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B.Earthquake Country


Experts predict that it is only a matter of time before California is hit by a large earthquake. Although severe earthquakes do not occur as frequently and as regularly as severe hurricanes, scientists with the U.S. Geological Survey have calculated over a 62% probability of at least one magnitude 6.7 or greater earthquake hitting the San Francisco Bay Area before 2030, and a 60% probability for southern California.202 Local officials expect that a severe earthquake could devastate California. As Larry Klein, Chairman of the California Seismic Safety Chairman put it, "If you close your eyes and imagine an earthquake happened instead of Katrina, the image would be the same: collapsed buildings, no running water or electricity, displaced citizens, and vast devastation."203 The economic costs also would be staggering. The California Geologic Survey estimates that a repeat of the 1906 earthquake would rupture four segments of the San Andreas Fault, causing approximately $54 billion in economic loss from building damage alone. And similar losses are estimated for a large magnitude quake in Southern California.204 California has responded to this risk through the enactment of various zoning provisions and design and building standards.

1.Seismic Design and Building Standards


California leads the world in seismic design, in part because scientists have been able to accumulate a large amount of earthquake data over the last century and in part because it makes economic sense to build strong buildings. The Transamerica Pyramid in San Francisco is one of the most notable examples of good seismic design. During the 1989 Loma Prieta earthquake, which measured 7.1 on the Richter Scale, the building shook for over a minute and the top floor swayed over one foot from side to side. The building was not damaged and no occupants were harmed because it had been constructed to withstand significant earthquake movement.205

The Transamerica Building demonstrates that it is possible to build structures that withstand even strong earthquakes. California’s building code sets forth two primary standards for structures, one for the construction of new buildings, and one for the reconstruction of preexisting essential buildings.206 Any proposed new structures must be designed and constructed to resist collapse from earthquakes.207 Preexisting structures that serve an essential public purpose, like hospitals and police stations, must be retrofitted to resist collapse and must remain functionally able to continue performing its public use after an earthquake. Preexisting schools must be retrofitted to resist collapse from earthquakes and must remain functionally able to serve as an emergency shelter, or must be rebuilt. If these buildings cannot be retrofitted to meet these standards they must be rebuilt or replaced.

The difference between these two standards recently took center stage in San Francisco, as officials and developers clashed over which standard should apply to the development of proposed residential high rise towers. The highrises were being built with an innovative structural design and would stand forty-five and fifty-five stories high, respectively. They are part of a new wave of proposed residential highrises in the area. Because residential structures do not fall into the essential services categories, the code requires only that the buildings be able to survive an earthquake without collapsing. The city, however threatened to block construction unless project engineers could demonstrate that the buildings could withstand a major earthquake and remain inhabitable, a standard that closely mirrors the stricter standard applied to hospitals, schools, and other essential public service buildings. The city’s chief engineer claimed that the city wanted to establish precedent in the way “high-rise condominiums [were] being build in California and need[ed] to adhere to a standard of care that considers public safety first.”208 The city was concerned that if the building was not held to a stricter standard than typically applied to new structures the city would face a severe housing and homelessness crisis in the event of a large earthquake.

Debate over appropriate seismic standards is not limited to California. Local officials in Memphis, Tennessee and other Midwest states along the Midwest’s New Madrid Seismic Zone (“NMSZ”) are currently debating whether to adopt building and design standards drafted by FEMA, known as the IBC2000, which closely mirror California’s seismic standards. An earthquake along the NMSZ would be a high catastrophic event, but the risk of such an event is so much lower than that in California (only one-fifth to one-tenth the risk of that in San Francisco or Los Angeles). Thus, local officials have to decide whether the added protections from the IBC2000 justify imposing significantly higher construction costs.209


a.Building Standards for Essential Buildings


Hospitals. In 1973, California passed legislation requiring that all hospitals be retrofitted to withstand earthquakes without collapsing, or be rebuilt. The law was passed in response to the 1971 Sylmar earthquake, in which four hospitals were severely damaged and evacuated, two hospital buildings collapsed, and over forty-five people were killed. After the 1994 Northridge earthquake, which forced twenty-three hospitals to suspend all or some of their services, the law was expanded to accelerate the timetable for retrofitting hospitals to survive earthquakes so that all retrofitting must be complete by 2008 or the hospitals must be replaced, and to require that all hospitals be retrofitted to be reasonably capable of providing services to the public after a disaster by 2030.210

The current challenge, however, is compliance. According to a 2001 study by California’s Office of Statewide Health Planning and Development, only 14% of hospitals in the Bay Area are expected to be structurally functional in the event of a strong earthquake. Fifty percent may have limited functionality caused by structural damage, and 36% “pose a significant risk of collapse.” As far as nonstructural performance (e.g., emergency power, medical equipment, fire alarms, emergency lighting), less than 1% of hospitals are expected to be fully functional after a strong earthquake.211 The rush to comply with the 2008 deadline has led to a flurry of hospital construction in the region, the costs of which are likely to be passed on to patients.212



Essential Services Buildings. Essential services buildings must also be retrofitted to withstand an earthquake without collapse and be able to continue to provide services, or be replaced.213 An essential services buildings is defined as “a fire station, police station, emergency operations center, California Highway Patrol office, sheriff's office, or emergency communication dispatch center.”214

Schools. Like hospitals and essential services buildings, schools must be retrofitted to withstand collapse in the event of an earthquake.215 Schools also must be reasonably capable of serving as an emergency shelter after an earthquake. Schools are regularly inspected for compliance with these standards.

b.Unreinforced Masonry Buildings


Unreinforced masonry buildings (“URM buildings”) are an exception to the general rule that preexisting non-essential buildings do not have to be retrofitted, because of the extreme risk URM buildings pose to human life. Although the definition of URM buildings varies from city to city, URM buildings generally are buildings in which the bricks or other masonry used in their construction are not strengthened with embedded structural steel bars. In an earthquake the bricks or other masonry tend to disconnect and fall outward, leading to a collapse of the building.

California requires cities within California’s seismically-active coastal zone, to develop a mitigation plan to reduce hazards from URM buildings.216 Acceptable mitigation plans under the law range from requiring mandatory strengthening, voluntary strengthening, notification of URM status, to merely placarding URM buildings. Only about half of the 251 cities located within California’s seismically active coastal zone require mandatory strengthening, while thirty-nine cities require only voluntary strengthening, and forty cities only require notification217 Accordingly, although approximately 98% of the state’s 25,550 URM buildings are in compliance, only two-thirds have been retrofitted to withstand collapse.



California’s URM law permits cities to exempt historic buildings from their URM mitigation plans. This is significant considering that over 20% of Bay Area URM buildings are designated historic.218 This exemption reflects the tension between historic preservation and public safety and the difficulty balancing two goals that frequently are in direct conflict. It is often difficult to retrofit historic buildings without adversely affecting the unique features contributing to the buildings’ historic importance.219 There are several resources available to assist historic property owners evaluate and decide whether to retrofit their historic buildings.220

2.Zoning


California law restricts development of structures used for human occupancy along active faults, to prevent hazards associated with surface faulting.221 The law directs the State of California Division of Mines and Geology to create detailed maps of active faults on topographic maps and to distribute the maps to cities and counties and to various state agencies to be used in planning and regulating new construction.222 Before any construction is permitted, cities and counties must require a geologic investigation to demonstrate that a non-exempt223 structure will not be constructed along an active fault, and that it is set back at least fifty feet from the fault.224 The law also requires that real estate agents notify purchasers of property located in an earthquake zone.


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