Microsoft Word - 1-Introduction4. Environmental Setting, Impacts,
Standard Conditions of Approval, and Mitigation Measures
ABSMC Summit Campus Seismic Upgrade and 4.8-1 ESA / 207376 Master
Plan Project Draft EIR December 2009
4.8 Geology, Soils, and Geohazards This section describes geologic
and seismic conditions in the project vicinity to provide relevant
background information of the physical characteristics of the
project site with respect to soils and potential geologic hazards.
The following information is compiled from geologic maps and
reports available from the City of Oakland, the California
Geological Survey (CGS; formerly California Division of Mines and
Geology), the ABAG, two geotechnical reports prepared by Geomatrix
in 2008, and a third geotechnical report prepared by AMEC Geomatrix
in 2009.
This section identifies any potentially significant geologic
impacts and, if necessary, appropriate mitigation measures or
standard conditions of approval. Pursuant to the City’s amendment
to the Oakland General Plan (City of Oakland, 2005), as well as
Section 15358(b) of the CEQA Guidelines, mitigation measures are
proposed only to address physical impacts that may result from the
project.
4.8.1 Environmental Setting The project site is situated within the
Coast Ranges geomorphic province of California. The Coast Ranges is
the largest of the state’s geomorphic provinces extending
approximately 400 miles from the Klamath Mountains (near northern
Humboldt County) to the Santa Ynez River in Santa Barbara County.
The province lies between the Pacific Ocean and the Great Valley
(Sacramento and San Joaquin valleys) provinces and is characterized
by a series of northwest trending mountain ridges and valleys,
running generally parallel to the San Andreas Fault zone. These
mountain ridges and valleys have been formed by tectonic forces
that compressed ancient sedimentary deposits over the course of
millions of years.
San Francisco Bay is located in a broad depression in the
Franciscan bedrock resulting from an east-west expansion between
the San Andreas and the Hayward fault systems. The bedrock surface
can be found at elevations of 200 to 2,000 feet below mean sea
level across the Bay Area. Sedimentary deposits that overlie the
Franciscan bedrock originated from millions of years of erosion,
deposition, and changes in sea level. Geologists categorize these
sedimentary deposits into geologic formations based on the period
of deposition and material type, as described below for the San
Francisco Bay region.
• The Alameda Formation is the deepest and oldest of these
sedimentary deposits and consists of a mixture of clay, silt, sand,
gravel, and some shells with predominantly silt and clay sediments
surrounding discontinuous layers of sand and gravel;
• Overlying the Alameda Formation is the San Antonio Formation,
which consists of sandy clays, gravelly clays, clayey sands and
gravels with interbedded silty clay deposits.
• Younger alluvial deposits once referred to as the Temescal
Formation are deposited on top of the San Antonio and consist of
sandy clays, clayey sands, sands and gravels. The source material
for these alluvial deposits comes from the Berkeley Hills.
4. Environmental Setting, Impacts, Standard Conditions of Approval
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ABSMC Summit Campus Seismic Upgrade and 4.8-2 ESA / 207376 Master
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The geotechnical report conducted for the project site describe the
subsurface conditions of the site as thick alluvial sediments
(approximately 325 feet thick) overlying Franciscan Complex
sedimentary bedrock units (Geomatrix, 2008). The alluvial materials
consist primarily of stiff clays interbedded with dense silty sands
and gravel lenses (Geomatrix, 2008).
Seismicity Seismic hazards include those hazards that could
reasonably be expected to occur in the area during a major
earthquake on any of the active faults in the region. Some hazards
can be more severe than others, depending on the location,
underlying materials, and level of ground shaking. The project
site, like the entire Bay Area, lies within an area that contains
many active and potentially active faults and is considered to be
an area of high seismic activity.1 The USGS Working Group on
California Earthquake Probabilities evaluated the probability of
one or more earthquakes of Richter magnitude 6.7 or higher
occurring in the San Francisco Bay Area within the next 30 years
(USGS, 2008).2 The result of the evaluation indicated a 63 percent
likelihood that such an earthquake event will occur in the Bay Area
between 2007 and 2037 (USGS, 2008).
Ground movement during an earthquake can vary depending on the
overall magnitude, distance to the fault, focus of earthquake
energy, and type of geologic material. The composition of
underlying soils, even those relatively distant from faults, can
intensify ground shaking. For this reason, earthquake intensities
are also measured in terms of their observed effects at a given
locality. The Modified Mercalli (MM) intensity scale (Table 4.8-1)
is commonly used to measure earthquake damage due to ground
shaking. The MM values for intensity range from I (earthquake not
felt) to XII (damage nearly total), and intensities ranging from IV
to X can cause moderate to significant structural damage.3 The
intensities of an earthquake will vary over the region of a fault
and generally decrease with distance from the epicenter of the
earthquake.
According to the Association of Bay Area Governments (ABAG) Shaking
Intensity Maps and Information, the project site is located in an
area subject to “moderate” ground shaking (Modified Mercalli
Intensity VI) from earthquakes along the entire San Andreas
(similar to the 1906 Earthquake), and “strong” ground shaking
(Modified Mercalli Intensity VIII) from the Northern and Southern
segments of the Hayward Fault (ABAG, 2009c).
1 An “active” fault is defined by the State of California as a
fault that has had surface displacement within Holocene
time (approximately the last 11,000 years). A “potentially active”
fault is defined as a fault that has shown evidence of surface
displacement during the Quaternary (last 1.6 million years), unless
direct geologic evidence demonstrates inactivity for all of the
Holocene or longer. This definition does not, of course, mean that
faults lacking evidence of surface displacement are necessarily
inactive. “Sufficiently active” is also used to describe a fault if
there is some evidence that Holocene displacement occurred on one
or more of its segments or branches (Hart, 1997).
2 Richter magnitude is a measure of the size of an earthquake as
recorded by a seismograph. Richter magnitudes vary logarithmically,
with each whole number step representing a ten-fold increase in the
amplitude of the recorded seismic waves. 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 movement or displacement
across a fault.
3 The damage level represents the estimated overall damage that
will occur for various MM intensity levels. Damage, however, is not
uniform, as the age, material, type, method of construction, size,
and shape of a building all affect its performance.
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and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-3 ESA / 207376 Master
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TABLE 4.8-1 MODIFIED MERCALLI INTENSITY SCALE
Intensity Value Intensity Description
(% ga)
I Not felt except by a very few persons under especially favorable
circumstances. < 0. 17 g
II Felt only by a few persons at rest, especially on upper floors
on buildings. Delicately suspended objects may swing.
0.17-1.4 g
III Felt noticeably indoors, especially on upper floors of
buildings, but many people do not recognize it as an earthquake.
