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BRES2018-0411 Geotechnical ReportLA-NflMARK -• • and Geologists a MBE Company Gj�-5,# SerL November 30, 2018 Mr. Zeke Coronel Coronel Enterprises, Inc. 42760 Madio Street Indio, CA 92201 CITY OF LA OUINTA BUILDING DIVISION REVIEWED FOR CODE COMPLIANCE L DATEBY Dear Mr. Coronel: Cis`/ 780 N. 4th Street EI Centro, CA 92243 1760) 370-3000 landmark@landmark-ca.com 77-948 Wildcat Drive Palm Desert, CA 92211 (760) 360-0665 gchandra@landmark-ca.com J i7or Code CD n n[?1lcI1lC t 7i1esc pJ .j t. J `ar <<'.-!e CCFnpli. nCi_ 'fI U,_... -ii Geotechnical Report ;: t any v{c+la,ians of any 'Ns 773-360-002 & 621',!, �_• ��r=' I�:W�. 1a Quinta, California J Report No.: LPI8196 As requested, we are providing this geotechnical investigation report for the proposed new single- family residence project located at the north end of Casa Del Sol in La Quinta, California. The proposed development will consist of two new single-family residences with garages. These structures will be one story, wood/metal frame structures on shallow reinforced concrete foundations and slab -on -grade concrete floors. Site Conditions The project site is rectangular shaped in plan view, elongated in the east -west direction, and is sloping gently to the east. The project complex site is bounded by Avenida Montezuma, a residential paved roadway to the south and Bear Creek Trail to the north. Adjacent residential properties are flat -lying and are approximately at the same elevation with this site. Recommendations It is our opinion that the findings and professional opinions in the referenced geotechnical investigation report for APN 773-360-13, prepared by our office dated Jul S - W_FD applicable for this proposed project. CITY QUIN Q0Mr-1LJ 'i- li. APNs 773-360-02 & 23, La Quinta, CA Closure LCI Report No.: LP 18196 We have prepared this report for your exclusive use in accordance with the generally accepted geotechnical engineering practice as it existed within the site area at the time of our study. No warranty is expressed or implied. It should be noted that the submitted plans were not reviewed for conformance with other clients, governmental or consultant requirements. We appreciate the opportunity to be of service. Should you have any questions, please call our office at (760)360-0665. Sincerely Yours, LandMark Consultants, Inc. 0 Greg M. 'Vneer M.ASCE Principa E: pF ESS/O D � M. C ftg1b 1�2 No. C 34432 M LOF Attachments: Appendix A: Geotechnical Report for APN 773-360-013, Dated July 25, 2018 LandMark Consultants, Inc. Page 2 ,1 LANDMARK a MBE Company July 25, 2018 Mr. Zeke Coronel Coronel Enterprises, Inc. 42760 Madio Street Indio, CA 92201 Geotechnical Report APN 773-360-013 La Quinta, California LCI Report No.: LP18112 Dear Mr. Coronel: 780 N. 4th Street EI Centro, CA 92243 1760) 370-3000 landmark@landmark-ca.com 77-948 Wildcat Drive Palm Desert, CA 92211 1760) 360-0665 gchandra@landmark-ca.com As per your request, LandMark Consultants, Inc. is providing the following geotechnical report for the proposed 3,156 square foot single family residential project located at 77-137 Casa Del Sol in La Quinta, California. The proposed development will consist of new single family residential home with a garage, concrete driveway and swimming pool. The new home and garage will be one story, wood and metal frame structure with shallow reinforced concrete foundations and slab - on -grade concrete floors. Purpose of Work The purpose of this study was to investigate the upper 14.5 feet of subsurface soil at selected locations within the site for evaluation of physical/engineering properties. From the analysis of the field and laboratory data, professional opinions were developed and are provided in this report regarding geotechnical conditions at this site and the effect on design and construction. Field Exploration Subsurface exploration was performed on June 22, 2018 using a backhoe to excavate two (2) exploratory test pits to an approximate depth of 14.5 feet below the existing ground surface. The test pits locations are shown on the Site and Exploration Plan (Plate A-2). Bulk samples were obtained at selected depths in the test pits. The test pits were located by taped or paced measurements and should be considered approximate. APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 A senior engineer maintained logs of the test pits during exploration. The logs were edited in final form after a review of retrieved samples and the field and laboratory data. The test pit logs are presented on Plates B-1 and B-2 in Appendix B. Soils encountered have been classified according to the Unified Soil Classification System. A key to the test pit logs is presented on Plate B-3. The stratification lines shown on the subsurface logs represent the approximate boundaries between the various strata. However, the transition from one stratum to another may be gradual over some range of depth. After logging and sampling the soil, the exploratory test pits were backfilled with the excavated material. The backfill was loosely placed and was not compacted to the requirements specified for engineered fill. Laboratory Testing Laboratory tests were conducted on selected bulk soil samples to aid in classification and evaluation of selected properties of the site soils. The tests were conducted in general conformance to the procedures of the American Society for Testing and Materials (ASTM) or other standardized methods as referenced below. The laboratory testing program consisted of the following tests: ■ Grain Size Analysis (ASTM D422) — used for soil classification ■ Moisture -Density Relationship (ASTM D1557) — used for soil compaction determinations • Chemical Analyses (soluble sulfates & chlorides, pH, and resistivity) (Caltrans Methods) — used for concrete mix evaluations and corrosion protection requirements The laboratory test results are presented on the subsurface logs and on Plates CA through C-3 in Appendix C. Engineering parameters of soil strength, compressibility, and relative density utilized for developing design criteria provided within this report were extrapolated from data obtained from the