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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty 2 The Role of Seismic Monitoring in Decision-Making This chapter describes the role of seismic monitoring in the decision-making process and provides examples of how seismic monitoring has been used successfully in the past. The three key components of decision-making that use seismic monitoring are: Risk assessment—the role of monitoring in reducing risk and uncertainty. Risk perception and choice—how individuals, groups, and organizations process information from seismic monitoring data and how this information influences their choices. Risk management—the role of seismic monitoring as a contributor to strategies for dealing with earthquake hazards. Risk assessment provides an understanding of the nature of risks—and their uncertainties—associated with disasters of different magnitudes, requiring input from the engineering and natural sciences disciplines. In the present context, this requires an understanding of the role that seismic monitoring plays in estimating earthquake risk, and how it can aid in reducing the uncertainties associated with these estimates. Risk perception and choice is concerned with the way earthquake monitoring data determines how individuals and organizations perceive their risk and make decisions in the context of the uncertainties surrounding the risk. Risk management describes the role of seismic monitoring in developing alternative strategies for reducing future losses and aiding the recovery process. An assessment of the contribution of seismic monitoring to disaster miti-
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty gation and management must be based on the integration of these three components. These elements—described in more detail in the following sections—provide the basis for evaluating the prospective benefits and projected costs of seismic monitoring in specific regions of the country. RISK ASSESSMENT: THE ROLE OF MONITORING IN DEFINING RISK AND REDUCING UNCERTAINTY Assessing the risk of earthquake damage to structures requires information concerning the type of structure and its response to strong ground motion and other seismic hazards, location of the structure in relation to earthquake faults, type of faulting, and overall distribution of strong ground shaking and its local modification by specific site geology. Quantitative estimates of seismic risk are important for judging whether earthquakes represent a substantial threat at any location; they enable objective weighting of earthquake risk relative to other natural hazards and other priorities for making design and retrofit decisions (NRC, 1996). Earthquake risk assessment encompasses the range of studies required to estimate the likelihood and potential consequences of a specific set of earthquakes of different magnitudes and intensities. Scientists and engineers are asked to provide the key decision-makers—those who will use earthquake risk assessment data—with a description of the nature of the earthquake risk in specific regions as well as the degree of uncertainty surrounding such estimates. The essential role of seismic information is to reduce the uncertainty in risk assessment over time and thereby increase its usefulness for emergency preparedness, loss avoidance regulation, private risk financing and insurance, and/or earthquake prediction. As improved monitoring provides increasing amounts of information, a more complete understanding of geophysical processes, more realistic models, and better-informed risk assessments will become possible. As the Advanced National Seismic System (ANSS) produces improved information, it will be possible to design better safety and regulatory programs, to generate improved ShakeMaps after earthquake events, and to improve earthquake prediction capabilities. Within the range of geological and geophysical investigations conducted under the auspices of the National Earthquake Hazard Reduction Program (NEHRP), seismic monitoring plays a key role in the definition
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty of the earthquake hazard—the foundation on which earthquake risk assessments are based. Seismic networks provide both parametric (e.g., earthquake origin times, locations, and magnitudes) and waveform or seismogram data. These data are used as the basis both for public safety decisions and for scientific and engineering research. Information about the locations of active faults and the size and frequency of damaging earthquakes allows decision-makers to specify appropriate design features of structures, using the seismic provisions in building codes. One component of this work is the development of “earthquake design ground motion libraries,” where strong motion records from a number of different earthquakes are processed in a consistent manner and made available to earthquake engineers and researchers in a web-accessible format for a variety of magnitude, distance, and fault types.1 The collection of high-quality data at close distances is critical for validating and verifying the earthquake engineering models that are used in the construction of our urban environment. An additional component in the risk assessment process is the development of an understanding of building performance or capacity. Measurements of building response during actual earthquakes provide empirical information on seismic performance and can also provide information for evaluating the efficacy of current mitigation engineering practices. The goal of performance-based earthquake engineering is enhanced knowledge of how buildings respond to earthquakes so that structures can be designed to achieve specific performance objectives (above and beyond the life safety requirements described in current building codes) (see Chapter 6). To illustrate how seismic monitoring can aid the risk assessment process, it is useful to consider a situation in which seismologists are asked to describe both the likelihood of earthquakes of various magnitudes occurring in the next 20 years (earthquake occurrence models) and the likelihood that the ground motions generated by these earthquakes will exceed some specified level (ground motion models). Seismologists can specify a probability distribution for a set of specific events, with bands of uncertainty that reflect the degree of confidence in these estimates (e.g., 95 percent confidence intervals). With increased seismic monitoring, scientists can refine both the earthquake occurrence models and the ground motion models, reducing the degree of uncertainty in those models. This information can then be used by engineers for estimating the likelihood of losses from earthquakes of different magnitudes as well as the degree of uncertainty surrounding these losses. 1 See http://peer.berkeley.edu/smcat/.
