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1 4. Dependencies and Cascading Effects

2 The development of a specific community disaster resilience plan requires an understanding of the 

3 building and infrastructure system dependencies and the potential cascading effects that can occur. This 

4 chapter provides an overview of aspects of the physical interconnectedness of buildings and infrastructure 

5 systems to consider when setting performance goals for community recovery.

6 4.1. Introduction

7 To determine the performance needed for the selected clusters of the built environment and to protect a 

8 community from significant and non-reversible deterioration, an orderly and rapid process for managing 

9 recovery is needed that includes availability of a sufficient number of buildings in each of the designated 

10 clusters and infrastructure systems that support them. Each cluster‟s performance depends not only on its 

11 primary function, but also on the dependencies between clusters and the infrastructure systems that 

12 support them. These dependencies need to be addressed when setting performance goals to avoid 

13 potential cascading failures of multiple systems. 

14 Cascading failures occur when a failure triggers failures of other components or systems. It can occur 

15 within one system, such as a power grid, when one component failure causes an overload and subsequent 

16 failure of other components in sequence. It can also occur between systems when the failure of one 

17 system causes the failure of other systems. For example, a multiple-hour loss of power in a community 

18 can cause failure in the cell phone system if there is no emergency power to maintain the cell towers.

19 Identifying the dependencies and potential cascading failures is the first step. Reducing the effect of 

20 dependencies and consequences, where possible, and setting performance goals that balance the role of 

21 dependent systems in community recovery is achieved through multiple approaches. For example, 

22 dependencies can be reduced by adding redundancy, increasing capacity, and installing weak links that 

23 constructively isolate portions of a system that do not need to be interconnected. Governance processes 

24 and public policies also play a key role in developing plans for mitigation, response, and recovery 

25 management of dependencies.

26 4.2. Dimensions of Dependency

27 Interactions within and between infrastructure systems are dependent on a number of factors. 

28 Traditionally, dependencies consider the physical and functional relationship between different systems

29 (i.e., drinking water systems require electricity to operate pumps). However, this is only one dimension 

30 that illustrates system interaction. This section presents multiple dimensions of dependency considered in 

31 community resilience planning: internal and external, time, space, and source dependencies. It should be 

32 noted that due to the complex nature of infrastructure system interactions, these dimensions of 

33 dependency are not completely decoupled.

34 4.2.1. Internal and External Dependency

35 Disruption to the normal operating state of the built environment reveals that infrastructure systems are 

36 interconnected through a web of external dependencies. Additionally, within a given system (i.e., an 

37 individual service provider) operations are dependent on a similar web of internal dependencies. Failure 

38 of a single critical system component can result in cascading failures within an individual system, as in 

39 the case of lost electrical power to an estimated 50 million people in the 2003 Northeast Blackout (NERC 

40 2004). External dependencies can also lead to cascading failures of other infrastructure systems, as in the 

41 shutdown of train service in and out of New York City and loss of cell sites after batteries were drained in 

42 the 2003 Northeast Blackout.

43 Internal Dependency

44 Within a given system, there are certain components that are critical to the successful operation of the 

45 system. An example of a critical component in a water system is a pump that delivers water to a water 
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46 tower to distribute onto customers by gravity feed. If the pump stops working, then customers in the 

47 pressure zone served by that pump are without water – unless there is redundancy built into the system to 

48 supply water in another way. This pump example represents an infrastructure-related dependency internal 

49 to a single water utility. The pump would also be an internal dependency that affects operations within a 

50 single infrastructure system if it was part of a system that provided water to numerous water utilities from 

51 a wholesale water supplier. In addition to physical infrastructure-related internal dependencies, each 

52 infrastructure system depends on a number of other factors to sustain normal operations. 

53 An example of infrastructure system interdependencies is shown in Figure 4-1 for emergency services. 

54 The example illustrates the dependencies that may exist between the services and buildings at the 

55 „emergency services‟ level with the other infrastructure systems. Understanding of dependencies and 

56 potential cascading effects provides an informed basis for setting performance goals for community 

57 response and recovery.

58

59 Figure 4-1. Example of Infrastructure Interdependencies for Emergency Services (Pederson et al 

60 2006)

61 External Dependency

62 Infrastructure systems are typically dependent on other external systems for continued successful 

63 operation. The water pump described above is dependent on electrical power for operation; therefore, it is

64 dependent on the energy system that is external to the water system. The pump may be able to operate for 

65 a short period with an emergency generator, but the generator would be dependent on refueling during an 

66 extended power outage. Refueling is in turn dependent on an available supply of fuel and a transportation 

67 system to deliver the fuel. 