field and laboratory testing program. LandMark Consultants, Inc. Page 2 1 "1 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Site Conditions The project site is rectangular shaped in plain view, elongated in the east -west direction, and is relatively flat -lying vacant lot. The subject is located on the south side of Casa Del Sol west of Avenida Madero. Both streets are paved two-lane residential streets. Adjacent properties are flat - lying and are approximately at the same elevation with this site. Single-family residences and vacant lots are scattered around the project site. A flood channel is located approximately 200 feet to the northwest. The project site lies at an elevation of approximately 70 to 72 feet above mean sea level (AMSL) in the Coachella Valley region of the California low desert. Annual rainfall in this and region is less than 4 inches per year with four months of average summertime temperatures above 100 °F. Winter temperatures are mild, seldom reaching freezing. Subsurface Soils Subsurface soils encountered during the field exploration conducted on June 22, 2018 consist of dry, medium dense silty sand/sand (SM/SP). The near surface soils are non -expansive in nature. The subsurface logs (Plates B-1 and B-2) depict the stratigraphic relationships of the various soil types. Groundwater Groundwater was not encountered in the borings during the time of exploration. According to Coachella Valley Water District (CVWD) readings of groundwater levels from nearby wells, groundwater is located at a depth between approximately 70 and 85 feet below the ground surface in the vicinity of the project site. There is uncertainty in the accuracy of short-term water level measurements. Groundwater levels may fluctuate with precipitation, irrigation of adjacent properties, drainage, and site grading. The groundwater level noted should not be interpreted to represent an accurate or permanent condition. Based on the regional topography, groundwater flow is assumed to be generally towards the north- west within the site area. Flow directions may vary locally in the vicinity of the site. LandMark Consultants, Inc. Page 3 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Geologic Setting The project site is located in the Coachella Valley portion of the Salton Trough physiographic province. The Salton Trough is a geologic structural depression resulting from large scale regional faulting. The trough is bounded on the northeast by the San Andreas Fault and Chocolate Mountains and the southwest by the Peninsular Range and faults of the San Jacinto Fault Zone. The Salton Trough represents the northward extension of the Gulf of California, containing both marine and non -marine sediments since the Miocene Epoch. Tectonic activity that formed the trough continues at a high rate as evidenced by deformed young sedimentary deposits and high levels of seismicity. Figure 1 shows the location of the site in relation to regional faults and physiographic features. The surrounding regional geology includes the Peninsular Ranges (Santa Rosa and San Jacinto Mountains) to the south and west, the Salton Basin to the southeast, and the Transverse Ranges (Little San Bernardino and Orocopia Mountains) to the north and east. Hundreds of feet to several thousand feet of Quaternary fluvial, lacustrine, and aeolian soil deposits underlie the Coachella Valley. The southeastern part of the Coachella Valley lies below sea level. In the geologic past, the ancient Lake Cahuilla submerged the area. Calcareous tufa deposits may be observed along the ancient shoreline as high as elevation 45 feet above mean seal level (AMSL) along the Santa Rosa Mountains from La Quinta southward. Lacustrine (lake bed) deposits comprise the subsurface soils over much of the eastern Coachella Valley with alluvial outwash along the flanks of the valley. Faulting The project site is located in the seismically active Coachella Valley of southern California with numerous mapped faults of the San Andreas Fault System traversing the region. We have performed a computer-aided search of known faults or seismic zones that lie within a 44 -mile (71 kilometer) radius of the project site (Table 1). A fault map illustrating known active faults relative to the site is presented on Figure 1, Regional Fault Map. Figure 2 shows the project site in relation to local faults. The criterion for fault classification adopted by the California Geological Survey defines Earthquake Fault Zones along active or potentially active faults. LandMark Consultants, Inc. Page 4 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 An active fault is one that has ruptured during Holocene time (roughly within the last 11,000 years). A fault that has ruptured during the last 1.8 million years (Quaternary time) but has not been proven by direct evidence to have not moved within Holocene time is considered to be potentially active. A fault that has not moved during Quaternary time is considered to be inactive. Review of the current Alquist-Priolo Earthquake Fault Zone maps (CGS, 2000a) indicates that the nearest mapped Earthquake Fault Zone is the San Andreas -San Bernardino (South) fault located approximately 8.7 miles northeast of the project site. General Ground Motion Analysis The project site is considered likely to be subjected to moderate to strong ground motion from earthquakes in the region. Ground motions are dependent primarily on the earthquake magnitude and distance to the seismogenic (rupture) zone. Acceleration magnitudes also are dependent upon attenuation by rock and soil deposits, direction of rupture and type of fault; therefore, ground motions may vary considerably in the same general area. CBC General Ground Motion Parameters: The 2016 CBC general ground motion parameters are based on the Risk -Targeted Maximum Considered Earthquake (MCER). The U.S. Geological Survey "U.S. Seismic Design Maps Web Application" (USGS, 2018) was used to obtain the site coefficients and adjusted maximum considered earthquake spectral response acceleration parameters. The site soils have been classified as Site Class D (stiff soil profile). Design spectral response acceleration