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty An example of the usefulness of this kind of information is provided by the Mw 6.8 Nisqually, Washington, earthquake of February 28, 2001. The first deployment of ANSS strong motion instruments had fortuitously been made in the Puget Sound region only a few months before the earthquake. These strong motion recordings provided valuable information about site response, its correlation with surface geology, the effect of nonlinear soil behavior on site response, and the amplitudes of basin surface waves in Seattle and the surrounding region (Frankel et al., 2002). The deployment of portable aftershock recorders following the earthquake provided additional useful information (see Figure 2.1). Immediately after a significant earthquake, there is a need to assess the extent and severity of damage and identify where emergency actions are needed. With the availability of ShakeMap, responders can pinpoint the areas of strongest shaking and focus their emergency response efforts quickly. One of the early uses of ShakeMap—a product developed in southern California in the years following the 1994 Northridge earthquake—was during the Nisqually earthquake. The ShakeMap software had just been installed in Seattle the previous month and was being used in a test mode, producing a ShakeMap within a few days of the earthquake. Subsequent aftershock monitoring emphasized the need for additional monitoring information. Comparison of ShakeMap contours of peak acceleration in Seattle using just the ANSS stations (left panel of Figure 2.1) compared with peak acceleration contours derived using the portable stations (described as “local network stations”; center panel of Figure 2.1) shows that the latter depicts a zone of strong shaking in central Seattle that was not identified using the ANSS stations alone. The latter panel has a much closer correspondence between the strong ground shaking in this region and the area that experienced damage, shown in the right panel, in which red dots indicate the locations of structural damage and ground deformation. By contributing to the seismic zonation of the Puget Sound region, especially in identifying locations that are potentially subject to large ground motion amplification or deamplification effects, seismic monitoring information enables seismologists and engineers to obtain more reliable estimates of the ground motion levels for which structures should be designed, thereby avoiding unnecessary conservatism in design. One way to capture what is known and not known about a particular risk is to construct an “exceedance probability” (EP) curve, to specify the probabilities that certain levels of losses will be exceeded. Losses can be measured in terms of dollars of damage, fatalities, injuries, or some other unit of analysis. This can be illustrated with a specific example of an EP curve for an insurer with a portfolio of residential earthquake policies in a California city. Using probabilistic risk assessment, it is possible to combine the set of events that could produce a given dollar loss and then
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty FIGURE 2.1 Comparison of ShakeMap contours of peak acceleration in Seattle from the 2001 Nisqually earthquake, using just the ANSS stations (left panel) and using the portable stations (center panel), shows that the latter map has a zone of strong shaking in central Seattle that was not identified using the ANSS stations alone. SOURCE: USGS (2003b).
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty determine the resulting probabilities of exceeding losses of different magnitudes. The mean EP curve for such a situation is shown in Figure 2.2, illustrating that for the specific loss Li, the likelihood that insured losses will exceed Li is given by pi. Any interested parties can construct an EP curve—to depict the uncertainty associated with the probability of an event occurring and the magnitude of dollar losses (Figure 2.3)—to satisfy their needs and concerns. A company located in a hazard-prone area may wish to determine the likelihood that it will suffer direct dollar damage and indirect losses—such as business interruption—that exceed different magnitudes in order to determine how much insurance to purchase. A building owner may want to examine how specific protective measures will shift the EP curve downwards, to provide an indication of the impact such investments will have on future dollar losses to its structure. As discussed further in Chapter 5, the large uncertainties associated with the likelihood and distribution of ground shaking, and with the damage to the built environment arising from shaking, significantly affect loss estimates. If these uncertainties can be reduced through seismic monitoring, they can lead to more cost-effective building design and construction decisions. FIGURE 2.2 Sample mean exceedance probability curve, showing that for a specified event the probability of insured losses exceeding Li is given by pi. SOURCE: Kunreuther et al. (2004).