68 Figure 4-2 illustrates other examples of dependent relationship among infrastructure systems. These 

69 relationships can be characterized by multiple connections among infrastructure systems. The behavior of 

70 a given infrastructure system may be initially evaluated in isolation from other infrastructure systems, but 

71 community resilience planning requires understanding of the integraated performance of the physical 

72 infrastructure. 
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73

74 Figure 4-2. Example of External Dependency Relationship (Rinaldi et al 2001)

75 Cascading Failures

76 Internal dependency-related cascading failures can affect power transmission, computer networking, 

77 mechanical and structural systems, and communication systems. External dependency-related cascading 

78 failures can affect all buildings and systems. Figure 4-3 and Figure 4-4 illustrate how internal and external 

79 dependencies resulted in cascading failures in the 2003 Northeast Blackout. Failures in physical 

80 infrastructure can also have cascading impacts on social institutions. For example, prolonged loss of 

81 critical services following a disaster may drive small businesses to relocate or go out of business entirely.
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82

83 Figure 4-3: Power System Internal Dependence Cascading Failure in the 2003 Northeast Blackout

84

85

86 Figure 4-4: External Dependence Cascading Failure in the 2003 Northeast Blackout

87 4.2.2. Time Dependency

88 Recovery Phases

89 After a disaster, the time to restore critical services depends on how rapidly an infrastructure system and 

90 other systems required for its functioning can recover. Light-rail transportation systems, such as the Bay 

91 Area Rapid Transit (BART) system in the San Francisco Bay area, require electrical power for operation. 

92 No matter how resilient the light-rail infrastructure system, recovery of service depends on the restoration 

93 of electrical power.
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94 There may also be operational dependencies that impact a utility provider‟s ability to perform repairs. 

95 Crews typically rely on the transportation network (roads and bridges) to access repair sites, liquid fuel 

96 for trucks and equipment, cellular phones for communication, availability of repair supplies through the 

97 supply chain, etc. Disruption in any one or a combination of these systems can increase delays in recovery 

98 of service.

99 The resilience framework defined in Chapter 3 organizes the community resilience plan around three 

100 phases of recovery using four categories of building clusters. The nature of the critical dependency issues 

101 is different for each of these phases. The first phase, focused on immediate response and labeled as 

102 “short-term”, is expected to last for days and requires critical facilities and provisions for emergency 

103 housing. The second, intermediate recovery phase, is expected to last for weeks to months and includes 

104 restoration of housing and neighborhood-level services, such as schools. The third, the long-term recovery 

105 phase, focuses on full recovery of the community‟s economic and social base. Each phase has a unique 

106 set of dependencies, as is introduced below.

107 Short-Term Recovery Phase

108 During the short-term phase (days), the normal operation of infrastructure systems may be impaired. 

109 Individual system operators will activate their emergency response plans. Internal dependencies (such as 

110 staff, operations center, data, repair supplies, etc.) and key external dependencies (such as transportation) 

111 will be critical in defining the pace of the initial response. A well-defined governance process, between 

112 and among government emergency managers and system providers, will be essential to coordinate system 

113 restoration priorities that are best for the community, especially when the recommended restoration 

114 sequence might not be optimal for an individual system provider. A report by the City and County of San 

115 Francisco Lifelines Council indicated that a top planning and preparedness priority for system providers is 

116 to develop communication and employ priority decision-making strategies to aid in post-disaster response

117 (CCSF Lifelines Council 2014).

118 Critical facilities, as defined in Chapter 3, are a small number of building clusters and supporting 

119 infrastructure systems that need to be functional immediately after an event to organize and direct the 

120 emergency response and provide a safe environment for emergency responders. During this early phase, 

121 the degree of dependence on other infrastructure systems depends on their ability to operate with

122 emergency power, an independent communication network, and possibly onsite housing and subsistence 

123 for the staff. Critical transportation routes need to be established prior to the event and made a high 

124 priority in post-event cleanup and debris removal. Critical routes enable replenishment of onsite supplies 

125 including fuel, water, food, medical supplies, etc. Performance goals for recovery need to represent an 

126 appropriate balance between having the needed supplies on hand to operate independently for a short 

127 period and defining achievable restoration times.