parameters are defined as the earthquake ground motions that are two-thirds (2/3) of the corresponding MCER ground motions. Design earthquake ground motion parameters are provided in Table 2. A Risk Category II was determined using Table 1604.5 and the Seismic Design Category is D since Si is less than 0.75. The Maximum Considered Earthquake Geometric Mean (MCEc) peak ground acceleration (PGAM) value was determined from the "U.S. Seismic Design Maps Web Application" (USGS, 2018) for liquefaction and seismic settlement analysis in accordance with 2016 CBC Section 1803.5.12 and CGS Note 48 (PGAM = FPcn*PGA). A PGAm value of 0.528 has been determined for the project site. LandMark Consultants, Inc. _ Page 5 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Seismic and Other Hazards ► Groundshaking. The primary seismic hazard at the project site is the potential for strong groundshaking during earthquakes along the San Andreas Fault. A further discussion of groundshaking follows above. ► Surface Rupture. The project site does not lie within a State of California, Alquist-Priolo Earthquake Fault Zone. Surface fault rupture is considered to be unlikely at the project site because of the well -delineated fault lines through the Coachella Valley as shown on USGS and CDMG maps. However, because of the high tectonic activity and deep alluvium of the region, we cannot preclude the potential for surface rupture on undiscovered or new faults that may underlie the site. ► Liquefaction. Liquefaction is unlikely to be a potential hazard at the site, due to groundwater deeper than 50 feet (the maximum depth that liquefaction is known to occur). Other Potential Geolo is Hazards: ► Landsliding. The hazard of landsliding is unlikely due to the regional planar topography. No ancient landslides are shown on geologic maps of the region and no indications of landslides were observed during our site investigation. ► Volcanic hazards. The site is not located in proximity to any known volcanically active area and the risk of volcanic hazards is considered very low. ► Tsunamis, sieches, and flooding. The site does not lie near any large bodies of water, so the threat of tsunami, sieches, or other seismically -induced flooding is unlikely. The site is located within Other Flood Areas, Zone X (as shown on Plate A-8). The areas of 1% annual chance flood with average depth of less than 1 foot or with drainage area less than I square mile. ► Expansive soil. The near surface soils at the project site consist of silty sands/sands which are non -expansive. Site Preparation Clearing and Grubbing.: Any surface improvements, debris or vegetation including grass, brush, and weeds, on the site at the time of construction should be removed from the construction area. Root balls should be completely excavated. Organic stripping should be hauled from the site and not used as fill. Any trash, construction debris, and buried obstructions such as sprinkler and leach lines exposed during rough grading should be traced to the limits of the foreign material by the grading contractor and removed under our supervision. Any excavations resulting from site clearing should be dish -shaped to the lowest depth of disturbance and backfilled under the observation of the geotechnical engineer's representative. LandMark Consultants, Inc. Page 6 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Iiuilduip Pad Preparation_ The existing surface soil within the proposed building pad should be removed to 18 inches below the lowest foundation grade or 36 inches below the original grade (whichever is deeper), extending five feet beyond all exterior wall/column lines (including adjacent concrete areas). Exposed sub -grade should be scarified to a depth of 8 inches, uniformly moisture conditioned to at least 2% over optimum moisture content and re -compacted a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. The native granular soil is suitable for use as compacted fill and utility trench backfill. The native soil should be placed in maximum 8 inches lifts (loose), uniformly moisture conditioned to at least 2% of optimum moisture content, and re -compacted to a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. Imported fill soil (if needed) should similar to onsite soil or non -expansive, granular soil meeting the USCS classifications of SM, SP -SM, or SW -SM with a maximum rock size of 3 inches. The geotechnical engineer should approve imported fill soil sources before hauling material to the site. Imported granular fill should be placed in lifts no greater than 8 inches in loose thickness, uniformly moisture conditioned to at least 2% over optimum moisture content, and re -compacted to a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods. In areas other than the house pad which are to receive concrete slabs and pavements, the ground surface should be over -excavated to a depth of 18 inches, uniformly moisture conditioned to at least 2% over optimum moisture content, and re -compacted to a minimum of 90% of the maximum density determined in accordance with ASTM D1557 methods Soil Bearing Values and Lateral Loads The subsurface soils consist of sand with some gravel to maximum penetrated. An allowable soil bearing pressure of 1,800 psf could be used. Passive resistance of lateral earth pressure may be calculated using an equivalent fluid pressure of 350 pcf to resist lateral loadings. The top one foot of embedment should not be considered in computing passive resistance unless the adjacent area is confined by a slab or pavement. An allowable friction coefficient of 0.4 may also be used at the base of the footings to resist lateral loading. Static earth pressure equivalent to that exerted by a fluid weighing 35 pcf for unrestrained (active) conditions and 50 pcf for restrained (at -rest) conditions. LandMark Consultants, Inc. Page 7 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Foundation All exterior and interior foundations should be embedded a minimum of 12 inches deep. Continuous wall footings should have a minimum width of 12 inches. Spread footings should have a minimum width of 24 inches and should not be structurally isolated. Recommended