Standing motor cars may rock slightly, vibration similar to a
passing truck. Duration estimated.
0.17-1.4 g
IV During the day felt indoors by many, outdoors by few. At night,
some awakened. Dishes, windows, doors disturbed; walls make
cracking sound. Sensation like heavy truck striking building.
Standing motor cars rocked noticeably.
1.4–3.9g
V Felt by nearly everyone, many awakened. Some dishes and windows
broken; a few instances of cracked plaster; unstable objects
overturned. Disturbances of trees, poles may be noticed. Pendulum
clocks may stop.
3.5 – 9.2 g
VI Felt by all, many frightened and run outdoors. Some heavy
furniture moved; and fallen plaster or damaged chimneys. Damage
slight.
9.2 – 18 g
VII Everybody runs outdoors. Damage negligible in buildings of good
design and construction; slight to moderate in well-built ordinary
structures; considerable in poorly built or badly designed
structures; some chimneys broken. Noticed by persons driving motor
cars.
18 – 34 g
VIII Damage slight in specially designed structures; considerable
in ordinary substantial buildings, with partial collapse; great in
poorly built structures. Panel walls thrown out of frame
structures. Fall of chimneys, factory stacks, columns, monuments,
walls. Heavy furniture overturned. Sand and mud ejected in small
amounts. Changes in well water. Persons driving motor cars
disturbed.
34 – 65 g
IX Damage considerable in specially designed structures;
well-designed frame structures thrown out of plumb; great in
substantial buildings, with partial collapse. Buildings shifted off
foundations. Ground cracked conspicuously. Underground pipes
broken.
65 – 124 g
X Some well-built wooden structures destroyed; most masonry and
frame structures destroyed with foundations; ground badly cracked.
Rails bent. Landslides considerable from riverbanks and steep
slopes. Shifted sand and mud. Water splashed (slopped) over
banks.
> 124 g
XI Few, if any, (masonry) structures remain standing. Bridges
destroyed. Broad fissures in ground. Underground pipelines
completely out of service. Earth slumps and land slips in soft
ground. Rails bent greatly.
> 1.24 g
XII Damage total. Practically all works of construction are damaged
greatly or destroyed. Waves seen on ground surface. Lines of sight
and level are distorted. Objects are thrown upward into the
air.
> 1.24 g
a g (gravity) = 980 centimeters per second squared. 1.0 g of
acceleration is a rate of increase in speed equivalent to a car
traveling 328
feet from rest in 4.5 seconds. SOURCE: (ABAG, 2003)
4. Environmental Setting, Impacts, Standard Conditions of Approval
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ABSMC Summit Campus Seismic Upgrade and 4.8-4 ESA / 207376 Master
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The project area is not in an Alquist-Priolo Earthquake Fault
Zone4, and no known active fault exists on or in the project area
boundaries. The closest active fault is the Hayward-Rodgers Creek
fault approximately 3 miles east of the project area (Jennings,
1994). Like the entire Bay Area, the project site is subject to
ground shaking in the event of an earthquake on the regional
faults.
Regional Faults The San Andreas, Hayward-Rodgers Creek, and
Calaveras faults pose the greatest threat of significant damage in
the Bay Area according to the USGS Working Group (USGS, 2008).
These three faults exhibit strike-slip orientation and have
experienced movement within the last 150 years (see Table 4.8-2).5
Other principal faults capable of producing significant ground
shaking in the Bay Area include the San Gregorio, Concord-Green
Valley and the Marsh Creek-Greenville faults. These faults are all
considered active. Many other potentially active and inactive
faults are also located throughout the Bay Area. Considerable
seismic events can occur on faults with a long period of
inactivity, although it is generally considered less likely.
Occasionally, faults classified as inactive can exhibit secondary
movement during a major event on another active fault.
TABLE 4.8-2 ACTIVE FAULTS IN THE PROJECT SITE VICINITY
Fault
M 6.8, 1868 7.3
M 5.6–M 6.4, 1861 6.9
M 6.2, 1911, 1984
Concord- Green Valley 18 miles east Historic (1955) Active Historic
active creep 6.7
San Andreas 15 miles west Historic (1906; 1989 ruptures)
Active
M 7.1, 1989
M 7.0, 1838
Many <M 6
a See footnote 1. b Richter magnitude (M) and year for recent
and/or large events. The Richter magnitude scale reflects the
maximum amplitude of a
particular type of seismic wave. c Moment Magnitude (Mw) is related
to the physical size of a fault rupture and movement across a
fault. Moment magnitude provides a
physically meaningful measure of the size of a faulting event (CGS,
2002). The Maximum Moment Magnitude Earthquake, derived from the
joint CGS/USGS Probabilistic Seismic Hazard Assessment for the
State of California, 1996 (Peterson, 1996).
SOURCES: (1) Hart, 1997; (2) Jennings, 1994; (3) Peterson, 1996;
(4) USGS, 2003; (5) Geomatrix, 2008.
4 An Alquist-Priolo Earthquake Fault Zone is an established
regulatory zone around the surface traces of active
faults. Local agencies must regulate most development projects
within the zones. 5 A strike-slip fault is a fault in which
movement is horizontal, parallel to the strike of the fault
plane.
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Hayward Fault The Hayward Fault Zone is the southern extension of a
fracture zone that includes the Rodgers Creek fault (north of San
Pablo Bay), the Healdsburg fault (Sonoma County), and the Maacama
fault (Mendocino County). The Hayward fault trends to the northwest
within the East Bay, extending from San Pablo Bay in Richmond, 60
miles south to east San José. The Hayward fault in San José
converges with the Calaveras fault, a similar type fault that
extends north to Suisun Bay. The Hayward fault is designated by the
Alquist-Priolo Earthquake Fault Zoning Act as an active
fault.
A characteristic feature of the Hayward fault is its well-expressed
and relatively consistent fault creep. Although large earthquakes
on the Hayward fault have been rare since 1868, slow fault creep
has continued to occur and has caused measurable offset. Fault
creep on the East Bay segment of the Hayward fault is estimated at
9 millimeters per year (Peterson, 1996). However, a large
earthquake could occur on the Hayward fault with an estimated
moment magnitude (Mw) of about Mw 7.3. The USGS Working Group on
California Earthquake Probabilities includes the Hayward–Rodgers
Creek Fault Systems in the list of those faults that have the
highest probability of generating earthquakes of magnitude (M) 6.7
or greater in the Bay Area (USGS, 2008).
Calaveras Fault The Calaveras fault is a major right-lateral
strike-slip fault that has been active during the last 11,000
years. The Calaveras fault is located in the eastern San Francisco
Bay region and generally trends along the eastern side of the East
Bay Hills, west of San Ramon Valley, and extends into the western
Diablo Range, and eventually joins the San Andreas Fault Zone south
of Hollister. The northern extent of the fault zone is somewhat
conjectural and could be linked with the Concord fault.