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty FIGURE 2.3 An example exceedance probability curve showing uncertainty expressed as 5% and 95% confidence levels. The curve depicting the uncertainty in the loss shows the range of values, Li.05 to Li.95, that losses can take for a given mean value, Li; this indicates that there is a 95% chance that the loss will be exceeded with probability pi. Similarly, the curve describes the range of probabilities, pi.05 to pi.95, indicating that there is 95% certainty that losses will exceed Li. SOURCE: Grossi and Kunreuther (2005). In some areas of the United States, most notably in California, specific cost-effective risk mitigation measures are accepted (e.g., retrofit of unreinforced masonry buildings) and emergency response plans have well-articulated earthquake components. In these areas, scenario studies, which represent a horizontal slice through the EP curve in Figure 2.3, are used to estimate future losses, community vulnerabilities, and potential costs avoided through the implementation of mitigation strategies (see Box 1.5). Estimates of average annual loss, the area under the EP curve in Figure 2.3, are used by the NEHRP as a national and local measure and/or metric of seismic risk (depicted in Figure 1.6). However, in other parts of the country where damaging earthquakes occur less frequently, the risk is less well understood with the result that appropriate mitigation strategies are less clear and emergency response activities for earthquakes are less well established. Until the uncertainties surrounding the EP curve in Figure 2.3 are both reduced through continued monitoring and research and better understood by policy-makers, there will be either unnecessary or insufficient emergency response planning and inadequate mitigation
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty of structures because the experts in these areas are unable to inform decision-makers of the probabilities and potential outcomes with an appropriate degree of confidence. This lack of confidence leads to a large gray area within which either over- or under-recognition of the extent of the hazard can seem reasonable. RISK PERCEPTION AND CHOICE Risk assessment focuses on the likelihood of certain events occurring, with damage and loss often able to be measured in monetary units. In the context of earthquake risk assessment, improved seismic monitoring has the potential to refine quantitative risk estimates. In contrast, risk perception is concerned with psychological and emotional factors—qualitative elements that have been shown to have an enormous impact on behavior. A set of pioneering psychological studies begun in the 1970s measured laypersons’ concerns about different types of risks (Slovic, 2000) and showed that those hazards of which the person had little knowledge were perceived as being the most risky. For a long time, the scientific community felt that it was appropriate to ignore the public’s perception of risk if this differed significantly from its own estimates. There were many situations in which the public did not believe experts’ figures because they were poorly communicated, because the assumptions on which they were based were poorly stated, and/or because there was little understanding of the reasons why experts disagreed with each other. For example, Expert 1 might say that there is “nothing to worry about regarding a particular risk,” while at the same time the public would hear Expert 2 say that “this risk should be on your radar screen.” The situation has changed in recent years, with an increased understanding of the importance of incorporating psychological and emotional factors in evaluating how the public assesses risk. Rather than basing choices simply on the likelihood and consequences of different events, as normative models of decision-making suggest, there is now recognition that individuals are also influenced in their choices by past experiences that may be unrelated to the actual risk associated with future events. Surveys of homeowners in California support this point (Palm, 1998). These surveys suggest that the purchase of earthquake insurance is unrelated to any measure of seismic risk that is likely to be familiar to homeowners. Perceived risk, on the other hand, is a major predictor of earthquake insurance purchase. An illustration is provided by the Loma Prieta earthquake of 1989, which caused substantial damage to property in Santa Clara County and, to a lesser extent, in Contra Costa County. The percentage of earthquake-insured properties in Santa Clara County jumped
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty more than 10 percent in the year following the earthquake. In Contra Costa County, the percentage insured increased from 22 percent in 1989 to 37 percent in 1993. Even when no earthquakes have occurred in a given area, insurance purchase may increase if considerable concern is raised by media reporting. For example, there was a large increase in the demand for earthquake insurance in the New Madrid, Missouri, area when Iben Browning predicted that an earthquake would occur there in December of 1990 (see Spence et al., 1993, for description and analysis of this prediction). Even today, nearly 15 years later, a major insurer reports that more than half of its homeowners’ insurance buyers in Memphis, Tennessee, also purchase earthquake insurance—despite the fact that there has not been any