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FORT MASON AQUATIC PARK EXISTING F-MARKET LINE PROPOSED PROJECT ALIGNMENT Elev. y 0 Ft. Elev. y 95 Ft. Elev. y 10 Ft. Elev. y 10 Ft. Elev. y 12 Ft. y Elev. y 15 Ft. Elev. 7 Ft. LEGEND Project Study Area Zones of Required Investigation Liquefaction: Existing F-Market Line Stop Areas where historic occurrence of liquefaction, or Existing F-Market Line local geological, geotechnical and groundwater N conditions indicate a potential for permanent ground Proposed Fort Mason Extension displacement such that mitigation as defined in Public 0 0.125 0.25 Above ground Resources Code Section 2693(c) would be required. Earthquake-induced Landslides Underground Scale in Miles Areas where previous occurrence of landslide movement, SEISMIC HAZARD ZONES Proposed Fort Mason Extension Stop or local topographic, geological, geotechnical and SEISMIC HAZARD ZONES subsurface water conditions indicate a potential for HistoricEnvironmental Streetcar ExtensionImpact Statement EIS permanent ground displacement such that mitigation as July 2008 Historic Streetcar Extension San Francisco, California Source: CCSF, 2000 defined in Public Resources Code Section 2693(c) would 28067144 San Francisco, California be required. FIGUREFIGURE 3.11-2 2 7/10/08 vsa/hk ..T:\28067144 Historic Streetcar EIS\Tech Report 2008\F2_seismic hazard.ai AFFECTED ENVIRONMENT topography within the study area, stormwater would generally drain in a northwesterly direction towards the San Francisco Bay, except on the eastern slope of the tunnel. Stormwater drainage in the area is captured by San Francisco’s combined sewer system and treated at the Southeast Treatment Plant prior to discharge (SFPUC 2010). Soils. Soils mapped by Natural Resources Conservation Service (NRCS) in the study area fall under three classifications: Urban Land; Urban land-Orthents - cut and fill complex (5 to 75 percent slopes); and Urban land-Orthents - reclaimed complex (0 to 2 percent slopes). These classifications indicate that the soils present in the study area are highly disturbed and have little agricultural viability. Mineral Resources. Mineral resources include aggregate materials (such as sandstone, quarts, etc.) or petroleum resources. In 1987, the California Division of Mines and Geology (CDMG) published a comprehensive mineral land classification for aggregate materials in the San Francisco-Monterey Bay Area (Stinson et al., 1987). The study area is classified as an area where there are no significant mineral deposits present and where little likelihood exists for their presence (MRZ-1)1. Faults and Seismicity. The project area is located in a region of high seismic activity with numerous active and potentially active faults2 (Figure 3.11-2). The project area is influenced by the faults of the San Andreas system including San Gregorio, San Andreas, Hayward, Rodgers Creek, Concord-Green Valley, Calaveras, and Greenville Faults. Major earthquakes have affected the region in the past and can be expected to occur again in the near future on one of the principal active faults in the San Andreas fault System. Table 3.11-1 lists the location of regionally active faults significant to the project area due to proximity, activity status, and Maximum Credible Earthquake (MCE). The MCE is an 3 estimated moment magnitude (Mw) for the largest earthquake capable of occurring on a fault. TABLE 3.11-1: MAJOR FAULTS IN MUNI F-LINE EXTENSION VICINITY Minimum Maximum Probability of Horizontal Moment M 6.7 or Higher in Distance to F-Line Fault Length Magnitude the Next 30 Years Fault Name Site (miles) (miles) (MW) (percent) San Andreas (North Coast 9.5 280 7.9 21 Segment) San Gregorio 15 78 7.3 6 Hayward 14 62 6.9 31 Rodgers Creek 24 38 7.0 31 Concord-Green Valley 30 40 6.9 3 Greenville-Marsh Creek 31 43 6.9 3 1 MZ-1 is a mineral classification given by CDMG. See the Regulatory Setting of this section for a full list of classifications. 2 An active fault is defined by the CGS as a fault that has had surface displacement within Holocene time (approximately the last 11,000 years). 3 Earthquake magnitudes are also measured by their moment magnitude (Mw), which is related to the physical characteristics of a fault, including the rigidity of the rock, the size of fault rupture, and the movement or displacement across a fault. 160 Geology, Soils and Seismicity The individual faults that present the greatest seismic risk to the project study area are the Hayward and the San Andreas faults. The San Andreas fault is located approximately 9 miles to the southwest of the site and is the major tectonic boundary between the Pacific and North American plates. This portion of the San Andreas fault also marks the boundary with the less active San Francisco Bay block described by Olsen et al. (1994). The San Francisco Bay block is an area of low to moderate rates of seismicity which is largely un-dissected by Holocene (last 11,000 years) active faults. The Hayward fault, located approximately 14 miles to the east, is another major active tectonic feature in the Bay Area, and separates the Bay block from the East Bay hills. The 2007 Working Group on California Earthquake