and slide debris present at the existing grade of the toe of Slide #5 had to be left in place. “Excavations for dewatering sumps and test pits near the head of the tributary canyon revealed that a deep pocket of saturated alluvium and slide debris is present. Prior to the installation of dewatering sumps, all excavations in this area filled rapidly with water and could not be dug deeper than several feet before collapsing. After several weeks of pumping, test excavations were dug to a depth of 20 feet. No competent slide debris or bedrock was encountered. All excavations below the original grade were followed by continuous groundwater seepage from the freshly exposed surfaces of Slide 5.” Due to the hazards any removals presented, the canyon subdrain in the area was installed on the existing alluvium, not competent bedrock. The drainage of the alluvium at the head of the tributary canyon was to be accomplished with the installation of hydraugers penetrating the alluvium and a gravel blanket drain. Among the many hydraugers installed in the area of Slide #5, two drains were installed that extend under the subject property. New fill was then placed on alluvium and slide debris. A revised geologic map and cross section were presented in the 1989 report and reproduced here as Figure 12 and 13 respectively.


In an ‘Engineering Geologic Memorandum’ issued in July of 1990 Kovacs-Byer and Associates, Inc. stated that during Phase I grading, the installation of the storm drain and main canyon drain, “it was found that the side slopes of Potrero Canyon were potentially unstable above the 75 foot line.” It was then proposed to raise the canyon fill to 100 feet above the original flowline of Potrero Canyon and construct 2:1 (horizontal:vertical) slope buttress from that elevation to the rim of the canyon. (KBA, 1990b.)

In September of 1991, an ‘As-Built Geologic Conditions’ was issued by Kovacs-Byer and Associates, Inc., that detailed some of the problems with the grading of Slide #5. The report restated that the alluvium below the slide could not be removed without triggering a reactivation of the slide. The compacted fill overlying the slide was noted to, ‘not be certified for the support of any structures.’ Removal of Slide #5 debris was also noted to stop short of the eastern margin of Slide #5. (KBA, 1991b)

In June of 1993 an interim compaction report was filed by Kovacs-Byer and Associates, Inc.(KBA, 1993), that detailed work progress to date which included the area around Slide #5. The ‘progress’ map from this report is included herein as Figure 14.

By late 1993 Kovacs-Byer and Associates, Inc. had evolved into the J. Byer Group, Inc. which took over the responsibility of overseeing the grading operation of Potrero Canyon.

Phase II finish grade was reached in much of Potrero Canyon by the end of 1997 and progress up then was reviewed in a Phase III grading plan report (BG, 1997.) Slide #5 was stated as being too unstable to remove and recompact as any attempts at removal caused the slide to reactivate and any benching of Slide #5 was not recommended. It was noted again that compacted fill was placed ‘directly over the compressible, saturated, unstable alluvium at the toe of the slope’ as well as the landslide debris and that as such the fill would be considered non-structural. A map with the finish grade plan for Phase III that was present in several reports referencing Phase III grading (BG, 1997, BG, 1998, BG, 2000) that also show the recent phase of compaction testing locations is shown here in Figure 15.

An Interim Compaction Report was filed in January of 2000 that is the last report that deals with the canyon grading and compaction certification (BG, 2000). The remaining grading details contained in the report conform to standard practice for compaction reports certifying artificial fill and the slope buttresses were, “graded in accordance with the plans and permits approved by the City of Los Angeles Department of Building and Safety, Grading Section.” The fill covered by this report, not in the area of the subject property, was approved as primary structural fill by the City of Los Angeles on February 4, 2000 (CLA, 2000). The Byer Group report noted that the lots along the rim of the canyon that had been stabilized by compacted fill and stabilization fills were expected to support future residential development. The Byer Group recommended that each lot be investigated, “by an independent soil testing agency to provide project specific foundation recommendations.” In light of any future development, the report stated that,


“a complete file of geotechnical reports for the project will be maintained at the office of The J. Byer Group for outside consultants to review.”

5.4 2010 URS Report Description and Exploration in the area of 15206 Earlham Street