significant seismic activity in the area in recent years. Individuals and businesses are not comfortable dealing with events in which there is considerable uncertainty regarding the likelihood of occurrence and the potential consequences. This aversion to ambiguity plays a role in the choices and decisions that individuals and businesses make with respect to high-impact, low-probability events such as earthquakes. Insurers who are trying to decide on premiums required for earthquake coverage provide an example—a series of empirical studies showed that actuaries and underwriters are so averse to ambiguity and risk that they tend to charge much higher premiums if the risk is poorly defined. Kunreuther et al. (1993) conducted a survey of 896 underwriters from 190 randomly chosen insurance companies to determine the premiums required to insure a factory against property damage from a severe earthquake. For the case in which both the probability and the losses were ambiguous, the premiums were between 1.43 and 1.77 times higher than if underwriters priced a nonambiguous risk. Similar results were observed in a study of actuaries in insurance companies (Hogarth and Kunreuther, 1989). The problems associated with risk perception and choice are compounded by the difficulties that individuals have in interpreting low probabilities when making decisions. In fact, there is evidence that people may not even want data on the likelihood of a specific event occurring. A study of several hypothetical risky managerial decisions shows that when individuals are required to search for their own information, they rarely ask for any data on probabilities (Huber et al., 1997). One group was given a minimal description and the opportunity to ask questions. Only 22 percent of these respondents asked for probability information, and not one asked for precise probabilities. Another group of respondents was given precise probability information, and less than 20 percent of these respondents mentioned the word “probability” or “likelihood” in their verbal description of the factors impacting their decision-making processes.
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty To the extent that seismic monitoring increases the perceived likelihood of future earthquakes in an area and reduces the uncertainty and ambiguity surrounding these estimates, individuals residing there are more likely to pay attention to the potential damage from a disaster. Insurers are also likely to set their premiums closer to the expected loss because of the reduction in ambiguity provided by the improved forecasting. Projects designed to reduce losses from natural or other disasters, such as improved seismic monitoring, are expected to provide benefits in the form of costs avoided. This means that the cost of such natural disasters—without mitigation measures such as improved building codes—must first be identified to establish a benchmark. This requires that, for any particular area, the probability distribution of possible earthquake disasters and the consequent expected dollar losses must be calculated, requiring a series of difficult estimates based on geologic and earthquake engineering projections. Each projected earthquake disaster event can be expected to cause structure damage and associated losses, business interruption losses, and infrastructure service losses. These three interact in complex ways, making the separate identification of each very difficult. IMPACT OF MONITORING ON RISK MANAGEMENT STRATEGIES In developing risk management strategies for earthquake hazards, the reduction in uncertainty associated with risk assessment due to seismic monitoring data must be integrated with the factors that have been shown to influence risk perception and choice. A framework for evaluating the impact of reductions of uncertainty has been proposed by Bernknopf et al. (1993) in the context of geologic map information that incorporates the type, structure, and engineering characteristics of a parcel of land. There is also now recognition of the need to define losses more broadly, to include both the direct impacts of a disaster (e.g., physical damage, direct business interruption, injuries and loss of lives) and the indirect losses (e.g., indirect business interruption, stress) (NRC, 1999; Heinz Center, 2000). This has made forecasting losses a more challenging task than when the focus was solely on direct property damage. Improved Forecasting. To the extent that earthquake monitoring can lead to an improvement in the accuracy of forecasts, it has the potential to reduce losses from future disasters. Consider two homeowners in different parts of California (Regions A and B) who are considering investing in mitigation measures to reduce future damage to their homes. Suppose that in the absence of adequate seismic monitoring information, there is no distinction made between the two regions, both of which have an estimated probability p of a damaging earthquake occurring next year. Using