The Calaveras fault has been the source of numerous moderate
magnitude earthquakes, and the probability of a large earthquake
(greater than M6.7) is much lower than on the San Andreas or
Hayward faults (USGS, 2008). However, this fault is considered
capable of generating earthquakes with Mw 6.9.
Concord-Green Valley The Concord and Green Valley faults are part
of the larger San Andreas Fault system. The Concord fault extends
from the northwestern slope of Mt. Diablo north to Suisun Bay,
where the Green Valley fault is generally thought to be connected
to the Concord fault and continues north to Wooden Valley in Napa
County. Several site-specific studies on these faults have been
conducted in compliance with the Alquist-Priolo Earthquake Fault
Zoning Act, and they report the most recent displacement on these
faults between 2,600 and 2,700 years ago in the late
Holocene.
San Andreas Fault The San Andreas Fault Zone is a major structural
feature that forms at the boundary between the North American and
Pacific tectonic plates, extending from the Salton Sea in Southern
California near the border with Mexico to north of Point Arena,
where the fault trace extends out into the Pacific Ocean. The main
trace of the San Andreas fault runs through the Bay Area and trends
northwest through the Santa Cruz Mountains along the eastern side
of the San Francisco
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Peninsula. As the principal strike-slip boundary between the
Pacific plate to the west and the North American plate to the east,
the San Andreas is often a highly visible topographic feature, such
as between Pacifica and San Mateo, where Crystal Springs Reservoir
and San Andreas Lake clearly mark the rupture zone.
Seismic Hazards
Ground Shaking Strong ground shaking from a major earthquake could
affect the project site during the next 30 years. An earthquake on
any one of the active faults (listed in Table 4.8-2) could
potentially produce a range of ground shaking intensities at the
project site. Ground shaking may affect areas hundreds of miles
distant from the earthquake’s epicenter. Historic earthquakes have
caused strong ground shaking and damage in the San Francisco Bay
Area, the most recent being the Loma Prieta earthquake (moment
magnitude 6.9) in October 1989. The epicenter was approximately 50
miles south of the project site, and the earthquake caused very
strong ground shaking for about 20 seconds and resulted in varying
degrees of structural damage as far as 50 miles away. This event
produced a moderate (Modified Mercalli VI) shaking intensity in the
project area (ABAG, 2009a). The 1906 San Francisco earthquake, with
an estimated moment magnitude of 7.9, produced a strong (Modified
Mercalli VII) shaking intensity in the project area (ABAG,
2009b).
The common way to describe ground motion during an earthquake is
the duration of the shaking. However, a common measure of ground
motion is also the peak ground acceleration (PGA). The PGA for a
given component of motion is the largest value of horizontal
acceleration obtained from a seismograph. PGA is expressed as the
percentage of the equivalent acceleration of gravity (g), which is
approximately 980 centimeters per second squared. (In terms of
automobile acceleration, one “g” of acceleration is a rate of
increase in speed equivalent to a car accelerating from a
standstill to 60 mph in less than 3 seconds.) For comparison
purposes, the maximum peak acceleration value recorded during the
Loma Prieta earthquake was in the vicinity of the epicenter, near
Santa Cruz, at 0.64 g. The lowest values recorded were 0.06 g in
the bedrock on Yerba Buena Island.
An earthquake on the Hayward fault would likely produce more severe
ground shaking than was observed during the Loma Prieta earthquake
if the epicenter of the earthquake were closer in vicinity to the
project site, and along the Hayward fault. Probabilistic seismic
hazard maps indicate that peak ground acceleration in the project
region could reach or exceed 0.65 g (CGS, 2003).
Surface Fault Rupture Seismically induced ground rupture is defined
as the physical displacement of surface deposits in response to an
earthquake’s seismic waves. The magnitude, sense, and nature of
fault rupture can vary for different faults or even along different
strands of the same fault. Ground rupture is considered more likely
along active faults (see Table 4.8-2).
The project site is not within an Alquist-Priolo Fault Rupture
Hazard Zone, as designated through the Alquist-Priolo Earthquake
Fault Zoning Act, and no mapped active faults are known to
pass
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through the immediate project region. Therefore, the risk of ground
rupture at the site is low and is not discussed further in this
analysis.
Liquefaction Liquefaction is a transformation of soil from a solid
to a liquefied state during which saturated soil temporarily loses
strength resulting from the buildup of excess pore water pressure,
especially during earthquake-induced cyclic loading. Soils
susceptible to liquefaction include saturated loose to medium dense
sands and gravels, low-plasticity silts, and some low-plasticity
clay deposits. Liquefaction and associated failures could damage
foundations, disrupt utility service, and can cause damage to
roadways.
Hazard maps available through ABAG and produced by the USGS depict
liquefaction and lateral spreading hazards for the entire Bay Area
in the event of a significant seismic event (ABAG, 2009d).6
According to these maps, the project area has moderate liquefaction
susceptibility. However, the geotechnical site investigation for
the proposed new patient care pavilion hospital tower indicated
that the soils are relatively dense and the groundwater level was
recorded at approximately 47 below ground surface indicating a low
probability for liquefaction (Geomatrix, 2008a). The geotechnical
site investigation for the proposed new central parking structure
concluded that the western half of the proposed site might be
subject to liquefiable sandy layers observed at depths below
approximately 32 feet (AMEC, 2009).
Landslides Slope failures, commonly referred to as landslides,
include many phenomena that involve the downslope displacement and
movement of material, either triggered by static (i.e., gravity) or
dynamic (i.e., earthquake) forces. A slope failure is a mass of
rock, soil, and debris displaced downslope by sliding, flowing, or
falling. Exposed rock slopes undergo rockfalls, rockslides, or rock
avalanches, while soil slopes experience shallow soil slides, rapid
debris flows, and deep- seated rotational slides. Landslides may
occur on slopes of 15 percent or less; however, the probability is
greater on steeper slopes that exhibit old landslide features such
as scarps, slanted vegetation, and transverse ridges.
Landslide-susceptible areas are characterized by steep slopes and
downslope creep of surface materials. Debris flows consist of a
loose mass of rocks and other granular material that, if saturated
and present on a steep slope, can move downslope. The rate of rock
and soil movement can vary from a slow creep over many years to a
sudden mass movement. Landslides occur throughout the state of
California, but the density of incidents increases in zones of
active faulting.
The project site is not located in an area where earthquake-induced
landslides are likely to occur because of the relatively gentle
slopes of the project area. Therefore, the risk of landslide at the
site is low and is not discussed further in this analysis.