The 2010 URS report presented the results of a geotechnical investigation performed for the Potrero Canyon Park Project for BOE-GEO. The report provided findings from their review of existing geologic and geotechnical data; subsurface exploration; laboratory testing; their interpretation of the geologic and geotechnical conditions encountered; and provided recommendations for designing mitigation plans and constructing site improvements to repair and/or improve the Project slopes. To accomplish this they reviewed available existing geologic and geotechnical documents relative to the Park Project; performed geologic mapping of surface features; explored subsurface conditions by drilling and sampling seven (7) hollow stem auger borings (HS-1 and HS-3 through HS-8) and four (4) bucket auger borings (BA-4 and BA-6 through BA-8); excavated twenty-four (24) shallow test pits (TP-1 through TP-23 and TP-27); and performed laboratory testing on selected soil samples obtained from the exploration. From the data collected during the review, exploration, and testing phases, they evaluated potential settlement of the existing and proposed site materials; prepared geologic interpretations of the subsurface conditions (cross sections) from the reviewed data, geologic mapping, and field exploration; evaluated potential hazards of slope instability at various Project slopes; and performed engineering analyses used to provide geotechnical recommendations for the completion of the design and construction of the Park Project. A portion of the geologic map prepared by URS for the area of the subject property in question is included in Appendix A as Figure 16. As shown in Figure 16, URS advanced a bucket auger boring, BA-6, within the head mass of Slide #5 in Earlham Street. This boring was drilled and downhole logged to a depth of 39.5 feet below ground. This boring encountered fill to a depth of 14.5 feet, landslide debris overlying Modelo Formation bedrock at 30 feet, and groundwater at 23 feet below ground. URS also advanced a hollow stem auger boring in the toe area of Slide #5 to a depth of 101.5 feet below ground. This boring encountered fill to a depth of 79 feet, landslide debris comprised of Modelo Formation bedrock to the total depth of 101.5 feet, with groundwater not encountered during drilling. In the area of the subject property, URS prepared geologic cross sections S15, shown here as Figure 17, and S16 and S17, shown here as Figure 18. As shown in the portion of the geologic map, URS recommended the installation of a new hydrauger array to the west of the subject property in the main body of Slide #5, as well as a keyway and small buttress slope in the southern limits of the subject property. Any changes to the recommendations provided in the 2010 URS report that would become incorporated into the final grading plan would be subject to review and approval through LADBS.


For the complete boring or test pit logs or further information regarding testing, conclusions, reference list for documents relating to Potrero Canyon and its grading, and recommendations for any areas of Potrero Canyon adjacent to or including the property in question contained within the 2010 URS report, please review the complete report on file with LADBS.

5.5 History of Development and Geotechnical Exploration of 15206 Earlham Street and Adjacent Properties

In this section, we present a brief synopsis of past development and or private exploration on the City owned property and private properties in the area of Slide #5 that were encountered in LADBS records within the scope of this report. To that end, a review of the LADBS documents encountered for the city owned property as well as for adjacent properties will be presented. A bibliographic list of documents reviewed for each property is included in this section for ease of reference. The list of documents presented in this report may not represent all available records for the individual properties due in part to inconsistencies in City document filing procedures, changes in grading code document requirements, degradation of reproductions, etc. The review of documents was limited to those relevant to a geotechnical review, i.e., plumbing and electrical permits have not been obtained or reviewed for this report. This report does not evaluate conformance issues with building codes or whether proper permits were obtained for construction at the individual properties. 15206 Earlham Street- CITY PROPERTY City of Los Angeles (CLA), 1948. Affidavit Regarding Maintenance of Building and Uses for 15206 Earlham St. Document No. AFF 11240, dated March 25, 1948. City of Los Angeles (CLA), 1948. Certificate of Occupancy for 15206 Earlham St. Document No. 1974WL73090, dated August 24, 1948. City of Los Angeles (CLA), 1948. Certificate of Occupancy for 15206 Earlham St. Document No. 1947WL73091, dated August 24, 1948. City of Los Angeles (CLA), 1966. Application to Add-Alter-Repair-Demolish and for a Certificate of Occupancy for 15206 Earlham St. Document No. 1966WL63226, dated April 29, 1966. City of Los Angeles (CLA), 1968. Application to Add-Alter-Repair-Demolish and for a Certificate of Occupancy for 15206 Earlham St. Document No. 1968WL71314, dated February 16, 1968.