concrete reinforcement and sizing for all footings should be provided by the structural engineer. Slabs -on -Grade Concrete slabs and flatwork should be a minimum of 4 inches thick. The concrete floor slabs may either be monolithically placed with the foundation or dowelled after footing placement. The concrete slabs may be placed on granular subgrade that has been compacted at least 90% relative compaction (ASTM D1557). Slab thickness and steel reinforcement should be determined by the design engineer. American Concrete Institute (ACI) guidelines (ACI 302.1R-04 Chapter 3, Section 3.2.3) provide recommendations regarding the use of moisture barriers beneath concrete slabs. The concrete floor slabs should be underlain by a 10 -mil polyethylene vapor retarder that works as a capillary break to reduce moisture migration into the slab section. All laps and seams should be overlapped 6 -inches or as recommended by the manufacturer. The vapor retarder should be protected from puncture. The joints and penetrations should be sealed with the manufacturer's recommended adhesive, pressure -sensitive tape, or both. The vapor retarder should extend a minimum of 12 inches into the footing excavations. The vapor retarder should be covered by 4 inches of clean sand (Sand Equivalent SE>30) unless placed on 2.5 feet of granular fill, in which case, the vapor retarder may lie directly on the granular fill with 2 inches of clean sand cover. Placing sand over the vapor retarder may increase moisture transmission through the slab, because it provides a reservoir for bleed water from the concrete to collect. The sand placed over the vapor retarder may also move and mound prior to concrete placement, resulting in an irregular slab thickness. For areas with moisture sensitive flooring materials, ACI recommends that concrete slabs be placed without a sand cover directly over the vapor retarder, provided that the concrete mix uses a low-water cement ratio and concrete curing methods are employed to compensate for release of bleed water through the top of the slab. The vapor retarder should have a minimum thickness of 15 -mil (Stego-Wrap or equivalent). LandMark Consultants, Inc. Page 8 APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 Control joints should be provided in all concrete slabs -on -grade at a maximum spacing (in feet) of 2 to 3 times the slab thickness (in inches) as recommended by American Concrete Institute (ACI) guidelines. All joints should form approximately square patterns to reduce randomly oriented contraction cracks. Contraction joints in the slabs should be tooled at the time of the pour or sawcut ('/4 of slab depth) within 6 to 8 hours of concrete placement. Construction (cold) joints in foundations and area flatwork should either be thickened butt joints with dowels or a thickened keyed joint designed to resist vertical deflection at the joint. All joints in flatwork should be sealed to prevent moisture, vermin, or foreign material intrusion. Precautions should be taken to prevent curling of slabs in this and desert region (refer to ACI guidelines). All independent concrete flatworks should be underlain by 12 inches of moisture conditioned and compacted soils. All flatwork should be jointed in square patterns and at irregularities in shape at a maximum spacing of 10 feet or the least width of the sidewalk. Concrete Mixes and Corrosivity Selected chemical analyses for corrosivity were conducted on bulk samples of the near surface soil from the project site (Plate C-2). The native soils have low levels of sulfate and chloride ion concentrations. Resistivity determinations on the soil indicate a severe potential for metal loss because of electrochemical corrosion processes. A minimum of 2,500 psi concrete of Type II Portland Cement with a maximum water/cement ratio of 0.60 (by weight) should be used for concrete placed in contact with native soil on this project (sitework including streets, sidewalks, driveways, patios, and other wall foundations). Landmark does not practice corrosion engineering. We recommend that a qualified corrosion engineer evaluate the corrosion potential on metal construction materials and concrete at the site. Observation and Density Testing Site preparation and fill placement should be continuously observed and tested by a representative of a qualified geotechnical engineering firm. Near full-time observation services during the excavation and scarification process is necessary to detect undesirable materials or conditions and soft areas that may be encountered in the construction area. The geotechnical firm that provides observation and testing during construction shall assume the responsibility of "geotechnical engineer of record" and, as such, shall perform additional tests and investigation as necessary to satisfy themselves as to the site conditions and the recommendations for site development. LandMark Consultants, Inc. Page 9 t I APN 773-360-013 — La Quinta, CA LCI Report No. LP 18112 We did not encounter soil conditions that would preclude implementation of the proposed project provided the recommendations contained in this report are implemented in the design and construction of this project. We appreciate the opportunity to provide our findings and professional opinions regarding geotechnical conditions at the site. If you have any questions or comments regarding our findings, please call our office at (760) 360-0665. Respectfully Submitted, LandMark Consultants, Inc. P.E., M.ASCE �;�oF ESS/d 0 m LU a No. C 34432 M CIVI �YOF rA Attachments: Appendix A: Vicinity and Site Maps Appendix B: Subsurface Soil Logs and Soil Key Appendix C: Laboratory Test Results Appendix D: References LandMark Consultants, Inc. Page 10 77137 Casa del Sol -- La Quinta, CA LCI Project No. LPI 8112 Table 1 Summary of Characteristics of Closest Known Active Faults Fault Name Approximate Distance (miles) Approximate Distance (km) Maximum Moment Magnitude (MW) Fault Length (km) Slip Rate (mm/yr) San Andreas - San Bernardino (South) 8.7 13.9 7.4 103 t 10 30 = 7 San Andreas - Coachella 8.7 13.9 7.2 96 f 10 25 t 5 San Andreas - San Bernardino (North) 8.8 14.0 7.5 103 t 10 24 f 6 Indio