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty this information as the basis for their choice, suppose that neither homeowner A nor homeowner B chooses to invest in mitigation. Both may be quite uncertain, however, whether this was the right decision to make. Now consider the case where the provision of seismic monitoring information enables differing likelihoods of damaging earthquakes in the two regions to be identified, with Region A having a probability pA > p and Region B having a probability pB < p. Based on these more refined data, property owners in Region A are more likely to invest in mitigation measures and those in Region B may not be concerned with taking this action. Both groups would be more certain about their decisions and less worried about the consequences of any earthquake than they would be without seismic monitoring. Homeowners in Region A will have strengthened their residences and feel more secure physically. Homeowners in Region B now know that they are much less likely to have a damaging earthquake in the future than before monitoring was instituted, and they believe that mitigation is not a cost-effective strategy to follow. Communicating Information on the Earthquake Risk. A number of studies indicate that people have difficulty assessing data regarding low-probability events (e.g., see Kunreuther et al., 2001). This poses challenges for effectively communicating information on these types of risk to the public. Improved seismic monitoring may lead to better communication of the risk because there will be less uncertainty regarding the likelihood of a future earthquake. It may also be possible to issue appropriate warnings about the dangers of earthquakes in particular regions of the country, leading to the adoption of risk reduction measures. Using Economic Incentives. It is possible to use economic incentives to encourage individuals to take protective measures. Here again seismic monitoring plays an important role in decisions about whether to invest in mitigation. For example, greater certainty regarding the risk will lead insurers to price these policies closer to expected losses. At the same time, the premiums can more accurately reflect differences in risk between regions. Consider two identical homes in the above two-region example. The insurance premium for homeowners in Region A would now be higher than for those in Region B because pA > pB. Prior to the availability of adequate seismic monitoring information, the premiums would be the same in the two regions because they would both be based on p. Consequently, property owners in Region A should be able to get a larger premium reduction by investing in mitigation. The insurer now knows that if homeowners in Region A strengthened their houses, the expected earthquake claims payment would be less than it originally anticipated given the higher probability of a damaging earthquake in that region. Incentive programs have been instituted in California to reduce losses from future earthquakes. Proposition 127, passed into law in November
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty 1990, states that seismic retrofitted improvements to property completed between January 1991 and July 2000 will not be reassessed by the county tax assessor until ownership changes. The state—having concluded that these improvements constitute a significant reduction in the risks to life and safety—repealed the July 2000 cutoff, or sunset date (Chapter 504 of Statutes of 1999, introduced as AB 1291). To the extent that seismic monitoring can identify anticipated reductions of losses and lives saved in specific earthquake-prone regions, property tax reductions potentially can be designed so that they more accurately reflect the expected benefits of mitigation. Building Codes. Building code regulations designed to mitigate seismic risk are desirable when property owners would otherwise not adopt cost-effective mitigation measures because they either misperceive their prospective benefits and/or underestimate the probability of a disaster occurring. When a building is substantially damaged or collapses, it may create losses to others in the form of economic dislocations and/or produce other social costs beyond the economic loss suffered by the owners. These losses would not be covered by the firm’s insurance policy. A well-enforced building code helps reduce these risks and obviates the need for financial assistance to those who would otherwise suffer uninsured losses. By providing more accurate data on the likelihood of earthquakes through seismic monitoring, there can be a more systematic application of the seismic design provisions of building codes for different parts of the country. DECISION-MAKERS/END-USERS AND THEIR ACTIONS The decision-makers who will utilize the results of seismic monitoring in developing risk management strategies include builders and engineers, property owners, insurers and reinsurers, lenders, public sector agencies, and lifeline organizations, with the potential impacts of these risk management decisions affecting the lives of millions of people and trillions of dollars of the national economy. Builders and Engineers. Developers, engineers, and contractors play an important role in the management of risk from earthquakes. Structures designed and built to high standards, combined with inspections by well-trained building officials, can provide good protection against casualties and property loss from earthquakes. Casualties and property loss are often attributable to inadequate design and construction practices. The problem of building and selling property in hazard-prone regions is exacerbated when uninformed design professionals and/or less reputable building contractors bypass costly seismic-resistant designs either that are not required by local codes or where the codes are not enforced (presented in more detail in Chapter 6).