Probabilities estimates that the Bay Area has a 63 percent chance of experiencing one or more earthquakes of M 6.7 or higher over the next 30 years (Working Group on California Earthquake Probabilities 2008). Significant Faults. The following paragraphs briefly describe each of the major faults, from west to east (listed in Table 3.11-1 and shown on Figure 3.11-3). Fault data were obtained from Bortugno et al. (1991) and the Working Group on California Earthquake Probabilities (Working Group on California Earthquake Probabilities 2008). San Gregorio Fault. The San Gregorio fault is a major Holocene active fault that lies west of the San Andreas fault. The fault is approximately 78 miles long, extending from the Big Sur area northward to the area offshore of Bolinas Bay. Most of the fault lies offshore. However, in several areas, the fault lies onshore and has been actively investigated (Simpson et al. 1992). The fault has an estimated Quaternary slip rate of 5 mm/yr. Paleoseismic estimates of earthquake recurrence intervals on the fault range from 350 to 680 years based on offset archeological remains at Seal Cove (Simpson et al. 1992). The San Gregorio fault is located approximately 15 miles from the site and the maximum earthquake magnitude for the fault is estimated to be approximately Mw 7.3. San Andreas Fault. The San Andreas fault is the largest active fault in California, and extends from the Gulf of California on the south end to approximately 750 miles to Cape Mendocino on the north end. It was the source of the 1906 Mw 7.9 San Francisco earthquake (Wallace 1990), which ruptured approximately 280 miles of the fault from San Juan Batista to Shelter Cove. The fault is about 9.5 miles southwest of the site at its closest approach. The San Andreas fault can be divided into a number of segments, based on differences in geomorphology, geometry, paleo seismic chronology, seismicity, and historic displacements. In the Bay Area, these segments include the southern Santa Cruz Mountains, possible source of the 1989 Mw 7.0 Loma Prieta earthquake; the Peninsula segment; and the North Coast segment. The North Coast Segment runs from Shelter Cove in the north, to south of San Francisco. These segments have been assigned maximum earthquakes of Mw 7, Mw 7.1, and Mw 7.9, respectively. Hayward Fault. The Hayward fault is about 62 miles long and has been divided into two fault segments: a longer southern segment, and a shorter northern segment. The fault demonstrates systematic right-lateral creep along its entire length (Lienkaemper et al. 1991). This structure is considered to be the most likely source of the next major earthquake in the San Francisco Bay area (Working Group on California Earthquake Probabilities, 2008), and is located approximately 14 miles 161 The tunnel was used by public railroad systems and by the United States military, but for a number of years the tunnel has been closed and currently is not operational. A 1998 Federal Highway Administration (FHWA) inspection report indicates, "The tunnel is extensively deteriorated and practically non-functional." There are significant problems with water infiltration in the eastern half of the tunnel, spalling and section loss of the concrete liner, various small cracks and a 425-foot long crack in the arch of the tunnel lining in the west end. In addition, voids behind the tunnel lining at some locations are also present. Based on a literature review and a visit to the tunnel, we have identified the following geologic and geotechnical issues that could affect the long-term stability of the tunnel: • Water infiltration • Strong ground shaking during earthquakes • Earthquake-induced liquefaction, lateral spreading, and dynamic compaction in the western portion underlain by sands • Landsliding near east portal • Possible stress concentrations on the tunnel liner due to contrasting soil and rock types along its length Based on the results of our field geological reconnaissance and geotechnical investigation, existing geologic cross section along the tunnel alignment is shown in Figure 3. It should be noted that our interpreted geology at the site improved significantly on the previous geologic interpretations. Qaf - Artificial fill (Historical) Figure 3: Geologic cross section. Explanation of geologic units: Qaf Artificial fill Qd - Dune sand (Holocene) (Historical);Qod - Older dune Qd sand (Holocene) Dune sand (Holocene); Qod Older dune sand (Holocene); Qsr Slope debris and ravineQsr - Slopefill debris(Holocene); and ravine fill (Holocene) KJss Franciscan sandstone (Cretaceous-Jurassic); KJsh Franciscan shale KJss - Franciscan sandstone (Cretaceous-Jurassic) KJsh - Franciscan(Cretaceous-Jurassic); shale (Cretaceous-Jurassic) KJss (a) Sandstone within KJsh (Cretaceous-Jurassic) KJss (a) - Sandstone within KJsh (Cretaceous-Jurassic) OBJECTIVES GEOLOGIC CROSS SECTION Source: URS Environmental Impact Statement The primary objectives of our study to investigate and refine tunnel rehabilitationHistoric options Streetcar Extensionand to develop project feasibility construction estimates for the preferred options.

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