City of Los Angeles (CLA), 1969. Application to Add-Alter-Repair-Demolish and for a Certificate of Occupancy for 15206 Earlham St. Document No. 1969WL77196, dated May 13, 1969. City of Los Angeles (CLA), 1969. Certificate of Occupancy for 15206 Earlham St. Document No. 1969WL62778, dated May 14, 1969. City of Los Angeles (CLA), 1969. Certificate of Occupancy for 15206 Earlham St. Document No. 1969WL62779, dated May 14, 1969. The earliest record found for 15206 Earlham St. is an affidavit to build a shower in an accessory building in 1948. In 1948, two Certificates of Occupancies were issued for a dwelling and garage at the property. An application for a building permit was filed in 1966 that proposed to convert an existing garage into a den, increasing the size of a living area in a one family dwelling. The application and change to the plot plan are shown in Figure 19 and Figure 20, respectively. In 1968, an application for a building permit was filed that proposed to build a one story, two-car carport. Another application for a building permit was filed in 1969 to continue work on the carport. A Certificate of Occupancy was issued in 1969 for the conversion of the garage to a den. The certificate of Occupancy for the carport was also issued in 1969. 15200-15222 Earlham Street – Privately Owed Vacant Lots MEC/Geotechnical Engineers, Inc., 1999. Preliminary Geotechnical Engineering and Engineering Geology Investigation for 15200 Block of East Earlham Street, Pacific Palisades; Tract 9300; Lots 27, 28 , and 29 of Block 8 plus Lot 1 of Block 19; Los Angeles County. Document No. M12740020246- M12740020297, dated July 10, 1999. City of Los Angeles, 1999. Department Letter. 15200 Block of East Earlham Street, Pacific Palisades; Tract 9300; Lots 27, 28, and 29 of Block 8 plus Lot 1 of Block 19; Los Angeles County. Document No. M1274-002-0244- M1274-002-0245, dated August 5, 1999. MEC/Geotechnical Engineers, Inc., 2000. Addendum to Preliminary Geotechnical Engineering and Engineering Geology Investigation for 15200 Block of East Earlham Street, Pacific Palisades; Tract 9300; Lots 27, 28, and 29 of Block 8 plus Lot 1 of Block 19; Los Angeles County. Document No. M1321 004 0020- M1321 004 0025, dated September 18, 2000. City of Los Angeles, 2001. Revised Letter to Add Condition #1 and Revise Pile Requirements. 15200 Block of East Earlham Street, Pacific Palisades; Tract 9300; Lots 27, 28, and 29 of Block 8 plus Lot 1 of Block 19; Los Angeles County. Document No. M1333 002 0451- M1333 002 0453, dated April 25, 2001.


Discussion of these privately owned lots, which make up the main body of Slide #5 and are directly adjacent to the subject lot, are included in this report to illustrate the process of geotechnical exploration and reporting along with the review conducted by LADBS for new development on a known landslide. On July 10, 1999, MEC/Geotechnical Engineers, Inc. completed a Preliminary Geotechnical Engineering Investigation for the properties on 15200 block of Earlham Street. The investigation was completed to assess the feasibility of constructing 4 single-family residences on the lots. The subsurface investigation involved drilling four bore holes, using a bucket auger, to a depth of approximately 65 feet. The locations of the boring holes and a cross-section of the site can be seen in Figure 21 and Figure 22. The boring logs found in the report show that groundwater seepage was first encountered at approximately 20 feet below ground level. “The Geologic Outfit” performed the field exploration and the results were included as an attachment to the MEC report. The “Geologic Outfit” described the site geology as consisting of sedimentary bedrock, terrace deposits, colluvium, and fill. According to the “Geologic Outfit’ report, all landslide debris had been removed from the lots and non-structural fill was placed in the canyon. The report also stated that the site is “grossly stable” and no active faults are known to be present. On August 5, 1999, the City of Los Angeles Department of Building and Safety, Grading Division, issued a letter that rejected the original MEC report due to lack of sufficient information. The letter stated that recent borings and information in the Department archives suggest that the landslide debris was not removed and exists under the fill. LADBS requested an addendum to the report to be submitted including the following information: a detailed geologic map of the canyon fill and cross section of the site, a compaction report for the fill on the site and the LADBS approval letter for said report, and additional subsurface exploration of the site. The full list of requests can be found in the Department Letter (CLA, 1999). On September 18, 2000, MEC/Geotechnical Engineers, Inc. submitted addendum to the Department of Building and Safety, Grading Division. The addendum addressed the Departments questions from a meeting on September 6, 2000 but did not include any data from additional explorations. The revised map and cross section are shown here as Figure 23 and Figure 24 which show landslide debris under the street as well as the private property being studied. In April of 2001, CLA conditionally approved the report. The conditions state that no building permits can be issued to the subject sites until the following requirements have been met: the filling of the canyon in the area of the lots must be completed by the Department of Parks and Recreation and the final compaction report must be approved, the soil engineer must determine that all lateral movement of the buried landslide has stopped, the geologist and soils engineer shall review and approve detailed plans, and all roof and pad drainage shall be conveyed to the street. Additional conditions can be found in the department letter (CLA, 2001).


6.0 GEOLOGY

6.1 Geologic Setting

The site is located in the Pacific Palisades area of the City of Los Angeles and is approximately 1,600 feet north of the Pacific Ocean. Figure 25 shows the geology, from McGill, 1989. The regional area is dominated by wave cut terraces that are uplifted relative to the coastline, in part by the Potrero Canyon Fault. Elevations along the terraces generally exceed 200 feet above sea level. Erosion of the terraces has created deeply incised canyons such as Potrero Canyon, Temescal Canyon, and Las Pulgas Canyon. The older Pliocene and Miocene marine sedimentary bedrock that underlies the terrace deposits is folded and faulted and prone to landslides. This marine bedrock is generally fine grained consisting of silts and clays with lesser amounts of sand. Landslides have occurred on many of the descending slopes between the terraces and canyon bottoms.