6 Lateral spreading is a ground failure associated with
liquefaction and generally results from predominantly
horizontal displacement of materials toward relatively unsupported
free slope faces.
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-8 ESA / 207376 Master
Plan Project Draft EIR December 2009
Geologic Hazards Considering the geologic context of the project
area and nature of the project, other typical geologic hazards
could include soil erosion and expansive soil. These hazards are
discussed briefly here.
Expansive Soils Expansive soils possess a “shrink-swell” behavior.
Shrink-swell is the cyclic change in volume (expansion and
contraction) that occurs in fine-grained clay sediments from the
process of wetting and drying. Structural damage to buildings can
occur over a long period of time, usually as a result of inadequate
soil and foundation engineering or the placement of structures
directly on expansive soils. Soils in the area have been
characterized as having a medium to high expansion potential, or
shrink-swell behavior. According to the initial geotechnical
evaluation no expansive soils were identified at the project site
(Geomatrix, 2008a). However, a supplemental investigation
identified an area with near surface fill materials that were
considered to be potential expansive (Geomatrix, 2008b). In
addition, the geotechnical investigation for the proposed central
parking structure found clayey soils in the western portion of the
proposed garage site that are considered highly expansive (AMEC,
2009).
Soil Erosion Erosion is the wearing away of soil and rock by
processes such as mechanical or chemical weathering, mass wasting,
the action of waves, wind and underground water. Excessive soil
erosion can eventually lead to damage of building foundations and
roadways. The proposed project includes excavation for graded
soils, use of fill material, and possibly additional imported soil
material. However, as part of building design requirements, the
project area will be sloped for rapid removal of surface water
runoff from the foundation systems, which would reduce the risk of
soil erosion that would lead to damage of building foundations and
roadways.
4.8.2 Regulatory Setting
California Building Code The California Building Code (CBC) has
been codified in the California Code of Regulations (CCR) as Title
24, Part 2. Title 24 is administered by the California Building
Standards Commission, which by law is responsible for coordinating
all building standards. Under state law, all building standards
must be centralized in Title 24 or they are not enforceable. The
purpose of the CBC is to establish minimum standards to safeguard
the public health, safety and general welfare through structural
strength, means of egress facilities, and general stability by
regulating and controlling the design, construction, quality of
materials, use and occupancy, location, and maintenance of all
building and structures within its jurisdiction. The CBC is based
on the International Building Code. The 2007 CBC is based on the
2006 International Building Code (IBC) published by the
International Code Conference. In addition, the CBC contains
necessary California amendments, which are based on the American
Society of Civil Engineers (ASCE) Minimum Design Standards 7-05.
ASCE 7-05 provides requirements for general structural design and
includes means for determining earthquake loads as well as other
loads (flood, snow, wind, etc.) for inclusion into building codes.
The provisions
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of the CBC apply to the construction, alteration, movement,
replacement, and demolition of every building or structure or any
appurtenances connected or attached to such buildings or structures
throughout California.
The earthquake design requirements take into account the occupancy
category of the structure, site class, soil classifications, and
various seismic coefficients, which are used to determine a Seismic
Design Category (SDC) for a project. The SDC is a classification
system that combines the occupancy categories with the level of
expected ground motions at the site and ranges from SDC A (very
small seismic vulnerability) to SDC E/F (very high seismic
vulnerability and near a major fault). Design specifications are
then determined according to the SDC.
1983 Alfred E. Alquist Hospital Seismic Safety Act (Seismic Safety
Act), Senate Bill 1953 (SB 1953) and the OSHPD All acute care
medical center properties fall under the jurisdiction of the
Alquist Act, as amended in 1994 by SB 1953. The Alquist Act
requires medical facilities to comply with seismic safety building
standards as defined by the Office of Statewide Health Planning and
Development (OSHPD) within specific time frames.
OSHPD is a department of the California Health and Human Services
Agency and is responsible for carrying out the provisions of the
Alquist Act and serves as the building authority for acute care
facilities in lieu of local jurisdictions. OSHPD’s primary goals
include assessing California’s healthcare infrastructure, managing
the healthcare workforce, providing healthcare outcomes information
to the public, insuring healthcare facilities development loans,
and running the Hospital Seismic Safety Program, which enforces
building seismic safety. The Hospital Building Safety Board (HBSB)
further advises the director of OSHPD on the administration of the
Act and acts as a board of appeals for hospital seismic safety
issues.
The Act was adopted in part so that after a major earthquake or
disaster, hospital facilities can continue to provide care to their
current occupants as well as any new patients that might arrive
after the event. During and after the 1994 Northridge earthquake,
hospitals that were compliant with the Act sustained minimal
structural damage and continued to function. Hospitals that were
not compliant sustained major damage and had to be abandoned
(OSHPD, 2001).
Compliance with the Alquist Seismic Safety Act and SB 1953 (the
Act) For a hospital building to remain classified as an acute care
hospital facility, and thus be compliant with the Act, the owner of
the building must do the following:
1. Complete seismic evaluations with procedures as defined by OSHPD
to identify non- compliant buildings,
2. Prepare a comprehensive plan and schedule for how each building
will become compliant with the Act, within 3 years of the
evaluation, and
3. Submit the report and a compliance plan to OSHPD for review and
approval (California State Senate, 1994).
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In the process of compliance, OSHPD and the hospital building owner
evaluates both nonstructural (communications, medical gas, etc.)
and structural (actual building structure) components of acute care
hospital facilities that might sustain damage during a shaking
event. Nonstructural components are put into a Nonstructural
Performance Category (NPC), and structural components are put into
a Structural Performance Category (SPC). Thus, each acute care
facility is assigned an NPC rating and an SPC rating that is put
into OSHPD’s database for review. OSHPD evaluates SPC and NPC
ratings separately. As part of the ratings evaluation process,
OSHPD and affiliated engineers examine structural drawings and
submitted reports of upgrades, if any, that have occurred to each
hospital building. These evaluations may include an onsite visit by
the Area Compliance Officer (ACO) and/or the District Structural
Engineer (DSE) of OSHPD. After the evaluation process, the rating
is either confirmed or changed according to OSHPD’s review and
determination, and OSHPD provides guidance to the hospital property
owner regarding further required upgrades.
NPC and SPC Ratings Each possible NPC and SPC rating is described
below. In general, low ratings (e.g., SPC-1) mean a hospital
building systems are not prepared for a disaster, and high ratings
(e.g., SPC-4) mean hospital building systems are prepared for a
disaster. If the building is determined to not be in compliance
with the Act based on the following NPC and SPC ratings, seismic
retrofit regulations (Division III-R) shall be applied to guide the
building’s retrofit, thus increasing the NPC and SPC rating of the
building (OSHPD, 2001). New construction that is designed and
constructed to current seismic and building code standards would be
exempt from NPC and SPC ratings although in full compliance with
the Act.