128 For example, the stored water at some hospitals can only supply drinking water for three to four days.

129 This supply may only represent about 5% of the total water usage, whereby some hospitals‟ total water 

130 usage may exceed 300,000 gal/day. Many hospitals do not currently have onsite storage capacity for 

131 wastewater and have limited storage capacity for medical waste. These dependencies would likely impair 

132 hospital functionality after a hazard event. In California, the Office of Statewide Health Planning and 

133 Development is implementing requirements to provide three days of an operational supply of water 

134 (including water for drinking, food preparation, sterilization, HVAC cooling towers, etc.), wastewater 

135 storage, and fuel for emergency generators (CBC 2013).

136 The timing of a disaster may also impact the resources available for response. Availability of hospital 

137 beds is often seasonally dependent. During the winter respiratory season, many hospitals operate at or 

138 near capacity, limiting the number of patient beds available for disaster response (even after discharge of 

139 less critical patients and canceling elective procedures).
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140 The need for temporary housing for emergency responders and displaced individuals and animals, as 

141 discussed in Chapter 2, is often met by using schools, shelters, hotels, conference centers, residences that 

142 are safe to shelter-in-place, etc.. Food, water, security, and sanitation needed to protect public health are 

143 usually provided at centralized locations. During the short-term recovery phase, there is a limited need for 

144 transportation, power, and communication. For example, current thinking for earthquake resilience says 

145 that it is best for residents to shelter in their homes, neighborhoods, or within their community. Recovery 

146 performance goals should consider such options.

147 The inability to provide sufficient temporary housing can lead to a mass exodus from the community that 

148 could cascade into a loss of residents and ability to restore the economic base of the community. 

149 Performance goals need to realistically estimate the number of displaced residents and emergency 

150 responders that need to be accommodated, and the availability of adequate facilities within or adjacent to 

151 the community.

152 Intermediate Recovery Phase

153 In the intermediate recovery phase (weeks), the dependency focus is expected to shift more to external 

154 dependencies (electricity, liquid fuel, transportation, etc.) along with key internal dependencies (funding

155 for payroll and repair supplies, contractors, etc.).

156 Restoring fully-functional neighborhoods is key to maintaining the workforce needed to restore the 

157 economic vitality of the community after a hazard event. During this period, special attention must be 

158 paid to the needs of the disadvantaged and at-risk populations who require a higher level of assistance.

159 Functioning residences, schools, and businesses are needed rapidly enough to give the population 

160 confidence to stay and help to support community recovery. If people are unable to shelter in their 

161 neighborhoods, the small neighborhood businesses they depend on will likely lose their client base and

162 have to be relocated or close. This, in turn, may cascade into delays for recovering the community‟s

163 economy. 

164 The needs of commercial services, such as banking, are critical to recovery of a community. If the 

165 primary economic engine of a region is based on a manufacturing plant that requires water, wastewater, 

166 and power operating within two weeks after an expected hazard, then the intermediate recovery phase 

167 must address these dependent systems. The intermediate recovery plans should consider other factors, 

168 such as for parents to return to their jobs, schools and daycare facilities will need to be back in operation.

169 The condition of the built environment that supports residences, neighborhoods, and businesses is one key

170 factor that determines recovery time. Significant structural damage to buildings and infrastructure systems 

171 cannot be repaired within a few weeks; it takes months or longer, depending on the damage. Buildings 

172 need to be safe to use while being repaired for minor damage or temporary facilities will need to be 

173 provided, especially for damaged residences. The transportation, energy, water, wastewater, and 

174 communication systems that support these facilities need to be restored within the same timeframe.

175 Long-Term Recovery Phase

176 In the long-term recovery phase (months), it is anticipated that utility services will be restored (at least 

177 with temporary fixes). If a community is in the early stages of developing its resilience, the recovery time 

178 may take longer due to needed repairs or rebuilding. As a community develops a „mature‟ resilience, a 

179 similar event should cause less damage and have shorter, less costly recovery times. The key 

180 dependencies at this point are related to supplies, equipment, and resource availability for repairs and 

181 reconstruction.

182 Restoring a community after a major event will provide a significant, short-term stimulus to the economy 

183 from the accelerated construction activity and provide an opportunity to improve the built environment 

184 according to a community‟s resilience plan, financed by government, insurance companies, large 

185 businesses, private savings and developers. In order for the recovery process to successfully improve 
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186 community resilience, a governance structure needs to be in place that approves reconstruction rapidly 

187 and in accordance with the community‟s interests. Any stall or stalemate in the decision-making process 

188 will delay the construction activities needed to restart the economy.