6.2 Earth Units

Artificial Fill Fill placed during the RAP grading of the area as encountered by recent exploration has been described as consisting of layers of light to dark brown, mottled orange-brown, gray, gravelly to clayey, silty sands to sandy silts. The fill was observed to be moist and firm to very firm or dense Quaternary Landslides (Qls) Slide #5, as discussed in Section 5.3 above, occurred at the rear of the subject lot. It is interpreted to be initially caused by over steepening of the canyon walls from stream erosion. Much if not all of Slide #5 was reported to have been left in place during the grading of Potrero Canyon. As reported by URS, this debris was encountered in BA-6 at a depth of 14.5 feet below street grade which included landslide debris made up of terrace deposits and the Modelo Formation to a depth of 30 feet. Within the canyon, URS encountered debris at 79 feet below grade, made up Modelo Formation material to the total boring depth of 101.5 feet; the basal slide plane was not encountered in this boring.

Quaternary Alluvium (Qal) Alluvial deposits are present in the bottom of Potrero Canyon and consist of stream and slope wash deposits. Although some of the alluvium was removed and recompacted during canyon grading, it is estimated that as much as 20-30 feet of alluvium remains in some areas of the canyon floor, including the area below the subject lot at the toe of Slide #5.

Quaternary Terrace Deposits

Non-marine and marine terrace deposits cap the mesa upon which the surrounding tracts were developed. Their regional dip is to the south and groundwater may be perched in the lower sections atop the Pliocene or Miocene bedrock.

Quaternary Terrace Continental (Qtc) deposits at the site are primarily a yellowish-red, fine to coarse grained silty sands with interbedded gravelly sands


and sandy silts to sandy clays. In nearby areas is has been seen to contain a basal gravel layer. McGill, 1989 refers to these deposits as gravels, sands, silts and clays that are deposited in alluvial environments.

Quaternary Terrace Marine (Qtm) deposits at the site are primarily a light brown to red brown, poorly graded, medium grained, moist and dense sands deposited unconformably on the Pliocene or Miocene bedrock. The thickness is typically 10 feet or less. It is poorly indurated and prone to caving in boreholes. The poorly graded sand is highly permeable. The basal layers of the unit are known to contain variable concentrations of gravel and boulders.

Upper Miocene Modelo Formation (Tm) is a dark gray siltstone with interbedded fine-grained sandstone. The bedrock dips steeply between 70 to 90 degrees either north or south, generally striking northwest to northeast. McGill, 1989 found that joints in the bedrock are normal to bedding, predominantly near vertical, and north trending. McGill, 1989 also describes the bedrock as closely fractured to brecciated; commonly highly deformed or contorted; locally sheared, faulted and prone to deep seated landslides, especially along coastal palisades. 6.3 Geologic Structure

The bedding was mapped within the Miocene Modelo Formation bedrock in the area of the site by McGill, 1989 to strike roughly east-west and dip 55 degrees to the northeast. This orientation is considered ‘into slope’ with respect to the south or west facing slopes on the subject property.

McGill, 1989 mapped an anticlinal structure the Miocene bedrock on the canyon wall below the site with a plunge that trends away from the subject property to the southeast; the bedding within the Miocene bedrock dips approximately 40-50 degrees on either side of the anticlinal hinge.

6.4 Groundwater

Within Potrero Canyon, subsurface waters flow to the south and southeast towards the ocean. Numerous seeps at the marine terrace/bedrock contact were observed prior to the grading of the canyon and during exploratory drilling.

As noted in McGill, 1989, the regional groundwater flow is constrained by the marine platform contact between the terrace deposits and the underlying, less permeable bedrock formations. To further illustrate how the platform contact shapes groundwater flow and the resulting impact on slopes and landslides within the canyon, a portion of McGill’s 1989 platform contour map is reproduced herein as Figure 26.

The Kovacs-Byer January, 1986 Boring 12 encountered groundwater at a depth of 53 feet below ground surface (bgs) and Boring 14 encountered groundwater at a depth of 57 feet bgs. The URS February, 2009 boring BA-6 within Earlham Street encountered


groundwater at a depth of 23 feet bgs which the boring in the toe area of Slide #5, HS-8 did not encounter groundwater.