Nonstructural Ratings
NPC-0: No rating was reported to OSHPD.
NPC-1: Basic systems used in life safety and care are not properly
anchored, and will not survive an earthquake event. Communications,
emergency power, medical gas, and fire alarm systems must be
anchored by January 1, 2002.
NPC-2: Communications systems, emergency power supplies, bulk
medical gas systems, fire alarm systems, and emergency lighting and
exit signs are properly anchored.
NPC-3: Basic systems used in life safety and care are properly
anchored in critical areas of the hospital. If there is not
significant structural damage, basic emergency medical care should
be able to continue.
NPC-4: All architectural, mechanical, electrical systems,
components and equipment, and hospital equipment are properly
anchored. If there is not significant structural damage and
problems with water and sewer systems, basic emergency medical care
should be able to continue.
NPC-5: All basic systems used in life safety and care are properly
anchored. In addition, the building has water and wastewater
holding tanks (integrated into the plumbing system) and an on-site
fuel supply that will last through 72 hours of acute care
operations.
Radiological service can also continue.
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
Structural Ratings
SPC-0: No rating was reported to OSHPD.
SPC-1: These buildings have a high risk of collapse in an
earthquake, and are a significant safety hazard to the public.
These buildings must be retrofitted, replaced, or removed from
acute care classification by January 1, 2008.
SPC-2: These buildings are in compliance with pre-1973 California
Building Code, but are not in compliance with the Alquist Hospital
Facilities Seismic Safety Act. These buildings do not pose a
significant safety hazard, but might not be functional after a
strong earthquake. These buildings must be compliant with the
Alquist Hospital Facilities Seismic Safety Act by January 1, 2030
or removed from acute care classification.
SPC-3: These buildings are compliant with the Alquist Hospital
Facilities Seismic Safety Act. These buildings might sustain
structural damage and might not be able to provide care after an
event, but they have been constructed or reconstructed under OSHPD
building permits. They can be used to January 1, 2030 and
beyond.
SPC-4: These buildings are compliant with the Alquist Hospital
Facilities Seismic Safety Act. These buildings may sustain
structural damage and might not be able to provide care after an
event, but they have been constructed or reconstructed under OSHPD
building permits. They can be used to January 1, 2030 and
beyond.
SPC-5: These buildings are compliant with the Alquist Hospital
Facilities Seismic Safety Act. These buildings are reasonably
capable of providing care after an event, and they have been
constructed or reconstructed under OSHPD building permits. They can
be used to January 1, 2030 and beyond.
For purposes of assessing the NPC and SPC ratings of the Merritt
Pavilion (the component of the proposed project that ABSMC is
undertaking specifically to comply with the operational and legal
mandates of SB 1953), the Merritt Pavilion, which is the main
hospital building that houses the patient care and emergency
services facilities, is made of up 17 individual structures. Each
structure has its own NPC and SPC rating. All 17 structures have an
NPC-1 rating. Of the 17 structures, 10 structures that are the
oldest (built prior to 1964) and that generally make up the
northern half of the pavilion, have an SPC-1 or SPC-2 rating. The
remaining 7 structures are newer (built after 1974) and have SPC
ratings ranging from SPC-3 to SPC-5 (Degenkolb, 2004).
City of Oakland Regulations
Ordinances and Oakland Municipal Code The City of Oakland
implements the following regulations and ordinances aimed at
reducing soil erosion and protecting water quality and water
resources:
The City’s Grading Ordinance (Ordinance No. 10312 is intended to
reduce erosion during grading and construction activities. Pursuant
to this ordinance, Chapter 13.16 of the Oakland Municipal Code
requires that a project applicant obtain grading permits for earth
moving activities under specified conditions of 1) volume of earth
to be moved, 2) slope characteristics, 3) areas where "land
disturbance" or 4) stability problems have been reported. To obtain
a grading permit, the
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
project applicant must prepare and submit to the Public Works
Agency a soils report, a grading plan, and an erosion and
sedimentation control plan for approval (Oakland Municipal Code,
2008).
The City also implements the Sedimentation and Erosion Control
Ordinance (Ordinance No. 10446) also aimed at reducing erosion
during construction and operations. As a condition of development
or redevelopment, the Chief of Building Services or his or her
designee may require implementation of continuous or post
construction best management practices such as good housekeeping
practices or storm water treatment systems (Oakland Municipal Code,
2008).
Building Services Division In addition to compliance with building
standards set forth by the 2006 IBC and 2007 CBC, the project
applicant will be required to submit to the Oakland Building
Services Division an engineering analysis accompanied by detailed
engineering drawings for review and approval prior to excavation,
grading, or construction activities on the project site.
Specifically, an engineering analysis report and drawings of
relevant grading or construction activities on a project site would
be required to address constraints and incorporate recommendations
identified in geotechnical investigations. These required
submittals and City reviews ensure that the buildings are designed
and constructed in conformance with the seismic and other
requirements of all applicable building code regulations, pursuant
to standard City of Oakland procedures.
City of Oakland Standard Conditions of Approval and Uniformly
Applied Development Standards Imposed as Standard Conditions of
Approval The City’s Standard Conditions of Approval relevant to
geology and soils are listed below for reference. If the proposed
project is approved by the City, then all applicable Standard
Conditions of Approval would be adopted as conditions of approval
and required of the project to help ensure less-than-significant
impacts to geology and soils. The Standard Conditions of Approval
are incorporated and required as part of the project, so they are
not listed as mitigation measures. Standard Conditions of Approval
applicable to potential geologic impacts due to the project
include:
GEO-1: Erosion and Sedimentation Control Plan
Prior to any grading activities.
a) The project applicant shall obtain a grading permit if required
by the Oakland Grading Regulations pursuant to Section 15.04.780 of
the Oakland Municipal Code. The grading permit application shall
include an erosion and sedimentation control plan for review and
approval by the Building Services Division. The erosion and
sedimentation control plan shall include all necessary measures to
be taken to prevent excessive stormwater runoff or carrying by
stormwater runoff of solid materials on to lands of adjacent
property owners, public streets, or to creeks as a result of
conditions created by grading operations. The plan shall include,
but not be limited to, such measures as short-term erosion control
planting, waterproof slope covering, check dams, interceptor
ditches, benches, storm drains, dissipation structures, diversion
dikes, retarding berms and barriers, devices to trap, store and
filter out sediment, and stormwater retention basins. Off-site work
by the project applicant may be necessary.
