ITEM 5 EXHIBITS A-H - Laserfiche WebLink

BLACK AVENUE RESIDENTIAL DEVELOPMENT 648-26-1 Page 2 building foundations, flatwork, and pavements, and preparation of this preliminary report. Brief descriptions of our exploration and laboratory programs are presented below. 1.3 EXPLORATION PROGRAM Field exploration consisted of three hand auger (HA) borings and five Cone Penetration Tests (CPTs) advanced on May 2, 2022. The HA borings were advanced to a depth of approximately 2 to 4 feet. The CPTs were advance to depths of approximately 37 to 43 feet before refusal. The CPTs were backfilled with cement grout in accordance with local requirements. The approximate locations of our explorations are shown on the Site Plan, Figure 2. Details regarding our field program are included in Appendix A. 1.4 LABORATORY TESTING PROGRAM In addition to visual classification of samples, the laboratory program focused on obtaining data for foundation design and seismic ground deformation estimates. Testing included moisture contents, washed sieve analyses, and Plasticity Index tests. Details regarding our laboratory program are included in Appendix B. 1.5 CORROSION EVALUATION Two samples from our borings from depths from 2 to 4 feet were tested for saturated resistivity, pH, and soluble sulfates and chlorides. JDH Corrosion Consultants prepared a brief corrosion evaluation based on the laboratory data, which is attached to this report in Appendix C. 1.6 ENVIRONMENTAL SERVICES Cornerstone Earth Group also provided environmental services for this project, including Phase 1 and 2 site assessments; environmental findings and conclusions are provided under separate covers. SECTION 2: REGIONAL SETTING 2.1 REGIONAL SEISMICITY While seismologists cannot predict earthquake events, geologists from the U.S. Geological Survey have recently updated (in 2015) earlier estimates from their 2014 Uniform California Earthquake Rupture Forecast (Version 3; UCERF3) publication. The estimated probability of one or more magnitude 6.7 earthquakes (the size of the destructive 1994 Northridge earthquake) expected to occur somewhere in the San Francisco Bay Area has been revised (increased) to 72 percent for the period 2014 to 2043 (Aagaard et al., 2016). The faults in the region with the highest estimated probability of generating damaging earthquakes between 2014 and 2043 are the Hayward (33%), Calaveras (26%), and San Andreas Faults (22%). In this 30-year period, the probability of an earthquake of magnitude 6.7 or larger occurring is 22 percent along the San Andreas Fault and 33 percent for the Hayward Fault. In addition to visual classification of samples, the laboratory program focused on obtaining data In addition to visual classification of samples, the laboratory program focused on obtaining data for foundation design and seismic ground deformation estimatesfor foundation design and seismic ground deformation estimates. Testing included moisture . Testing included moisture Plasticity Index tests. Details regarding our laboratory Plasticity Index tests. Details regarding our laboratory samples from our borings from depths from samples from our borings from depths from 2 2 to to 4 4 feet were testedfeet were tested pH, and soluble sulfates and chlorides. JDH Corrosion Consultants prepared a brief corrosion pH, and soluble sulfates and chlorides. JDH Corrosion Consultants prepared a brief corrosion evaluation based on the laboratory data, which is attached to this report in Appendix C.evaluation based on the laboratory data, which is attached to this report in Appendix C. ENVIRONMENTAL SERVICESENVIRONMENTAL SERVICES Cornerstone Earth Group also provided environmental services for this project, including Phase Cornerstone Earth Group also provided environmental services for this project, including Phase 1 and 2 site assessments; environmental findings and conclusions are provided under separate 1 and 2 site assessments; environmental findings and conclusions are provided under separate SECTION 2: REGIONAL SETTINGSECTION 2: REGIONAL SETTING AL SEISMICITYAL SEISMICITY