6.5 Seismic Hazards

The fault classification system adopted by the California Division of Mines and Geology (CDMG) now the California Geological Survey (CGS), relative to the State legislation delineating Earthquake Fault Zones along active or potentially active faults (Alquist-Priolo Act), is used for structures. CDMG defines an active fault (or fault zone) as a fault that has moved within Holocene time (about the last 11,000 years). Faults with no known displacement within Holocene time that showed evidence of movement during Quaternary time (the last 1.6 million years) have been defined as potentially active. In addition, the State has also established a Seismic Hazard Mapping Act to provide statewide seismic hazard mapping and a technical advisory program. The purpose of this legislation was to assist cities and counties in fulfilling their responsibilities for protecting the public health and safety from the effects of strong ground shaking, liquefaction, landslides, or other ground failure hazards caused by earthquakes. Ground surface rupturing along faults, ground shaking and liquefaction are three of the important seismic considerations for properties in Southern California. Faulting – Seismicity and Surface Rupture Southern California is an inherently seismically active region with numerous active faults. Due to this fact, this site, as with all areas of southern California, will experience strong ground shaking produced by future activity on regional faults. This ground shaking may result in significant damage which may include slope instability, structural distress, and differential settlement. The hazards posed by ground shaking for a moderate to large regional earthquake cannot be completely mitigated. However, no known active or in active faults underlie or trend towards the site. The site is not located within an Alquist-Priolo Earthquake Fault Zone. Also, no evidence of bedding offsets or displaced units can be found on or near the site. Thus, the risk of damage caused by fault surface rupture at the site is very low. Potrero Canyon Fault As mapped by McGill, 1989, the Potrero Canyon Fault is located approximately 1,400 feet south of the site. This fault is considered potentially active due to late Pleistocene movement on the fault and the recent activity (Point Mugu earthquake, 1973) on the southern frontal fault system, locally the Santa Monica Fault, which the Potrero Canyon Fault is a part. The CGS is currently reviewing the Potrero Canyon Fault and may zone it as ‘active’ in the future. Liquefaction According to the State of California Seismic Hazard Zones Map (State of California, 1997), the site is not located within an area that has potential for liquefaction.


Earthquake-Induced Landslides According to the State of California Seismic Hazard Zones Map (State of California, 1997), the site is located within an area that is susceptible and has the potential for earthquake-induced landslide activity. The Seismic Hazard Zones Map was based on the canyon topography that existed prior to the placement of fill within Potrero Canyon.

7.0 PROPERTY WALK-THROUGH The site at 15206 Earlham Street was visited by two geologists from GEO in March of this year. The inspections were intended to assist in evaluation of the overall condition of the dwellings, and the lot. The inspections were based on observations of the visible and apparent condition of the structures and their components on the date of the inspection and not a determination of future conditions. Such an inspection will not reveal every problem that exists or ever could exist, but only those material defects observed on the day(s) of the inspection(s). Note that, the fact that a structural element, system or subsystem is near, at, or beyond the end of the normal useful life of such a structural element, system or subsystem is not by itself a material defect. The following systems, structures, and components of the dwelling were inspected: A. Readily accessible and observable foundation B. The visible portions of the residence. C. Present conditions or indications of active water penetration. D. General indications of foundation movement or settlement that were observed, such as sheetrock cracks, concrete slabs, brick cracks, out-of-square door frames or floor slopes. No attempt has been made to determine the exact cause or timing of such indications, merely their presence. Photos taken of the City owned property covered by this report and are included as Appendix B. Discussed in the subsections below are the individual property and items of note that were observed during the site visit. The photos and text below are not intended to catalog every possible feature of distress found on the property, instead they provide a general overall condition as well as ‘type’ examples of distress. 7.1 15206 Earlham Street

According to City records, the single family residence at 15206 Earlham Street is a two bedroom, two bath dwelling with 1,656 square feet on a lot that is 10,341 square feet. The residence is a single story, with a partial basement accessed from the outside, wood frame stucco structure apparently founded on a combination of slab on grade and raised floor continuous spread footings with multiple pier footings. The slab on grade construction is newer than that of the rest of the structure and confined to the northern third of the residence. Within the structure there are currently 3 bedrooms in use (one of which is a pass-through room), 2 bathrooms, kitchen, living room, two carports, and a