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-13 ESA / 207376 Master
Plan Project Draft EIR December 2009
The project applicant shall obtain permission or easements
necessary for off-site work. There shall be a clear notation that
the plan is subject to changes as changing conditions occur.
Calculations of anticipated stormwater runoff and sediment volumes
shall be included, if required by the Director of Development or
designee. The plan shall specify that, after construction is
complete, the project applicant shall ensure that the storm drain
system shall be inspected and that the project applicant shall
clear the system of any debris or sediment.
Ongoing throughout grading and construction activities.
b) The project applicant shall implement the approved erosion and
sedimentation plan. No grading shall occur during the wet weather
season (October 15 through April 15) unless specifically authorized
in writing by the Building Services Division.
GEO-2: Vibrations Adjacent Historic Structures
Prior to issuance of a demolition, grading or building permit. The
project applicant shall retain a structural engineer or other
appropriate professional to determine threshold levels of vibration
and cracking that could damage the adjacent historic structure and
design means and methods of construction that shall be utilized to
not exceed the thresholds.
GEO-3: Soils Report
Required as part of the submittal of a Tentative Tract or Tentative
Parcel Map. A preliminary soils report for each construction site
within the project area shall be required as part if this project
and submitted for review and approval by the Building Services
Division. The soils reports shall be based, at least in part, on
information obtained from on-site testing. Specifically the minimum
contents of the report should include:
A. Logs of borings and/or profiles of test pits and trenches: a)
The minimum number of borings acceptable, when not used in
combination
with test pits or trenches, shall be two (2), when in the opinion
of the Soils Engineer such borings shall be sufficient to establish
a soils profile suitable for the design of all the footings,
foundations, and retaining structures.
b) The depth of each boring shall be sufficient to provide adequate
design criteria for all proposed structures.
c) All boring logs shall be included in the soils report.
B. Test pits and trenches a) Test pits and trenches shall be of
sufficient length and depth to establish a
suitable soils profile for the design of all proposed structures.
b) Soils profiles of all test pits and trenches shall be included
in the soils report.
C. A plat shall be included which shows the relationship of all the
borings, test pits, and trenches to the exterior boundary of the
site. The plat shall also show the location of all proposed site
improvements. All proposed improvements shall be labeled.
D. Copies of all data generated by the field and/or laboratory
testing to determine allowable soil bearing pressures, sheer
strength, active and passive pressures, maximum allowable slopes
where applicable and any other information which may
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
be required for the proper design of foundations, retaining walls,
and other structures to be erected subsequent to or concurrent with
work done under the grading permit.
E. Soils Report. A written report shall be submitted which shall
include, but is not limited to, the following: a) Site description;
b) Local and site geology; c) Review of previous field and
laboratory investigations for the site; d) Review of information on
or in the vicinity of the site on file at the Information
Counter, City of Oakland, Office of Planning and Building; e) Site
stability shall be addressed with particular attention to existing
conditions
and proposed corrective attention to existing conditions and
proposed corrective actions at locations where land stability
problems exist;
f) Conclusions and recommendations for foundations and retaining
structures, resistance to lateral loading, slopes, and
specifications, for fills, and pavement design as required;
g) Conclusions and recommendations for temporary and permanent
erosion control and drainage. If not provided in a separate report
they shall be appended to the required soils report;
h) All other items which a Soils Engineer deems necessary; i) The
signature and registration number of the Civil Engineer preparing
the report.
F. The Director of Planning and Building may reject a report that
she/he believes is not sufficient. The Director of Planning and
Building may refuse to accept a soils report if the certification
date of the responsible soils engineer on said document is more
than three years old. In this instance, the Director may be require
that the old soils report be recertified, that an addendum to the
soils report be submitted, or that a new soils report be
provided.
GEO-4: Geotechnical Report
Required as part of the submittal of a tentative Tract Map or
tentative Parcel Map. a) A site-specific, design level, Fault Zone
geotechnical investigation for each
construction site within the project area shall be required as part
if this project and submitted for review and approval to the
Building Services Division. Specifically: i. Each investigation
shall include an analysis of expected ground motions at the
site from identified faults. The analyses shall be accordance with
applicable City ordinances and polices, and consistent with the
most recent version of the California Building Code, which requires
structural design that can accommodate ground accelerations
expected from identified faults.
ii. The investigations shall determine final design parameters for
the walls, foundations, foundation slabs, surrounding related
improvements, and infrastructure (utilities, roadways, parking
lots, and sidewalks).
iii. The investigations shall be reviewed and approved by a
registered geotechnical engineer. All recommendations by the
project engineer, geotechnical engineer, shall be included in the
final design, as approved by the City of Oakland.
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
iv. The geotechnical report shall include a map prepared by a land
surveyor or civil engineer that shows all field work and location
of the “No Build” zone. The map shall include a statement that the
locations and limitations of the geologic features are accurate
representations of said features as they exist on the ground, were
placed on this map by the surveyor, the civil engineer or under
their supervision, and are accurate to the best of their
knowledge.
v. Recommendations that are applicable to foundation design,
earthwork, and site preparation that were prepared prior to or
during the projects design phase, shall be incorporated in the
project.
vi. Final seismic considerations for the site shall be submitted to
and approved by the City of Oakland Building Services Division
prior to commencement of the project.
vii. A peer review is required for the Geotechnical Report.
Personnel reviewing the geologic report shall approve the report,
reject it, or withhold approval pending the submission by the
applicant or subdivider of further geologic and engineering studies
to more adequately define active fault traces.
b) Tentative Tract or Parcel Map approvals shall require, but not
be limited to, approval of the Geotechnical Report.
4.8.3 Impacts and Mitigation Measures
Significance Criteria The project would have a significant impact
on the environment if it would:
Specifically,
1. Expose people or structures to substantial risk of loss, injury,
or death involving:
• Rupture of a known earthquake fault, as delineated on the most
recent Alquist-Priolo Earthquake Fault Zoning Map or Seismic
Hazards Map issued by the State Geologist for the area or based on
other substantial evidence of a known fault (refer to Division of
Mines and Geology Special Publications 42 and 117 and PRC §2690 et.
seq.);
• Strong seismic ground shaking; • Seismic-related ground failure,
including liquefaction, lateral spreading, subsidence,
collapse; or • Landslides;
2. Result in substantial soil erosion or the loss of topsoil,
creating substantial risks to life, property, or
creeks/waterways;
3. Be located on expansive soils, as defined in Table 18-1-B of the
Uniform Building Code (1994, as it may be revised), creating
substantial risks to life or property;
4. Be located above a well, pit, swamp, mound, tank vault, or
unmarked sewer line, creating substantial risks to life or
property;
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-16 ESA / 207376 Master
Plan Project Draft EIR December 2009
5. Be located above landfills for which there is no approved
closure and post-closure plan, or unknown fill soils, creating
substantial risks to life or property; or
6. Have soils incapable of adequately supporting the use of septic
tanks or alternative wastewater disposal systems where sewers are
not available for the disposal of wastewater.