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty Property Owners. Owners of commercial and residential structures that lack sufficient seismic resilience have a range of risk management strategies from which to choose. They can reduce their risk by demolishing a structure, retrofitting a structure to withstand earthquake loading, transferring part of their risk by purchasing some form of insurance, and/or keeping and financing their risk. Better seismic monitoring data will enable more informed decisions regarding the appropriate mitigation measures that should be adopted. Commercial property owners’ strategies to manage earthquake risks are different from those of residential owners. A commercial establishment must concern itself not only with life safety and insolvency issues, but also with the continued operation of its business activities following physical damage to its facilities and contents and/or infrastructure damage resulting in interruption of essential utility services (e.g., electricity, gas, water). Often there are extra expenses as a firm tries to remain viable after a catastrophe. Commercial establishments in hazard-prone regions are normally quite interested in purchasing business interruption insurance to protect themselves financially against these losses Insurance Sector. An insurer provides protection against losses resulting from earthquake damage—from ground shaking and/or ground deformation—to those who opt to purchase separate earthquake coverage. Insurers also provide coverage for damage caused by fire following an earthquake to all who buy property insurance policies. Earthquake insurance can be purchased as added coverage to a homeowner’s insurance policy; as a separate earthquake insurance policy; or, in California, through a state-run, privately funded earthquake insurance company—the California Earthquake Authority (CEA). In other states, earthquake insurance is provided solely by the private sector. Improved seismic monitoring will potentially provide better data to private insurers, reinsurers, and/or the CEA so they can more accurately price the coverage and manage their accumulations of risk. This will reduce the likelihood of the insurer’s suffering unexpectedly severe financial losses following a major earthquake event and, in turn, should increase the availability and lower the cost of coverage. Reinsurers accept and manage risk from insurers in the same way that insurers accept and manage risk from insurance buyers, and reinsurers must also price the coverage they offer and manage their accumulations of risk. They will also benefit from the availability of improved data, which will be reflected in increased reinsurance availability and lowered reinsurance cost. Lenders. Lenders play a vital role in managing natural disaster risk. Except for the uncommon case in which the owner pays for property out-right, banks and other financial institutions facilitate the purchase of a
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty home or business by providing mortgages. The property is the collateral in the event that the owner defaults on the mortgage. Lenders thus have a vital stake in the risk management process, because they are unlikely to recover the full value of a loan on a property destroyed by catastrophe. The 1994 Northridge earthquake, for example, generated $200 million to $400 million in mortgage-related losses in the Los Angeles area, and Freddie Mac2 experienced an unprecedented number of earthquake-related defaults on condominiums (Shah and Rosenbaum, 1996). Seismic monitoring data have the potential to provide lenders with more accurate information on the risk. With these data available, banks and financial institutions have economic incentives to protect their investments by requiring risk-reducing measures and/or insurance as a condition for a mortgage. Public Sector Agencies. Public sector agencies at the national and state levels should be able to design cost-effective earthquake mitigation and disaster preparedness programs that utilize the more accurate estimates of the risk obtained from seismic monitoring data. At the national level, the Federal Emergency Management Agency (FEMA) coordinates many of the planning and response activities related to catastrophes. FEMA has historically taken the lead in developing strategies for mitigation. For example, in December 1995, the agency introduced a National Mitigation Strategy with the objective of strengthening partnerships between all levels of government and the private sector to ensure safer communities. FEMA also provides funding to the Building Seismic Safety Council (BSSC) to develop the NEHRP Recommended Provisions for Seismic Regulation of New Buildings and Guidelines for the Seismic Rehabilitation of Existing Buildings (BSSC, 2004). These provisions and guidelines use the U.S. Geological Survey (USGS) national seismic hazard maps as the basis for defining the level of earthquake hazard for design and construction professionals. Improved seismic monitoring is the key to improving the accuracy of these maps, and public sector agencies would be able to use them in their design of seismic regulations and standards. At the state level, an office of emergency services or a department of public safety promotes natural disaster preparedness. Additionally, seismic safety commissions have been established by earthquake-prone states to prioritize earthquake research and public policy needs. Building codes that include criteria for earthquake resistance and legislation for land-use management endeavor to reduce risk. At the local level, communities 2 Freddie Mac is a government-sponsored entity that, along with Fannie Mae, provides a significant proportion of the funding for the secondary lending market by packaging mortgages and selling them to investors.