Hills * 10.1 16.1 Garnet Hill * 14.2 22.8 Blue Cut * 16.7 26.7 San Jacinto - Anza 17.0 27.1 7.2 91 f 9 12 t 6 San Jacinto - Coyote Creek 18.9 30.2 6.8 41 t 4 4 f 2 Eureka Peak 19.8 31.7 6.4 19 t 2 0.6 t 0.4 Burnt Mtn. 27.1 43.3 6.5 21 f 2 0.6 t 0.4 Morongo * 29.5 47.2 Pinto Mtn. 31.2 49.9 7.2 74 t 7 2.5 f 2 Hot Springs * 33.4 53.5 San Jacinto - Borrego 33.5 53.6 6.6 29 f 3 4 t 2 Landers 34.4 55.1 7.3 83 f 8 0.6 f 0.4 Pisgah Mtn. - Mesquite Lake 35.5 56.8 7.3 89 f 9 0.6f 0.4 San Jacinto - San Jacinto Valley 36.6 58.5 6.9 43 f 4 12 t 6 Earthquake Valley 37.3 59.8 6.5 20 f 2 2 f 1 Elsinore - Julian 39.9 63.8 7.1 76 f 8 5 f 2 S. Emerson - Copper Mtn. 42.9 68.6 7 54 f 5 0.6 f 0.4 Johnson Valley (northern) 43.8 70.1 6.7 35 f 4 0.6 f 0.4 Elsinore - Temecula 44.2 70.8 6.8 43+4 5 f 2 * Note: Faults not included in CGS database_ 9 77137 Casa del Sol -- La Quinta. CA LCI Proiect No. LPI 8112 Table 2 2016 California Building Code (CBC) and ASCE 7-10 Seismic Parameters CBC Reference Soil Site Class: D Table 20.3-1 Latitude: 33.6733 N Longitude: -116.3186 W Risk Category: 11 Seismic Design Category: D Maximum Considered Earthquake (MCE) Ground Motion Mapped MCE� Short Period Spectral Response S, 1.500 g Figure 1613.3.1(1) Mapped MCER I second Spectral Response S, 0.601 g Figure 1613.3.1(2) Short Period (0.2 s) Site Coefficient Fe 1.00 Table 16133.3(1) Long Period (1.0 s) Site Coefficient F� 1.50 Table 1613.3.3(2) MCE,? Spectral Response Acceleration Parameter (0.2 s) SMs 1.500 g = F, * S, Equation 16-37 MCEF Spectral Response Acceleration Parameter (1.0 s) Sh„ 0.902 g = F,. * S, Equation 16-38 Design Earthquake Ground Motion 0.12 sec =0.2*SD,/SDS Design Spectral Response Acceleration Parameter (0.2 s) SDs 1.000 g = 2/3*S,%,s Equation 16-39 Design Spectral Response Acceleration Parameter (LO s) SDS 0.601 g = 2/3*S,,{i Equation 16-40 Risk Coefficient at Short Periods (less than 0.2 s) CHs 1.066 1.00 ASCE Figure 22-17 Risk Coefficient at Long Periods (greater than 1.0 s) CR, 1.029 0.60 ASCE Figure 22-18 1.50 Ti, 8.00 sec - :_.. i ASCE Figure 22-12 To 0.12 sec =0.2*SD,/SDS ._ 0.75 TS 0.60 see =SD,/SDS Peak Ground Acceleration PGAM 0.52 g 1.13 ASCE Equation 11.8-1 1.6 1.4 .. { :....: . - Period T (sec) Sa (g) MCEa Sa (9) 0.12 1.00 1.50 .. - - 0.60 1.00 1.50 1.2 :- - :_.. i - ._ 0.75 080 1.20 w-' -- 0.60 075 1.13 d 1.0 0 -._ .. 0.90 0.67 1 00 0.8 1.00 1.10 0.60 0.90 0.55 0.62 -=- 1.20 0.50 0.75 0.6 - 1.20 0.50 0.75 - - ........ _: ! -- 140 0.43 0.64 rn 0.4 - - - 1.50 0.40 0.60 1 75 0.34 052 0.2 . . . . . - - --- 2.00 0.30 0.45 - _ ..., 2.20 0.27 0.41 0.0 .. . .......71T 7 - - _ 240 0.25 0.38 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 2.60 0.23 0.35 Period (see) 280 0.21 0.32 300 0.20 0.30 MCER Response Spectra Design Response Spectra 3.50 0.17 0.26 4.00 0.15 0.23 20 fN , —S 50 ken 4 � . Source: California Geological Survey 2010 Fault Activity Map of California http:/lwww.quake.ca.gov/gmaps/FAMIfaultactivitymap.html# LANDMARK. Project No.:,LP18112 Regional Fault Map Figure 1 � '~~ � ai►� r Lake, r'Havasu Valley Gley' C i Jashua "free ,E saF-Pork nts f �• ` l Sea 1 — 14 4_ Rara wley iSTR16 K � . a niee .. o 8� 4 El Calm A ti Sta,tr ecata� Mexicali -- - .+-- .� ' Siniluis t � lana - r Map � dataM Golfo, INEGI - Source: California Geological Survey 2010 Fault Activity Map of California http:/lwww.quake.ca.gov/gmaps/FAMIfaultactivitymap.html# LANDMARK. Project No.:,LP18112 Regional Fault Map Figure 1 r f oshua Tree �j JW f Yilwl Park Source: California Geological Survey 2010 Fault Activity Map of California http://www.quake.ca.govlgmaps/FAM/faultactivitymap.html# LANWARK Project No.: LP18112 IF - Map of Local Faults Figure 2 1. 1 EXPLANATION Fault laces on land are Indaled by solid lines cated, lus whole well loby dashed line where aWairmatela• located or infl,red and W coned Icon where concealed by younger rocks or W lakes w bays Fault traps re queued More conenuatim or existence is uncertain Concealed faults In the Great Valley ane based on maps of selected subsurface honzori so locations shown are approximate and may indole M dual ;rend any All dhllprn llz Dssed=ris►slr mU"dri"A reggae:>_!annxcy try ww d.sq defined dashed there inlwreq querietlwhere uneeda.n FAULT CLASSIFICATION COLOR CODE (hdicaling Rcccrnc. of Mas'mint Fault along which historic IIas1200 years) tlrsplac li hes o5urred and is associated with me or mare It the following la) a rA "'d cental win "'i"th" (Aso a cluaed a1! same veaadrfli lura- book.caused by ground ihaaing during earthquakes, • It extensive ground breakage, not on IM white wolf taut caused b the Arvin-Tahachopi earthquake of 1952) The dale of the associated earthquake is Indcated Wher. repealed surface ruptures on the some fault have occurred, only the dais of the latest movement may tie indicated. especially if senior reports are nor well documented as to location of found freaks (b) fault creep slippage - slow ground daplacement usually without accompanying earthquakes (c) daplacnd surrey lines A Inangle to the right or left of the dii Indcatrs elimination pant of observed sudau dsplacemenl Solid red triangle indicates known location of ruptwe termination pont Open elaek triangle Indoles uncedren or estimated facet of rupture lerminawion point Oaile prep led tit IX wrgles iriseres tial fsdlk haat No triangle by date IndcalH an INenmediale point along fault break Faust nglenla!e laull :zees 4ppap Hrnutes:ndrsul linear ew!ent or fti- 'n M A—lxtos fuer, swm leader) nnii es nepresen!abve Isc45rme where fault creep has been observed and recorded Squale an fault in dotes where fault creep slippage has oceured mat has assn tiggeed by an aimhquake ansomeotheri Date of causative earthquake lndcated Squ—to dight and left pf date indcate Ill not points between which triggered seep slippage has occurred (creep either 9nbnuos or intermittent between these and punts) Holocene fault ylsplacomenl (during pail 11,730 years) Anti historic record Geanorpnlc eviden- to: Holocene Ili includes sag pond; scarps shwving little erosion. or the foegvinp r.stunas in Holocene age deposits: offset stream muses, linear scm^shutter ridges and triangular Imported span Recency of resulting offshore is based