Approach to Analysis Based on the proposed project plan and its
geographical location, the proposed project would not result in
impacts related to the following criteria. No impact discussion is
provided for these topics for the following reasons:
• Fault Rupture. The faults most susceptible to earthquake rupture
are active faults, which are faults that have experienced surface
displacement within the last 11,000 years. There are no active
faults that cross the project area, and the nearest project
facility to an active fault is more than 2 miles away. Therefore,
the potential for fault rupture to affect the proposed project
elements is very low.
• Landslides. The Plan area does not contain slopes that are
susceptible to landslides or slope failure. The gentle sloping
topography of the area puts the potential for landslides or slope
failure to affect any of the proposed development or redevelopment
in the Plan area at very low and is therefore not discussed
further.
• Wastewater Disposal. The Project area is located within an urban
area where all development will be able to tie into existing
wastewater infrastructure. Therefore, none of the development or
redevelopment will require the use of septic or other alternative
disposal wastewater systems, and therefore no impact associated
with this hazard.
Compliance with Seismic Safety Act A primary objective of the
proposed project is redevelopment of the acute care facilities to
comply with the Alquist Seismic Safety Act (SB 1953) by the
deadline of January 1, 2013. The proposed project will assure that
medical services will continue to be provided by a licensed acute
care facility on the existing site during construction and
thereafter without disruption. The principal objectives also
include construction of new medical office buildings, classrooms
and other structures which are not considered an essential
structure and do not fall under the guidelines presented in
California Geological Survey – Note 48, Checklist for the Review of
Engineering Geology and Seismology Reports for California Public
Schools, Hospitals, and Essential Services Buildings (Note 48). The
main purpose of the proposed project is to meet the provisions of
SB 1953 by 2013. Construction of new acute care facility buildings
according to the 2007 California Building Code, would meet the
requirements of the Act.
Operational Impacts
Impact GEO-1: Redevelopment in the project area could expose people
or structures to seismic hazards such as groundshaking or
liquefaction. (Less than Significant)
The proposed project is located in the San Francisco Bay Area, a
region of intense seismic activity. Recent studies by the USGS
indicate there is a 62 percent likelihood of a Richter magnitude
6.7
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-17 ESA / 207376 Master
Plan Project Draft EIR December 2009
or higher earthquake occurring in the Bay Area before 2032. The
Hayward Fault Zone, the active fault nearest the project site, is
the most likely of the active Bay Area faults to experience a major
earthquake. A seismic event in the Bay Area could produce ground
shaking at the proposed project area that is very strong (MM-VIII)
(ABAG, 2009c). Seismic shaking can also trigger ground-failures
caused by liquefaction.7 The project site is not located in a
Seismic Hazard Zone for liquefaction, as designated by the CGS
(CGS, 2009). In addition, the geotechnical investigation prepared
for the proposed new patient care pavilion hospital tower indicated
that based on observed subsurface materials taken during field
exploration and an observed depth to groundwater of approximately
47 feet below grade, the potential for liquefaction was very low
(Geomatrix, 2008a). However, the geotechnical investigation
prepared for the proposed central parking structure found that the
western portion of the garage site had saturated sand layers that
have a moderate to high potential for liquefaction (AMEC, 2009).
The report also concluded that deep foundation systems such as
drilled piers could effectively mitigate the potential for
liquefaction for the proposed structure.
Based on the MMI scale, an earthquake of this intensity on the
Hayward fault would cause considerable structural damage, even in
well-designed structures. Ground shaking of this intensity could
lead to structural building damage, movement or damage of internal
building components, or power failure. Substantial cracks could
appear in the ground, and the shaking could cause other secondary
damaging effects such as the failure of underground pipes. As a
comparison, the great 1906 San Francisco earthquake, with an M 7.9,
produced strong (MM-VII) shaking intensities in the project area
(ABAG, 2008a). A characteristic earthquake on the Calaveras, San
Andreas, or Concord-Green Valley (listed in Table 4.8-2) could
produce moderate (MM-VI) to strong (MM-V) ground shaking
intensities (ABAG, 2008a). Earthquakes of this intensity may move
heavy furniture and cause slight damage.
In accordance with the State Health and Safety Code, the OSHPD is
required to review the structural systems and related details of
the construction or renovation of medical buildings with acute care
facilities, as well as the recommendations of any site-specific
geotechnical investigations prepared for those buildings, to ensure
compliance with the Seismic Safety Act and the CBC. OSHPD’s
comments and the recommendations from the geotechnical
investigation would be submitted to the City of Oakland Building
Services Division. However, local jurisdictions are preempted from
the enforcement of all building standards published in the
California Building Standards Code relating to the regulation of
hospital buildings and the enforcement of other regulations adopted
pursuant to the State Health and Safety Code and all other
applicable state laws. In addition to reviewing the proposed
structural plans, OSHPD is responsible for overseeing construction
of the proposed hospital building to ensure that construction
complies with the approved plans. For all proposed non-acute care
facilities such as parking structures, the Project Sponsor would be
required to adhere to the California Building Code and City of
Oakland Building Services Division requirements.
7 Liquefaction is the process by which saturated, loose,
fine-grained, granular, soil, like sand, behaves like a dense
fluid when subjected to prolonged shaking during an
earthquake.
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
In accordance with City of Oakland requirements, the Project
Sponsor would be required to prepare a geotechnical report for the
project that includes generally accepted and appropriate
engineering techniques for determining the susceptibility of the
project site to various geologic and seismic hazards. The
geotechnical report would include an analysis of ground shaking
effects, liquefaction potential, and provide recommendations to
reduce these hazards. Because the project site is within a Seismic
Hazard Zone for liquefaction, recommendations for the mitigation
and reduction of liquefaction would be prepared in accordance with
CGS Guidelines for Evaluating and Mitigating Seismic Hazards
(California Division of Mines and Geology Special Publication 117,
1997). Geotechnical and seismic design criteria would conform to
engineering recommendations consistent with the seismic
requirements set forth in the California Code of Regulations, Title
24, California Building Standards Code in effect at the time of
permit application.
In addition to compliance with building standards set forth in the
California Code of Regulations, Title 24, California Building
Standards Code, the project sponsor would be required to submit an
engineering analysis accompanied by detailed engineering drawings
to the City of Oakland Building Services Division prior to
excavation, grading, or construction activities on the project
site. This is consistent with standard City of Oakland practices to
ensure that all buildings are designed and built in conformance
with the seismic requirements of the City of Oakland Building Code.