189 It is important that communities develop a plan before a disaster on how to manage the logistics of 

190 recovery. For example, logistics include an expedited building permit process and adequate resources for 

191 building inspections during a post-disaster construction boom. They also include land use planning 

192 decisions that will guide rebuilding. If the process is delayed, then people and businesses may move out 

193 of the region and the opportunity to build back a better, more resilient community is lost. The Oregon 

194 Resilience Plan indicated that businesses are only able to accommodate approximately two to four weeks 

195 of business interruption before they would need to relocate or go out of business. This is particularly 

196 troubling to a state like Oregon where a large portion of the economy relies on small businesses and 

197 where the current expected level of resilience for a Cascadia Subduction Zone earthquake does not meet 

198 this four-week time window. Japan experienced small business losses because of delayed decisions in 

199 land use planning to rebuild in the tsunami-impacted region after the 2011 Tohoku earthquake 

200 (Mochizuki 2014).

201 4.2.3. Space Dependency

202 Disaster Impact Region

203 Different types of disasters result in variation in the geographic area of impact. Hurricanes or a Cascadia 

204 Subduction Zone earthquake may impact a large multi-state region, while tornados may only impact a 

205 portion of a community. Communities need to consider the potential geographic area of impact for their 

206 expected hazards as part of the planning process. The Oregon Resilience Plan (OSSPAC 2013) was 

207 developed for a scenario Cascadia Subduction Zone earthquake that would likely impact a region 

208 including Northern California, Oregon, Washington, and British Columbia. The plan discusses a strategy 

209 where the central and eastern portions of the state would provide assistance to the Willamette Valley/I-5 

210 Corridor region (area including the state‟s largest population centers) and then the Willamette Valley/I-5 

211 Corridor would provide assistance to the coastal region. Other mutual aid assistance would likely be 

212 mobilized from Idaho, Montana, and other adjacent states. This is in contrast to a Midwest tornado, which 

213 may cause significant devastation to a particular community, but assistance in response and recovery is 

214 available from the surrounding communities.

215 Location of Critical Infrastructure

216 The physical location of infrastructure within a community impacts how it is expected to perform in a 

217 disaster. For example, wastewater treatment plants are often located close to rivers or the ocean for 

218 system operation reasons, but this makes them particularly vulnerable to flooding, sea level rise, and 

219 tsunami hazards. In the resilience planning process, communities need to consider how the expected 

220 hazard and location of existing infrastructure impacts expected system performance. Communities should

221 also adopt land use planning policies that consider the dependence between physical location and system 

222 performance, when evaluating upgrades to existing facilities, construction of new infrastructure, and 

223 rebuilding after a disaster.

224 Co-location

225 Infrastructure systems are often co-located along transportation or other utility corridors. The close 

226 proximity of these different systems can lead to unintended damage to these co-located systems.

227 Infrastructure system pipelines and conduits are often co-located on bridges at river or other crossings and 

228 can be significantly impacted by earthquake and inundation (flood and tsunami) hazards. Figure 4-5

229 shows an example of where bridge support settlement during the 2011 Christchurch New Zealand 

230 earthquake caused a sewer pipeline, supported by the bridge, to break and spill raw sewage into the river 

231 below. Telecommunications wires are often supported by electrical power poles, so if the pole breaks,

232 both systems are impacted. Water and wastewater pipelines are often co-located near other buried 
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233 infrastructure under or adjacent to roadways. Failure of pipelines may result in damage to the roadway 

234 (i.e. sinkhole from water main break or collapsed sewer pipeline) and impacts to traffic when repairs are 

235 being made. Co-located infrastructure not only results in potential damage to multiple systems, but also 

236 often requires significantly more coordination between service providers during repair. 

237

238

239 Figure 4-5: Example of Infrastructure Co-location (Source: Eidinger & Tang, 2014)

240 4.2.4. Source Dependency

241 Communities depend on goods and services that may or may not be available locally. Disasters that

242 impact the source of these goods and services can have far-reaching downstream impacts.

243 In the Pacific Northwest, Oregon is dependent on refineries in the State of Washington for a supply of 

244 liquid fuel. A Cascadia Subduction Zone earthquake would likely disrupt refinery operation and limit 

245 available liquid fuel supplies in Washington and Oregon. Similarly, a Gulf Coast hurricane could damage 

246 offshore drilling platforms and oil refinery facilities, disrupting the liquid fuel supply for the hurricane247 impacted region and larger portions of the US.