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty enforce building codes and have developed economic incentives, such as tax relief, for those who retrofit. Local communities develop programs to promote awareness, provide training, and encourage self-help actions through neighborhood emergency response teams. An example is the city of San Leandro, California, which has set priorities for retrofitting both unreinforced masonry buildings and older wood-frame homes. The city’s Home Earthquake Strengthening Program is a comprehensive, residential, seismic strengthening program that provides homeowners with simple and cost-effective methods for strengthening their wood-frame houses to enhance earthquake survival. The program includes earthquake-strengthening workshops for residents, a list of available contractors, as well as a tool-lending library for homeowners should they wish to do the work themselves. Improved data from seismic monitoring will enable both states and communities to adopt building codes and design economic incentives that more accurately reflect the risk than those currently in place. Lifeline Organizations. Lifeline organizations (including public and private utilities, transportation agencies, etc.) that provide water distribution and sewerage services, electric power, gas and liquid fuel, transportation, and communications play a vital role in the modern urban environment. Lifeline organizations are responsible for the resumption of critical services as soon as practical after an earthquake and have made significant investments to achieve this goal. The combined existing and planned expenditures for earthquake performance improvements for utilities and transportation systems in the San Francisco Bay area from 1987 to 2005 is estimated to be $15 billion.3 Improvements in the seismic design and post-earthquake operation of lifeline infrastructure are based on applied seismic research. The Pacific Earthquake Engineering Research Center (PEER) Lifelines Program (supported by the California Energy Commission, California Transportation Department [CalTrans], and Pacific Gas and Electric Company [PG&E]) and the Multidisciplinary Center for Earthquake Engineering Research (MCEER) (sponsored by the National Science Foundation and the Federal Highway Administration) are two examples of user-directed research programs that are actively involved in improving the safety and reliability of utility and transportation systems through the use of information collected by seismic monitoring. Networks of spatially distributed systems (transportation or utility systems) have a greater sensitivity to ground motions than individual (single-location) structures simply because the distributed system is affected over a larger area (especially for large-magnitude 3 Presentation to committee meeting by L.S. Cluff, December 16, 2003, San Francisco, California: The Role of Privately Owned Seismic Monitoring Networks.
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty events). Reduced uncertainty will enable better allocation of resources for new design and construction or for mitigation of older facilities. Strong motion recordings used to develop time histories for seismic qualification testing of individual components or equipment (e.g., the IEEE-693-97 Standard)4 provide critical information for improving electric utility safety and performance. Improved real-time monitoring of critical infrastructure (e.g., bridges, dams, rail lines, pipelines) will allow more efficient, prioritized inspections following earthquakes, as well as provide a means to monitor the long-term structural health of these facilities. In addition, federal regulations, such as the Department of Transport (DOT) Gas Transmission Pipeline Integrity Management in High Consequence Areas (49 CFR Part 192), require pipeline owners to collect information about earthquake faulting and ground acceleration as part of risk assessment and emergency response activities. TECHNOLOGY TRANSFER Technology transfer—outreach that explicitly seeks to apply new developments in science to solve practical community problems—is a vital component of the benefits from enhanced seismic monitoring. Technology transfer is distinct from public awareness or information campaigns, and the effective transfer or dissemination of new products and information to diverse types of users requires careful planning and well-articulated strategies. The information and products derived from seismic network data are potentially useful to engineers, emergency managers, policy-makers, planners, insurers, the news media, and others. Whereas engineers use monitored seismic information to better understand damage caused to buildings and infrastructure by strong ground motion and to recommend retrofit options and mitigation strategies, emergency managers, planners, and insurers need to know the probability of damaging earthquakes in their communities for planning purposes. Emergency managers also need rapid information on magnitude, location, and ground shaking for effective response. The news media provide important public information during an emergency and expect to receive rapid, accurate, and reliable information from the seismic networks. To benefit from seismic network products at an optimal level, these products may require modification and adaptation to the specific needs of these various constituencies. A prerequisite for the effective use of network products by non-science users 4 Institute of Electrical and Electronics Engineers, IEEE-693-97—Recommended Practices for the Seismic Design of Substations.