semi-attached shed. The basement area is accessed from the exterior lower west side of the residence and is presently being used for storage. The house and property exhibited hairline cracks and some cracks up to or more than an inch wide associated with interior and exterior walls, ceilings, doorways, window frames, skylights, and tile and concrete flatwork as well as distress to retaining structures. Some of the exterior flatwork cracking was observed to be clearly associated with root development. Vertical or horizontal offsets or separations over one inch were associated with the cracks observed in some locations. The chimney of the structure was observed to relatively free of cracking and appeared to be in good condition. Considering the age of the structure, the residence is in generally fair condition, with most of the interior distress confined to the raised floor portion of the structure. The cracks noted in the structure during the site visit could be considered normal or above average for this type of construction due to minor settlement and earthquake shaking. However, the structure cracking seen does show two directions of movement: one in-line with the structure (roughly north-south) which is dominant and more pronounced, and the other towards the downslope direction to the west. Several of the earth retaining structures, both concrete walls and timber structures, on the property exhibited signs of distress through cracking, offsets, leaning, etc. The lot itself generally trends downslope away from the street in two directions, to the west towards the tributary canyon, and to the south towards the main Potrero Canyon. Due to this topographic trend, the residence and other associated improvements ‘straddle’ or are built into the side of a downslope ridge. Surface drainage on the property primarily flows south and to the west, but also underneath the structure through the crawlspace area. The current occupant stated that during at least one notable storm event, runoff drained from the property to east into the eastern side-yard and then under the central portion of structure. Evidence of this sub-structure runoff was seen in erosion and sedimentation around pier footings and a notable amount of efflorescence seen on foundation concrete and surrounding soils. Also, at least one pier footing appeared to be subject to concrete corrosion. The sub-structure runoff caused ponding of water in the lower western walled in ‘patio’ area, a condition which was later relieved by coring a hole in the concrete block wall to drain the area into the canyon. Roof drainage is collected by gutters and downspout systems and may at least partially be conveyed to the street by a sump system. A square concrete block was observed in the driveway that may contain a sump system, but this was not directly observed. In the middle and southern portions of the structure it appears that roof drainage may be conveyed away from the structure and possibly directed towards the canyon via sub-surface drain lines that were not observed. From a review of City records and observations made during the walk-through, there are apparently several possible encroachment issues with the subject property. The northern carport structure appears to encroach into the public right of way. The eastern property line of the subject property appears to have been surveyed recently as evidenced by staking and orange paint markings along the eastern side of the property. Based on NavigateLA data and the staking locations, portions of the northern shed


appear to encroach onto the property to the east. In the middle and southern portions of the of the subject property side-yard improvements as well as the structure of the property to the east (15202 Earlham Street) appear to encroach onto the subject property. The southern end of the lot contains some decking overlooking the canyon accessed through stairs leading down from the rear yard as well as a ‘rubble’ wall, in poor to fair condition, supporting an elevated vegetated ‘overlook’ area. Portions of the decking and the ‘overlook’ area may be present outside the southern property line. Adjacent to the subject property to the west are several vacant lots that appear to have been possibly surveyed recently as well as having a recent soils report on file with LADBS grading and hence may be developed in the near future. The exploration, analysis, and recommendations regarding this potential development are discussed further in Section 5.6 of this report. For additional details on the distress observed and a layout of the improvements on the subject property, please refer to the Plot Plan of the property included here as Figure 27. Photos of the subject property with further descriptions of items of note and examples of distress are included in this report as Appendix B, Photos 1-58. 8.0 REAL ESTATE DISCLOSURES

The following real estate disclosures are provided to inform potential buyers of covenants, conditions and restrictions on the purchase of the properties including those that are of record:

1. The sale excepts and reserves unto the City of Los Angeles all oil, gas, water and mineral rights now vested in the City of Los Angeles without, however, the right to use the surface of said land or any portion thereof to a depth of 500 feet below the surface, for the extraction of such oil, gas, water and minerals.

2. The sale is subject to covenants, conditions, restrictions, reservations, easements, encroachments, rights, and rights-of-way of record or which are apparent from a visual inspection of the real property and excepting and reserving to the City of Los Angeles any interest in the fee to the adjacent streets which would otherwise pass with the conveyance of the parcels of land. 3. The parcel maybe subject to one or more of the following items with regard to development of a site: Hillside Ordinance (168,159), Baseline hillside Ordinance, Slope/Density Ordinance, the City's coastal policies and requirements of the State Coastal Commission, prospective bidders are urged to investigate building restrictions and guidelines with the proper agencies prior to the auction.


4. Prospective buyers are further urged to investigate development problems associated with hillside and coastal properties as to geology, site grading, street access, drainage, availability of sewer and other public utilities. 5. No warranty or representation is made by the City of Los Angeles with respect to location, size, description of improvements or zone set out in the notice of the sale of the properties herein described; such data is being set forth for information only and is not, and shall not be deemed to be a part of the description by, or conditions of, which such properties will be offered for sale or sold. The City makes no representation or warranty whatsoever as to the condition or usability of the properties, the presence of any defects, whether apparent or hidden, or the fitness of the properties for use, or its fitness for a particular use. 6. Each property offered for sale is offered in an "AS IS" condition, and all bidders, by bidding on the property are, by such act, expressly agreeing to purchase the property in an "AS IS" condition and without any warranty as to fitness for use, fitness for a particular use, or condition of the property, and that the City of Los Angeles has no obligation to correct any condition of the property, whether known before or after the date of the auction. 7. An easement affecting the rear five (5) feet of said land for conduits and incidental purposes in favor of Palisades Corporation recorded in Book 20093, Page 81, Official Records. 8. Any other covenants, conditions, restrictions, easements, leases and notices of record. 9.0 REQUIREMENTS FOR GEOTECHNICAL INVESTIGATIONS WITHIN CITY

OWNED PROPERTIES

It is recommended that the successful bidder on any of the City owned properties commission a licensed California certified engineering geologist and geotechnical engineer to conduct a site specific geotechnical investigation of the property.