248 Regional utility systems provide another example of source dependency. The Tennessee Valley Authority 

249 (TVA) supplies power to over 150 municipal utility companies and several large industrial users in 

250 Alabama, Kentucky, Mississippi, and Tennessee. A disaster, such as an ice storm, impacting one or more 

251 TVA power generation facilities or transmission lines, has the potential to disrupt electricity over a large 

252 geographic area.

253 A disaster, such as a wildfire, can impact the drinking water supply due to high post-fire sediment loads.

254 These sediment loads can cause damage to reservoirs and treatment plants that result in higher treatment 

255 costs to remove suspended solids from drinking water. The impact of sediment is highest in the burned 

256 area, but data from the Southern California wildfires in the fall of 2003 indicated increased sediment 

257 loads at treatment plants up to 100 miles from the fire (Meixner and Wohlgemuth 2004).

258 4.3. Planning for Infrastructure System Dependencies 

259 As part of the community resilience planning process, utility providers, businesses, and others should be 

260 encouraged to refresh or develop their own emergency and continuity of operations plans and identify 

261 internal dependencies. As organizations are conducting internal resilience planning activities, they should 

262 also compile a list of external dependencies and they impact their operations. After each infrastructure 

263 system identifies their external dependencies, the next step is to engage all infrastructure systems along 

264 with community and business leaders to discuss the current expected performance of infrastructure for the 
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265 range of disasters expected, external dependencies, and expected service restoration times for each 

266 infrastructure system. 

267 It is critical that all stakeholders are in these discussions, including elected officials, emergency managers, 

268 first responders, service providers, business leaders, civic organizations, and disaster services 

269 organizations, etc. For discussion of external dependencies, the definition of community might need to be 

270 broadened, as utilities often serve a larger area than just one local population.

271 Understanding the dependencies within and between physical infrastructure systems is a new and 

272 developing area of planning related to resilience and recovery from significant disruptions. However, 

273 there is an immediate need for a process to identify the interdependencies for a resilience framework and 

274 an empirical method based on historical data seems to be the most achievable at this point. Such a method 

275 was used by the City and County of San Francisco Lifelines Council in 2013 and it can be applied to 

276 other communities. San Francisco reported their findings and recommendations in February 2014 (CCSF 

277 Lifelines Council 2014). Their process followed these steps:

278 1. Form a service provider council of private and public infrastructure owners and provide a 

279 quarterly forum for them to meet, share current planning activities, and discuss response and 

280 recovery issues, their interdependencies, and methods to improve the existing conditions.

281 2. For the extreme level of all prevailing hazards, characterize the expected level of damage in terms 

282 related to infrastructure system performance from the view of the infrastructure provider. Figure 

283 4-6 illustrates the restoration times estimated by the providers in the San Francisco study.

284 3. For each infrastructure system, document the planned response and restoration process, likely 

285 dependencies on other systems, and the understanding of other system dependencies on them. 

286 4. Process the information and determine overall interactions between systems and the related 

287 dependencies. Identify areas with potential for cascading effects, occurrences of co-location, 

288 overlaps, and hindrances related to restoration and recovery plans. Table 4-1 illustrates the 

289 dependencies identified in the San Francisco Study.

290 5. Develop a series of recommendations related to the next steps needed to better define the needs, 

291 advance collaborative planning where needed, prioritize the needed mitigation projects and 

292 identify funding sources for pre- and post-event needs.

293

294 Figure 4-6: Potential Service Restoration Timeframes following a Scenario M 7.9 Earthquake on the 

295 San Andreas Fault. (CCSF Lifelines Council, 2014)
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296 Table 4-1: Infrastructure System Dependencies following a scenario M7.9 earthquake on the San Andreas Fault. (CCSF Lifelines Council,

297 2014)

The overall interaction and dependency on a particular system (read down each column)

Regional 

Roads City Streets Electric Power Natural Gas Telecom Water Auxiliary Water

WasteWater Transit Port Airport Fuel

Infrastructure System 

Operators‟ dependency on other Infrastructure systems 

(read across each row) 

Regional 

Roads General Restoration 

Substitute Restoration Restoration Restoration Restoration Restoration Substitute Restoration Restoration

City 

Streets

Substitute 

Restoration General Co-location, Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration Restoration

Electric 

Power Restoration Co-location, 

Restoration General Restoration Co-location, Restoration

Co-location, 

Restoration

Co-location, 

Restoration Co-location Restoration Restoration

Natural 

Gas Restoration

Functional, 

Co-location, 

Restoration

Substitute General Restoration Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration Co-location Restoration Restoration