an the intrrprelnd age of the youngest sure!. displaced by faulting Late Oualwnary fall displacement (during past 700,000 years) Geomorphic eviderre simiar to that described for Holocene faults eecepr features are less dstind Faulting may be younger, but lack of younger overlying deposits precludes more accurate age cfassAiwahnn Ouaterruy fault (age undillerenoaled) Most fault, of this category show evidence of displacement some- time during the pest 15 million yews, peal -captions are faults which displace rocks of undperenti. eked Rno•Pleismeene age Unnumbsr.d Ousternary faults were based on Fault Map of California 1975 See Burman 201, Appends D for sorxce data Pr."tuderrrary fault (older that 16 million yeas) or fault without recognized Quaternary daplacemem Same faults are shown In this category because the source of mapping used was dreparm isance nature, or was not done with the ob)ect of dating fault dsplauments F.A. In this category are not necessarily inactive ADDITIONAL FAULT SYMBOLS Bar and ball on downmswn side (relative or apparent) Arrows along fault rndcale relative or apparent direction of lateral movement Arrow on fault indicates drectibn or dip Lowangle fault (barba on upper plate) Fault sudace generally diIe- than 45' our locally may have been subspuaMly steepened On offshore faults, barbs simply ifil le a reverse fault regardesa of slespncss or dip OTHER SYMBOLS Numbers rotor to dnnotarl listed In the appendices of the accompanying report Amatatiom include fault me, site d fault lblelenem, and pertinent refs reim indudirg Earth quake Fault Zone meps where fault has been zoned by tin Nquisl-Pnolo Earthquake Fault Zoning Act This Act requires the State Geula pint to delineate on. to encompass faults In Holocene displacement structures ox—m uty (oftshorel sepwatrg ddermg Neogene structural domains May indlo!e daconti- nul.es pelae ant '.M. er_ks Brewer Seismic Zone a Nn.. Zon. of seitri locally up to ID li wide —dreled wwlh the releasing wrap between the Imperial and San Andean faults Geologic 1'cars Beforc Fanh Reeenew DESCRIPTION Timc Pmsenl Sw nl bo! of ON LAND OFFSHORE Scale (Approc) 1losamcbt L• e CY s h bps ops Mdiempncetl F.W ala Yin HPlwumv — d.+.nnwdw.+•wn Ivow.ro r,erlss ar m eiderwp S b a h stews - r.Mrgre sol _d Na ,sYl.Ir roc—_-. wi.:� Wnbillxry bWw ?4SuT t iVT SPWkGS 'd:.Tl v �! '.Z _ PALM­ [fin (� iuINGrT . ti R!1l�L 7UNl�.• � � - CITY - FOREST we rxn: Project Site LANDMARK Plate Project No.: LP18112 Vicinity Map A-1 S%C• • � c s a . •r � rk w. T2�� T7 i t • $ }` r � r .40 .0t * -- Legend Approximate Test Pit Location LANHMARK Plate Project No.: LP18112 Site and Exploration Plan A-2 R s 1, y •m _ - y ir• !'�G �. Nnlul.d HNsunrCt's -,_ �O.i ,'..�•- � 1 CO serva(inn Service n:.alu: " 1•; e'_„ :•,ir; '; LANDMARK USDA Soil Conservation Plate Project No.: LP18112 Soil Service Map A-3 Soil Map—Riverside County, Coachella Valley Area, California Map Unit Legend Map Unit Symbol i Map UnR Name CdC Carsitas gravelly sand, 0 to 9 percent slopes IRU Rubble land Totals for Area of Interest Acres in AOI LSDa Natural Resources Web Soil Survey Conservation Service National Cooperative Soil Survey 3.5 2.8 6.3 Percent of AOI 56.0% 44.0% 100.0% 7/19/2018 Page 3 of 3 Etlei.h nrstur' - 1[ }D lq*Q[eb Cyydod 6 MI Delmm Yarv[/0[ 1T US Some Daw USM 701 B Soak: 1: 74000 Orb& LL I Datm WGW LANDMARK Plate Project No.: LP18112 Topographic Map A-4 Fault Map Notes Legend Fa.dls .e PL :. a q�� • Ems.. Project Site '�A'.'�FJ A::T' Map, r, cetr nre !:, Ce v:ec fir rv'arer-e puocoeo of :y Al y hr�;v, x•e nP 7ro urc tre �C�1 �«r��.��:r•.«•.x��,:r_rsa„ �.�r.anr�ao r.rti>c�„�a•,�,rd�r i!,o::>.,-y���,r•r.•i.:�,+yr.•�� r �: crenae z: to ft'e ceder! ,to svu:e �: oRen I-. re pati a:a+x. orne'ne r.. x mc, 6•'rn e.. of a.q o x dela p -d,^_ and ., :-._n., • �:rgz! wc{;�: �d r. l", Lne .,loumdirn comm -rd c .Cl', mep Al' csv of !ix P:t;.L,t »rJ: re:oe_t ;o —Lrec, v,d P•e:.�si�n st'a'I to me sae of C, 13 576 Feet -� P,E�OS7F.zIMTGDC:: 9U7CaI'7:�'�7 d4. .:;erode'".anM'y. FCIT G!� LANUMARK Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 Fault Map A-5 Subsidence Map Project Site Ir LANUMARK Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 - Subsidence AJ -6 Notes ... ..... . .... . .. . .T -:JT Fi �,T e I e I A r', 3 C f L -.11 w at --'W' C1 J. ca C r. c &A :c-Owt cr. 'o-. I 'P., -,,,I PAT, LANUMARK Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 - Subsidence AJ -6 Liquefaction Map IV LAN UM n a V Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 Liquefaction Zones A_7 T 7. 14 Legend ��a�,FlaCl� Project Site 9 'f"X, „i. Notes 1 ........... .... IIJ1`-,RTA7' PAU ane ;:ate arf to hr uzad r3r afore... ourp:.: r.: ciy Nap feah�rr: are m�:c•nurn. RC� cad are rA neceaar �� v—w , vo ur aary ;• v�g ooerng s'rn dmds �,e Cert, -1 Ri.vride .ra,v: no F!:r.rn, :y ;; l.ea Gc t` .n I) :'rt .t rr i�'. I:'in :;rrc. ; c('v:n :niJ I:nt,� a coc_le:e rf zz o' ary cf t'•,e data pr.:dvd and .z:crcvz n❑ 'vgal rn�p cnu ttity L -r I}'G IGiC'[f1a9�'1 CCMETad a�i1,.:nnr{t.=r.. oc.riln., pc:h.c; w, eiecpci +hsm•ncy vrl f.mccw•,:^allhr lF. r•:��r��.'oe�Slrtj of i Ian i •"rr •. '�L•9-M � �� `t.P _�P.T Pr 4"'C'�"l fl:',°rD17 R—de r-,r,tv 4Y. IT[S LAN UM n a V Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 Liquefaction Zones A_7 Flood Map �7 Project Site 5 LANDMARK Riverside County Geographic Information System (GIS) Plate Project No.: LP18112 Flood Map A-8 LEGEND SPECIAL FLOOD HAZARD AREAS SUBJECT TO INUNDATION BY THE 1% ANNUAL CHANCE FLOOD The L% annual flood (100 -year flood), also known as dw base Road, Is the flood that has a 196 &once of being equaled or a In any given year. The Special Flood Hazard Area is the area subject to flooding by the 1% annual chance flood. Areas of Special Flood Hazard Include Zones A, AE, AFI, A0, AR, A99, V, and VE The Base Flood Elevation Is the water -surface elevation or the 1% annual chance flood. ZONE A No Base Flood Elevations del ermined. ZONE AE Base Flood Elevations debe mined. ZONE AH Flood depths of 1 to 3 feet (usualy arms of pcndoq); Base Flood Geographic coordinates mfe d to the Nath Amei[an Elevations debarnMned. ZONE AO flood depths of l to 3 fee[ (usually shad flaw on