If the successful bidder wishes to conduct such an investigation prior to the close of escrow, a right of entry and excavation permits from the City of Los Angeles must be obtained. The granting of the right of entry is contingent upon GEO’s approval of proposed boring/test pit excavation and closure/filling procedures which shall be provided to GEO prior to the initiation of exploration activities. All borings within the city owned lots, streets, and Potrero Canyon will be required to be backfilled with 1-sack sand cement slurry and all cuttings are required to be removed from the site. It is required that GEO be notified 48 hours prior to any scheduled subsurface field exploration. Copies of all final logs of any geotechnical subsurface investigation must be provided to GEO prior to the completion of the sale of the property.


If the successful bidder chooses to conduct geotechnical investigation of the property subsequent to the close of escrow, the above requirements would not apply.

10.0 LIMITATIONS

The property walk-throughs were limited to observations of the properties of obvious signs of repairs or other conditions. The information provided in this report is based on observations and information gathered from sources which are believed to be reliable, but no attempt has been made to independently verify these observations and information and no guarantee or warranty is made as to the accuracy thereof. No liability is accepted for any loss, injury, liability or damage of any kind resulting in any way from (a) any errors or omissions of the observations and information (b) the unavailability, interruption or delay of the delivery of the observations and information to the client or third party, or (c) the use of these observations and information. This report is not a substitute for any third party documents or reports, such as appraisal reports, architectural plans, aerial photos, broker documents, contracts, engineers reports, environmental impact reports, escrow-sales documents, insurance documents, lease documents, legal documents, loan documents, phase I, II, or III reports, sheriff-police reports, property inspection reports, site surveys, property line surveys, soils reports, special studies, termite reports, title reports, or any other studies or documents. Any third party documents that have been referenced are assumed to be correct and no warranty is made as to their accuracy. By acceptance of this report, the recipient acknowledges that there is no guarantee or warranty as to the accuracy of this information. If the recipient of this report has any concerns regarding any items of disclosure, it is recommended that a qualified appraiser, architect, attorney, broker-agent, contractor, engineer, soils engineer, engineering geologist, environmental engineer, governmental agent, insurance agent, surveyor, contractor, property inspector or other professional be consulted.

This disclosure provides publicly available data. Depending on the project, review of additional state and local resources may be required to fully comply with standards. Customer proceeds at its own risk in choosing to rely on GEO’s disclosures, in whole or in part, prior to proceeding with any transaction. GEO cannot be an insurer of the accuracy of the information, errors occurring in conversion of data, or for customer’s use of data. GEO and the City of Los Angeles, officers, agents, employees and independent contractors cannot be held liable for accuracy, storage, delivery, loss or expense suffered by customer resulting directly or indirectly from any information provided by GEO.

The disclosures herein are made from a geotechnical standpoint only. A building contractor or others may make observations or come to conclusions that are different than those provided herein.

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11.0 SELECTED REFERENCES

AMEC, 2013. Compaction Report No. 2 for Certification of Rough Grading and Fill Placement Potrero Canyon Unit 1 Fill Stabilization Pacific Palisades, California, Grading Permit No. 10030.10000.02183. Dated June 6, 2013.

Buckley, Charles, 1987. Geology, Landslides and Slope Stabilization, Potrero Canyon Park, Pacific Palisades, California. Selected Landslides and Stabilization Projects of the Santa Monica Mountains, Los Angeles, California: Field Trip Guide Book. Dated June 20, 1987.

City of Los Angeles (CLA), 2000. Log # 29988. Department of Building and Safety Grading Division Approval letter for Soils Compaction Report No. JB 15600-B, dated January 28, 2000, prepared by J. Byer Group, Inc. Letter Dated February 4, 2000.

City of Los Angeles (CLA), 2014. Potrero Canyon Park: De Pauw Slope Remediation. Grading Plans Dated June 6, 2013.

Grover Hollingsworth and Associates, Inc., (GHA) 2007, “Geological and Soils Engineering Exploration, Proposed Stabilization Fill Slope Lots 15, 16, 17, and a Portion of Block 18, Block 1, Tract 9877, 211 and 231 Alma Real Drive, 1501 Pacific Coast Highway, And Potrero Canyon Park Pacific Palisades, California.” dated March 19, 2007, GH9892-G/GH12069-S.

J. Byer Group, Inc. (BG), 1994. Progress Report, Potrero Canyon Park Stabilization, Project #1012B, Lot 7, Tract 10426, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated September 7, 1994.

J. Byer Group, Inc. (BG), 1995a. Storm Damage Assessment, Potrero Canyon Park Stabilization, Project #1012B, Lot 7, Tract 10426, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated January 19, 1995.