An engineering analysis report and drawings and relevant grading or
construction activities on a project site would be required to
address constraints and incorporate recommendations identified in
geotechnical investigations. These required submittals ensure that
the buildings are designed and constructed in conformance with the
requirements of all applicable building code regulations, pursuant
to standard City procedures. Standard Condition GEO-4, Geotechnical
Report, in addition to the OSHPD requirements would ensure that the
project conforms to all applicable building code regulations.
Construction according to these requirements would ensure that
potential impacts from seismic groundshaking or liquefaction would
be reduced to less than significant levels.
Mitigation: None required.
Impact GEO-2: Redevelopment in the project area could be subjected
to geologic hazards, including expansive soils, subsidence,
seismically induced settlement and differential settlement. (Less
than Significant)
Soils containing a high percentage of clays are generally most
susceptible to expansion. Expansive soils can damage foundations of
above-ground structures, paved roads and streets, and concrete
slabs. As previously discussed, the geotechnical evaluation
originally reported that expansive soils were not known to be
present on the project site for the proposed new patient care
pavilion but were observed at the proposed central parking
structure (Geomatrix, 2008a and AMEC, 2009). Also, in the
supplemental geotechnical report, further investigation revealed
that some near surface site soils were considered potentially
expansive. In addition, the findings of the geotechnical evaluation
concluded that due to the relatively dense and stiff alluvial
materials that subsidence and seismically induced settlement
(including differential settlement)
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
were unlikely at the site (Geomatrix, 2008a). The proposed
foundation for the project also includes the use of deep foundation
systems such as drilled piers, which would further mitigate any
potential damage from subsidence, seismically induced settlement or
differential settlement.
The geotechnical evaluation identified various construction methods
and building designs for all proposed structures under the project
that would serve to overcome the potential for these geologic
hazards at the site. Specifically, these methods include the use of
drilled piers or similar deep foundation systems, shallow mat
foundations with soil anchors, and industry standard site
preparation measures such as placement of engineered fill under
appropriate compaction specifications in compliance with building
code specifications (Geomatrix, 2008a and AMEC, 2009).
The City of Oakland requires preparation of a geotechnical report,
as well as compliance with and implementation of the geotechnical
report recommendations. Compliance with the geotechnical report
recommendations, required as part of Standard Condition GEO-4,
Geotechnical Report, would reduce the potential for the project to
result in geological hazards such as soil expansion and
differential settlement.
Mitigation: None required.
Cumulative Geology, Soils, and Seismicity Impacts
Cumulative Context As discussed above, the project would not result
in potentially significant project-level impacts related to
hazardous geologic and seismic conditions. Although the entire Bay
Area is situated within a seismically active region with a wide
range of geologic and soil conditions, these conditions can vary
widely within a short distance, making the cumulative context for
potential impacts resulting from exposing people and structures to
related risks one that is more localized or even site-specific. The
project site is located near other development and has the
opportunity to combine with structural damage from other past,
present, and reasonably foreseeable future projects. These include
projects within this area, and on the City of Oakland’s Active
Major Development Projects list provided on page 4.1-5, under
“Planned Projects within the Project Site Vicinity.”
Impact GEO-3: The development proposed as part of the project, when
combined with past, present, existing, approved, pending, and
reasonably foreseeable future development in the vicinity, would
not result in significant cumulative impacts with respect to
geology, soils or seismicity. (Less than Significant)
Development of the project, with implementation of the Standard
Conditions of Approval discussed above, would have less than
significant impacts related to exposing persons or structures to
geologic, soils, or seismic hazards. The project, combined with
other past, present, existing, approved, pending and reasonably
foreseeable future development in the area, could result in
increased population and development in an area subjected to
seismic risks and hazards. While the number of people visiting,
living and working in the area will increase incrementally,
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
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Plan Project Draft EIR December 2009
exposing additional people to seismic and geological hazards over
time, the risk to people and property would be reduced through the
upgrading or demolishing of older buildings that are seismically
unsafe. Older buildings would be seismically retrofitted and newer
buildings would be constructed to stricter building codes. Thus,
implementation of the proposed project and other foreseeable
projects in the area would be required to implement applicable
Standard Conditions of Approval related to geology, soils, and
seismicity (Standard Conditions GEO-1, Erosion and Sedimentation
Control Plan, GEO-2, Vibrations Adjacent to Historic Structures,
GEO-3, Soils Report, and GEO-4, Geotechnical Report), and would be
required to adhere to all federal, state, and local programs,
requirements and policies pertaining to building safety and
construction permitting. All projects would be required to adhere
to the City’s Building Code and grading ordinance. Therefore, the
project, combined with other foreseeable development in the area,
would not result in a cumulatively significant impact by exposing
people or structures to risk related to geologic hazards, soils,
and/or seismic conditions.
Mitigation: None required.
Parking Structure, Oakland CA, March 2009.
Association of Bay Area Governments (ABAG), ABAG Shaking Intensity
Maps and Information, 1989 Loma Prieta Earthquake Modeled shaking
for Oakland – North,
http://gis.abag.ca.gov/website/Shaking-Maps/viewer.htm, accessed
March 2009 (2009a).
Association of Bay Area Governments (ABAG), ABAG Shaking Intensity
Maps and Information, 1906 San Andreas Earthquake Modeled shaking
for Oakland – North
http://gis.abag.ca.gov/website/Shaking-Maps/viewer.htm, accessed
March 2009 (2009b).
Association of Bay Area Governments (ABAG), ABAG Shaking Intensity
Maps and Information, Future Shaking Modeled Shaking Scenario
Oakland-North,
http://gis.abag.ca.gov/website/Shaking-Maps/viewer.htm, accessed
March 2009 (2009c).
Association of Bay Area Governments (ABAG), ABAG Liquefaction Maps
and Information,
http://www.abag.ca.gov/bayarea/eqmaps/liquefac/liquefac.html,
accessed March 2009 (2009d).
Association of Bay Area Governments (ABAG), 2008. On Shaky Ground;
Modified Mercalli Intensity Scale., available online at
www.abag.ca.gov/bayarea/eqmaps/doc/mmi.html, 2003.
California Geological Survey (CGS), 2002. How Earthquakes Are
Measured, CGS Note 32.
California Geological Survey (CGS), Seismic Shaking Hazards in
California, Based on the USGS/CGS Probabilistic Seismic Hazards
Assessment (PSHA) Model, 2003 (revised April
4. Environmental Setting, Impacts, Standard Conditions of Approval
and Mitigation Measures 4.8 Geology, Soils, and Geohazards
ABSMC Summit Campus Seismic Upgrade and 4.8-21 ESA / 207376 Master
Plan Project Draft EIR December 2009
2003),
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