sloping lerrain); average 1000-meber Universal Transverse Mesailior grid values, zone depths determined. For arm of Auvial fan flooding, velotl0es also 11N deter n fined. ZONE AR Special Fbod Hazard Area formerly pzfsd from the 1% annual dance ZONE X flood by a flood control systern that was subsequently da.e bfit!:. Zone AR ZONE D indicates that the former flood control system is being restored bD provide FIRM pond) protection from the 1% annual chance or greater flood. ZONE Aft Area to be prvtar i from 1% annual chance flood try a Federal flood ®RS areas and OPAs are normaly bcatad within or adjacent to Special Flood Hazard Areas. protection syste n under construction; no base Flood Elevations 1% annual chance floodplain bdrhdery determined. ZONE V Coastal flood zone with velocity hazard (wave action); no Base flood Elevations determined. ZONE VE Coastal flood zone with velocity hazard (vr action); Base flood CBRS and OPA boundary Elevations determined. • Referenced m the North American Vertical Dadhm of 1966 FLOODWAY AREAS IN ZONE AE The floodway Is the rdhannel of a so earn plus any adjacent fbodplaln areas that must be kept free of enoioacMrmt so that the 1% annual dunce flood can be canned wdhoA substantial increases In flood freights. 87'07'45". 32'22'30" Geographic coordinates mfe d to the Nath Amei[an OTHER FLOOD AREAS ZONE X Areas of 0.2% annual chance food; areas of 1% annual chance flood wRh 1000-meber Universal Transverse Mesailior grid values, zone average depths of less than 1 foot or with drainage areas less than 11N 1 square male; and areas protected by levees from 1% annual chance nand. 5000•fcot grid ticks: California Stabe Plane coordinate OTHER AREAS ZONE X Areas determli ed to be amide the 0.2% annual chance floodplain. ZONE D Areas In whidr flood hazards are 4xi e!$nnnea, but possible- ossibleCOASTAL FIRM pond) COASTALBARRIER RESOURCES SYSTEM (CBRS) AREAS River Mlle OTHERWISE PROTECTED AREAS (OPAs) ®RS areas and OPAs are normaly bcatad within or adjacent to Special Flood Hazard Areas. 1% annual chance floodplain bdrhdery 0.2% arcual chance Iloodplain bouday Flood" boundary Zane D bou Bary ................ CBRS and OPA boundary Bohnday dividing Special Flood Hazard Area Zones and bmxxWy dividing Sperlal Hood Flazard Arms of different Base FbW Elevations, flood depths or flood velodoes. Sia Base Flood Elevation the and value elevation In feet - (EL 967) Base Hood Elevation value where unciform within zone; elevation in fed• • Referenced m the North American Vertical Dadhm of 1966 A a Cr. section line - — — — — - - TrarsatIme 87'07'45". 32'22'30" Geographic coordinates mfe d to the Nath Amei[an Datran of 1983 (NAD 83), Western HeNsphese '76—N 1000-meber Universal Transverse Mesailior grid values, zone 11N 600000 FT 5000•fcot grid ticks: California Stabe Plane coordinate system, cone VI (F)PSZONE 0406), Lambert Conformal Conk pro)ectJon DX5510 x Ber'c' mark (see e`pdrhatlm in Nate' to Users section of this FIRM pond) •M1.5 River Mlle _ a FIELD ......__......_ W I- w Cf) < U)¢ O 0 U Q U) -j JO Ow W rn ZDU mU tL� LOG OF TEST PIT NO. T-2 SHEET 1 OF 1Uj LABORATORY } } z 0�w�Oo� ooa Lu z `� z e 2U° OTHER TESTS DESCRIPTION OF MATERIAL 1221 2.0 SAND (SP -SM): Brown, dry, loose, medium grained, medium dense, some cobbles and boulders to 1 to 3 ft 113.6 25 5 10 15 Total Depth = 14 5' Moisture and density values by Nuclear Densometer (ASTM 6938) Backfilled with excavated soil 20 25 30 DATE EXCAVATED: 6/22/18 TOTAL DEPTH: 14.5 Feet DEPTH TO WATER: N/A LOGGED BY: J. Lorenzana TYPE OF BIT: Backhoe DIAMETER: N/A SURFACE ELEVATION: HAMMER WT".: NIA DROP: N/A PROJECT NO. LP18112 LANDMARK PLATE B-2 DEFINITION OF TERMS PRIMARY nIVIAMNR RVIVIPIni R cFrr)Nr%ARV nlvtcln Alc GRAIN SIZES Sills and Clays Sand Gravel Cobbles Boulders Fine Medium Coarse Fine Coarse '. 'l .:0 10 d 3r4` 3' 12.. 1. Sands, Gravels, etc. 11 Gravels Clean gravels (less GW Well graded gravels gravel -sand mixtures, little or no fines 'A'•iriY Loose •- - Medium Dense than 59t, fines) Dense More than half of Very Dense Pood g GP Y graded gravels. or ravel -sand mixtures, little or no fines S Uff !pigGM Silly gravels, gravel -sand -silt mixtures, non -plastic fines &16 coarseon is larger thanhan No 4 2 0-4 0 sieve Gravel with fines �✓4 GC Clayey gravels, gravel -sand -Gay mixtures plastic fines Coarse grained soils More hon half of material is large [hal No 200 sieve Sands Clean sands (less ryix.S 4'i SW Well graded sands, gravelly sands, little or no fines ;,�5{,'Z than 5% fines) - More than half of SP Poorly graded sands or gravelly sands, little or no fines ., ',�., SM Silly sands sand -silt mixtures, non -plastic lines coarse fraction is smaller than Nc 4 sieve Sands with fines �l SC Clayey sands sand -clay mixtures plastic lines Silts and clays if it l 11 ML Inorganic silts, clayey sills with slight plasticity CL Inorganic days of low to medium plasticity, gravely sandy, or lean days Liquid limit is less than 50% -- - ' 'I OL Organic sills and organic days of IoN plasticity ii 1wine grained soils More than1 hail of material is smaller Silts and clays 1 I I I MH Inorganic silts, micaceous or diatomaceous silty soils, elastic sills than No, 200 sieve CH Inorganic clays of high plasticity, fat Gays Liquid limit is more than 50'/ OH Organic Gays of medium to high plasticity, organic silts Highly organic soils PT Peat and other highly organic soils GRAIN SIZES Sills and Clays Sand Gravel Cobbles Boulders Fine Medium Coarse Fine Coarse '. 'l .:0 10 d 3r4` 3' 12.. 1. Sands, Gravels, etc. 11 Blowsif . Very Loose 0-4 Loose 4-10 Medium Dense 10-30 Dense 3&50 Very Dense Over 50 US Standard Series Sieve Clear Square Openings Clays & Plastic Silts Strength Blovn t. Very Soft 0-0.25 0-2 Soft 0-25-0 5 2-4 From 05-1 0 4-9 S Uff 1.0-20 &16 Very Stiff 2 0-4 0 10-32 Hard Over 4 0 C ` Number of blows of 140 Ib. hammer falling 30 inches to drive a 2 inch O.D. (1 3/8 in. 1. D.) split spoon (ASTM D1586) Unconfined compressive strength in tons/s.f. as determined by laboratory testing or approximated by the Standard Penetration Test (ASTM D1586), Pocket Penetrometer, Torvane, or visual observation. Type of Samples: 0 Ring Sample 61 Standard Penetration Test 1 Shelby Tube ® Bulk (Bag) Sample Drilling Notes: 1. Sampling and Blow Counts Ring Sampler- Number of blows perfoot of a 140 lb- hammer falling 30 inches. Standard Penetration Test- Number of blows perfoot. Shelby Tube - Three (3) inch nominal diameter tube hydraulically pushed 2, P. P. = Pocket Penetrometer (tons/s.f.). 