J. Byer Group, Inc. (BG), 1995b. Interim Compaction Report, Potrero Canyon Park, Project #1012B, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated June 20, 1995.

J. Byer Group, Inc. (BG), 1996. Interim Compaction Report, Potrero Canyon Park, Project #1012B, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated February 28, 1996.

J. Byer Group, Inc. (BG), 1997. Plan Review and Update, Phase III Grading Plans, Potrero Canyon Park Stabilization, Portion of Lot 7, Tract 10426, 15101 Pacific Coast Highway, Pacific Palisades, California, Project No. 1012-B, Contract No. 2723. Dated December 17, 1997.


J. Byer Group, Inc. (BG), 1998. JB 15600-B Interim Compaction Report (2-26-1996 to 12-30-1998). Potrero Canyon Park, Los Angeles, California. Prepared for City of Los Angeles Department of Public Works Bureau of Engineering, Geotechnical Engineering Group Project No. 10190.002. Dated December 30, 1998.

J. Byer Group, Inc. (BG), 2000. Interim Compaction Report, Potrero Canyon Park Stabilization Project, Lot 7, Tract 10426, 15101 Pacific Coast Highway, Pacific Palisades, California, For the City of Los Angeles, Department of Building and Safety, Project #1012B, Contract #2723, The J. Byer Group Project Number JB 15600-B. Dated January 28, 2000.

Kovacs-Byer and Associates, Inc. (KBA), Unknown Date. Surface and Subdrain Plan, “As-Built” Map. Dated July 9, 1987 but date inconsistent with data presented on map.

Kovacs-Byer and Assoc., Inc. (KBA), 1986. Geologic and Soils Engineering Exploration, Potrero Canyon Park, Pacific Palisades, California. For Dept. of Recreation and Parks, City of Los Angeles, 1986.

Kovacs-Byer and Associates, Inc. (KBA), 1988. Supplemental Report, Alluvial Removal, Temporary Slopes and Subdrain Installation, Phase I, Project No. 1030B, Potrero Canyon Park, 15101 Pacific Coast Highway, Los Angeles, California. Dated October 27,1988.

Kovacs-Byer and Associates, Inc. (KBA), 1989, “Addendum Grading Report Lombard Canyon Subdrain Installation Potrero Canyon Park 15101 Pacific Coast Highway Los Angeles, California.” KB 9000-G, dated September 11, 1989.

Kovacs-Byer and Associates, Inc. (KBA), 1989. Addendum Grading Report, Slide 9 Remediation and Stabilization, Potrero Canyon Park, 15101 Pacific Coast Highway, Los Angeles, California. Dated June 15, 1989.

Kovacs-Byer and Associates, Inc. (KBA), 1990. Engineering Geologic Memorandum, Potrero Canyon Park, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated July 27, 1990.

Kovacs-Byer and Associates, Inc. (KBA), 1991a. Grading Memorandum. Potrero Canyon Park, Stabilization Project, Project No. 103B, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated July 10, 1991a.

Kovacs-Byer and Associates, Inc. (KBA), 1991b. As-Built Geologic Conditions, Potrero Canyon Park, Stabilization Project, Project No. 103B, 15101 Pacific Coast Highway, Pacific Palisades, California. Dated September 26, 1991.

Kovacs-Byer and Associates, Inc. (KBA), 1992. Progress Report, Potrero Canyon Park Stabilization, Project No. 1030-B, 15101 Pacific Coast Highway, Los Angeles, California. Dated December 17, 1992.


Kovacs-Byer and Associates, Inc. (KBA), 1993. Interim Compaction Report, Phase 2. Project No. 1030-B, 15101 Pacific Coast Highway, Los Angeles, California. Dated June 30, 1993.

Leighton Consulting, Inc. (LCI), 2013. Final Compaction Report: De Pauw Street Landslide Repair, 15325, 15329 and 15333 West De Pauw Street and Adjacent Portions of Potrero Canyon Park, Los Angeles, California. Prepared for City of Los Angeles Department of Public Works Bureau of Engineering, Geotechnical Engineering Group Project No. 10190.002. Dated December 30, 2013

McGill, John T., 1989, USGS. Geologic Maps of the Palisades Area, Los Angeles, California.

Moran, Proctor, Mueser & Rutledge, 1959. Final report, Pacific Palisades landslide study, Volume 1, 68 p; Volume 2, 45 p; Volume 3, 46 p., July 1959.

State of California, 1997. "Official Map of Seismic Hazard Zones, Topanga Quadrangle." Dated April 7, 1997, California. Department of Conservation, Division of Mines and Geology.

URS, 2010. Geotechnical Investigation Final Report: Potrero Canyon Park, Pacific Palisades, City of Los Angeles, California. Prepared for the City of Los Angeles, Department of Public Works, Bureau of Engineering, Geotechnical Engineering Group. URS project No. 29403821. Dated February 17, 2010.

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