Telecom Restoration Co-location, 

Restoration

Functional, 

Restoration Restoration General Co-location, Restoration

Co-location, 

Restoration

Co-location, 

Restoration Restoration Restoration

Water Restoration Restoration Restoration Restoration General Co-location Restoration

Auxiliary 

Water Restoration

Functional, 

Restoration Restoration Restoration Functional, 

Restoration

General Co-location, 

Restoration Restoration

WasteWater Restoration

Co-location, 

Restoration

Functional, 

Restoration Restoration Functional, 

Restoration

General Co-location, 

Restoration

Restoration

Transit Substitute, 

Restoration

Functional, 

Substitute,

Co-location, 

Restoration

Functional, 

Restoration Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

General

Co-location, 

Restoration

Functional, 

Restoration

Port Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration

Co-location, 

Restoration Co-location Co-location Co-location General Restoration

Airport Restoration Restoration Restoration Restoration Restoration Co-location, 

Restoration General Functional, Restoration

Fuel Restoration Restoration Functional, 

Restoration Restoration Restoration Restoration Restoration General

298

Legend: Key to terms used in the matrix:

Significant interaction and dependency on this infrastructure 

system for service delivery and restoration efforts

Functional disaster propagation and cascading interactions from one system to another due to interdependence

Co-location interaction, physical disaster propagation among infrastructure systems

Moderate interaction and dependency on this infrastructure 

system for service delivery and restoration efforts

Restoration interaction, various hindrances in the restoration and recovery stages

Substitute interaction, one system‟s disruption influences dependencies on alternative systems

Limited interaction and dependency on this infrastructure system 

for service delivery and restoration efforts

General interaction between components of the same system. (All systems would have general interaction issues, but 

some issues are more crucial for the system‟s potential disruption and restoration.)
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299 Figure 4-7 shows a map of Portland, Oregon with a GIS overlay of infrastructure systems that are

300 contained in the Earthquake Response Appendix to the City‟s Basic Emergency Operations Plan (City of 

301 Portland 2012). The city used this information to coordinate the potential spatial dependencies of the 

302 city‟s infrastructure. Eventually these tools may include systems modeling functionality that could enable 

303 scenario-based assessment of infrastructure system depencencies or be used as a tool to prioritize post304 disaster infrastructure repairs and optomize restoration of all infrastructure systems. 

305

306

307 Figure 4-7: GIS Map of Infrastructure Systems around Portland, Oregon (City of Portland, 2012)

308 4.4. References

309 Rinaldi, S.M., J.P. Peerenboom, and T.K. Kelly (2001) Identifying, Understanding, and Analyzing 

310 Critical Infrastructure Interdependencies, IEEE Control Systems Magazine, December

311 CBC (2013). California Building Code. California Building Standards Commission, Sacramento, CA.

312 CCSF Lifelines Council (2014). Lifelines Interdependency Study/Report. San Francisco, CA: City and 

313 County of San Francisco Lifelines Council.

314 City of Portland (2012). City of Portland Basic Emergency Operations Plan, Earthquake Response 

315 Appendix. Portland, OR.

316 Eidinger, J., and Tang, A. (2014). Christchurch, New Zealand Earthqake Sequence of Mw 7.1 September 

317 04, 2010 Mw 6.3 February 22, 2011 Mw 6.0 June 13, 2011: Lifeline Performance. Reston, VA: 

318 American Society of Civil Engineers.
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319 Pederson, P., D. Dudenhoeffer, S. Hartley, and M. Permann (2006) Critical Infrastructure 

320 Interdependency Modeling: A Survey of U.S. and International Research, INL/EXT-06-11464, 

321 Idaho National Laboratory.

322 Mexiner, T., and Wohlgemuth, P. (2004). Wildfire Impacts on Water Quality. Southwest Hydrology, 

323 September/October.

324 Mochizuki, J. (2014). Decision-Making, Policy Choices and Community Rebuilding after the Tohoku 

325 Disaster. Journal of Integrated Disaster Risk Management, 4 (2): 11-26.

326 NERC (2004). Technical Analysis of the August 14, 2003, Blackout: What Happened, Why, and What 

327 Did We Learn?. Princeton, NJ: North American Electric Reliability Council.

328 OSSPAC (2013). The Oregon Resilience Plan, Reducing Risk and Improving Recovery for the Next 

329 Cascadia Earthquake and Tsunami. Salem, OR: Oregon Seismic Safety Policy Advisory 

330 Commission.