3. NR =No recovery. 4. GVVT -T = Ground Water Table observed QR specified time. LANOMARK Plate Project No. LP18112 Key to Logs B-3 I I � I I I I , I I II I � I � 0 y CID y i I ` i N a f ' 30 20 -T-1 ® 0.7 II, f I I€ 1j 10 0 1000.000 100.000 10.000 0010 Particle Size (mm) LANDMARK Plate Project No.: LP13112 Grain Size Analysis C-1 SIEVE ANALYSIS Cobbl es and Boulders Gravel Sand Silt Goarse Fine Coarse Medium Fine and Clay I I � I I I I , I I II I � I � 0 y CID y i I ` i N a f ' 30 20 -T-1 ® 0.7 II, f I I€ 1j 10 0 1000.000 100.000 10.000 0010 Particle Size (mm) LANDMARK Plate Project No.: LP13112 Grain Size Analysis C-1 SIEVE ANALYSIS Cobbl LANDMARK CONSULTANTS, INC. CLIENT: Coronel Enterprises, Inc. PROJECT: 77137 Casa del Sol — La Quinta, CA JOB No.: LP18112 DATE: 07/02/18 CHEMICAL ANALYSIS --------------------------------------------------------- Boring: T-1 Caltrans Sample Depth, ft: 0-3 Method pH: 8.5 643 Electrical Conductivity (mmhos): -- 424 Resistivity (ohm -cm): 1,600 643 Chloride (CI), ppm: 110 422 Sulfate (SO4), ppm: 53 417 General Guidelines for Soil Corrosivit Material Chemical Amount in Degree of Affected Agent Soil (ppm) Corrosivity Concrete Soluble 0-1,000 Low Sulfates 1,000 - 2,000 Moderate 2,000 - 20,000 Severe > 20.000 Very Severe Normal Soluble 0-200 Low Grade Chlorides 200-700 Moderate Steel 700-1,500 Severe > 1,500 Very Severe Normal Resistivity 1 - 1,000 Very Severe Grade 1,000 - 2,000 Severe Steel 2,000 - 10,000 Moderate > 10,000 Low _1111: i► Project No.: LP18112 Selected Chemical Test Results Plate C-2 Client: Coronel Enterprises, Inc. Soil Description: Sand (SP -SM) Project: 77137 Casa Del Sol — La Quinta, CA Sample Location: T-1 @ 0-3 ft. Project No.: LP18112 Test Method: ASTM D-1157 A Date: 7/2/2018 Maximum Dry Density (pcf): 134.9 Lab. No.: N/A Optimum Moisture Content (%): 6.5 140 130 110 100 0 LANOMARK Project No.: LP18112 5 10 15 20 25 Moisture Content (°/) Moisture Density Relationship 30 I 1 Plate C-3 REFERENCES American Concrete Institute (ACI), 2013, ACI Manual of Concrete Practice 302.1 R-04 American Society of Civil Engineers (ASCE), 2010, Minimum Design Loads for Buildings and Other Structures: ASCE Standard 7-10. California Building Standards Commission, 2017, 2016 California Building Code. California Code of Regulations, Title 24, Part 2, Vol. 2 of 2. Caltrans, 2012, Highway Design Manual_ California Division of Mines and Geology (CDMG), 1996, California Fault Parameters: available at http:l/N4iyw.ei)nsrv.ca.g«y/dmg/shezp!flLindex.htmi. California Geological Survey (CGS), 2008, Guidelines for Evaluating and Mitigating Seismic Hazards in California, Special Publication 1 17A, 98p. California Geological Survey (CGS), 2018, Fault Activity Map of California h ttp://www.quake.ca. govlgm aps/FA NI/fau I Cactiy_i.tN7 map. htm 19. California Geological Survey (CGS), 2018, Alquist-Priolo Earthquake Fault Zone Maps. http:llmaps.canseryation.ca, L,,ovlcg sl in form ati on wareiiouseli ndex.htm i?map=rem atorymal2s Cetin, K. O., Seed, R. B., Der Kiureghian, A., Tokimatsu, K., Harder, L. F., Jr., Kayen, R. E., and Moss, R. E. S., 2004, Standard penetration test -based probabilistic and deterministic assessment of seismic soil liquefaction potential: ASCE JGGE, Vol., 130, No. 12, p. 1314-1340. Geologismiki, 2017, CLiq Computer Program, www.geologismiki.gr Ishihara, K. (1980, Stability of natural deposits during earthquakes, Proc. 1 I"' Int. Conf. On Soil Mech. And Found. Engrg., Vol. 1, A. A. Balkema, Rotterdam, The Netherlands, 321-376. Jones, A. L., 2003, An Analytical Model and Application for Ground Surface Effects from Liquefaction, PhD. Dissertation, University of Washington, 362 p. McCrink, T. P., Pridmore, C. L., Tinsley, J. C., Sickler, R. R., Brandenberg, S. J., and Stewart, J. P., 2011, Liquefaction and Other Ground Failures in Imperial County, California, from the April 4, 2010, EI Mayor—Cucapah Earthquake, CGS Special Report 220, USGS Open File Report 2011-1071, 84 p. Post -Tensioning Institute (PTI), 2007a, Standard Requirements for Analysis of Shallow Concrete Foundations on Expansive Soils (3 d Edition). Post -Tensioning Institute (PTI), 2007b, Standard Requirements for Design of Shallow Post -Tensioned Concrete Foundations on Expansive Soils (2nd Edition). Robertson, P. K., 2014, Seismic liquefaction CPT -based methods: SERI lst Workshop on Geotechnical Earthquake Engineering — Liquefaction Evaluation, Mapping, Simulation and Mitigation. UC San Diego Campus, 10/12/2014. Robertson, P. K. and Wride, C. E., 1997, Cyclic Liquefaction and its Evaluation based on the SPT and CPT, Proceeding of the NCEER Workshop on Evaluation of Liquefaction Resistance of Soils, NCEER Technical Report 97-0022, p. 41-88. Rymer, M.J., Treiman, J.A., Kendrick, K.J., Lienkaemper, J.J., Weldon, R.J., Bilham, R., Wei, M., Fielding, E.J., Hernandez, J.L., Olson, B.P.E., Irvine, P.J., Knepprath, N., Sickler, R.R., Tong, .X., and Siem, M.E., 2011, Triggered surface slips in southern California associated with the 2010 El Mayor-Cucapah, Baja California, Mexico, earthquake: U.S. Geological Survey Open -File Report 2010-1333 and California Geological Survey Special Report 221, 62 p., available at http://pubs.usgs.gov/of/ 2010/1333/. U.S. Geological Survey (USGS), 1990, The San Andreas Fault System, California, Professional Paper 1515. U.S. Geological Survey (USGS), 2017, US Seismic Design Maps Web Application, available at http:/.geohazards.usgs.gciy/designmJpslus/.lilpIicat ion. PhP Wire Reinforcement Institute (WRI/CRSI), 2003, Design of Slab -on -Ground Foundations, Tech Facts TF 700-R-03, 23 p. Youd, T. L., 2005, Liquefaction -induced flow, lateral spread, and ground oscillation, GSA Abstracts with Programs, Vol. 37, No. 7, p. 252. Youd, T. L. and Garris, C. T., 1995, Liquefaction induced ground surface disruption: ASCE Geotechnical Journal, Vol. 121, No. 11.