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty is an outreach effort designed to provide liaison between network operators and the users of network data. Interaction between data providers and data users should lead to an understanding of the available data—as well as their limitations—and should encourage opportunities for application of data products. A simple but instructive example of such a process is one that took place between the operators of the California Integrated Seismic Network (CISN) and representatives of the major news organizations in California. Shortly after the development and introduction of ShakeMap in the version that currently appears on the Internet, outreach efforts were initiated to develop a wider audience for this seismic network product. Television news, because of its ability to reach large audiences with information on a widely felt or damaging earthquake, was considered an important target audience. Workshops were held in Los Angeles and the San Francisco Bay area that brought together network operators and news organizations to present the capabilities of ShakeMap and discuss how it might be adapted for use in television and print journalism. An important result from the workshop and follow-up activities was a Media ShakeMap that preserved the color-coded display of shaking, but eliminated measures of velocity and acceleration that were not likely to be understood by a nonscientific audience (see Figures 2.4 and 2.5). Improved seismic monitoring will permit the production of accurate, site-specific ShakeMaps throughout the United States that depict the post-earthquake conditions on the ground; present systems permit such accuracy only in southern California. Technology transfer is also accomplished through a number of “intermediary” organizations that include—as part of their missions—the translation and dissemination of scientific research and new technology. Examples of such organizations are the Earthquake Engineering Research Institute (EERI); the Natural Hazards Research and Applications Information Center at the University of Colorado in Boulder; and the regional earth science and engineering centers funded by the National Science Foundation, the Federal Emergency Management Agency, and others. Technology transfer is accomplished through workshops involving scientists, engineers, and targeted users; by post-earthquake reconnaissance in which multidisciplinary teams investigate the impact of major earthquakes on the communities in which they occur; by the dissemination of publications that provide accessible information to users; and by formal training classes that disseminate new technologies for practical application. PUBLIC INFORMATION BENEFITS FROM MONITORING There are diverse demands for public information concerning earthquakes, ranging from curiosity (e.g., Was the shaking I felt because of an
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty FIGURE 2.4 ShakeMap for the Mw 6.5 San Simeon earthquake of December 22, 2003. SOURCE: USGS internet output. See http://earthquake.usgs.gov/shakemap/nc/shake/40148755/intensity.html. earthquake?) to the very urgent need for emergency instructions associated with a warning of imminent danger (e.g., a tsunami alert) or after the occurrence of a damaging event (e.g., Where can I sleep tonight now that my house has been destroyed?). Seismic monitoring data provide the basis for communication of an increased seismic potential for a region—information that may be presented as a long-term statement of seismic risk or
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty FIGURE 2.5 Media ShakeMap for the Mw 6.5 San Simeon earthquake of December 22, 2003; note the reduced amount of technical information compared to Figure 2.4. SOURCE: USGS internet output. See http://earthquake.usgs.gov/shakemap/nc/shake/40148755/download/tvmap.jpg. an announcement of an earthquake forecast in short or intermediate time frames. As tragically demonstrated by the 2004 Sumatran earthquake and tsunami, seismic monitoring information is of critical importance for communicating timely warnings that damaging tsunami waves may impact coastal communities. More typically, public information about earthquakes takes the form of announcements of magnitude, location, damage, and possibility of aftershocks following an earthquake. With recent advances in technology, it is quite possible to obtain basic seismic information before the first public or news media inquiry is received. The availability of such realtime information, however, is limited to those areas with dense networks of modern digital seismic stations and instantaneous communication of
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Improved Seismic Monitoring Improved Decision-Making: Assessing the Value of Reduced Uncertainty data to a central processing site. These network hubs have become centers for the provision of public information following any earthquake that achieves newsworthiness—usually an event that ranges from being widely felt to one that impacts the entire community or region. Typically, after such an earthquake occurs, the news media converge at the network hub and scientists interpret what has happened for the assembled journalists. The close relationship that has evolved in some regions between seismic network operators and the news media has facilitated the transfer of new knowledge and technologies to news organizations. As a result of these interactions, journalists become better-informed communicators of earthquake information to the public, and scientists become more aware of the needs of journalists for timely information in formats that are audience friendly. In addition, appreciation on the part of scientists of the critical link between the news media and the public has led to the development of specialized products designed to assist the media in communicating earthquake information to the public (e.g., Media ShakeMaps, real-time data feeds to news organizations). It should be emphasized that readily available seismic information, the communication of this information to the public through the news media, and the close working relationship between scientists and journalists are not uniform in all seismically active regions of the country. In those areas that are poorly monitored, information about the occurrence of earthquakes is inevitably less timely and less accurate, and in these areas opportunities to improve the public’s understanding of earthquakes, and the magnitude of the risk they pose, may be lost.
Representative terms from entire chapter: