Crude Oil Transmission Study
An Assessment of the Social, Economic and Environmental Impacts Resulting from Oil Spillage and Disruption Caused by A Major Earthquake in the New Madrid Seismic Zone
Objective and Approach
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In 1989, the National Center for Earthquake Engineering Research launched a multi-year,
multi-disciplinary study of the seismic vulnerability of an important lifeline system. The
production and delivery of crude oil is critical to every major industry and business
sector in the United States. This nation's most crucial crude oil system traverses the
midwest and is subject to seismic hazards posed by the New Madrid Seismic Zone (NMSZ). To
understand fully the significance of this system, particularly after major disasters such
as earthquakes, it is necessary to quantify the level of seismic vulnerability of this
system and the impact that may result should oil be released or disrupted. To address
these questions, NCEER formed a multi-disciplinary team representing researchers in
seismic hazard assessment, component vulnerability analysis, system reliability analysis,
and socioeconomic impact analysis.
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This study had three major objectives. First, the seismic hazard potential in the midwest required quantification. Recent seismicity data suggest that the likelihood of a magnitude 7.6 earthquake in the New Madrid region is approximately 7% by the year 2000 [Johnston and Nava, 1985]. Second, the seismic vulnerability of oil pipeline systems had to be evaluated. Vulnerability models were developed for underground pipelines and aboveground facilities to determine the likelihood of failure or damage during an earthquake. Finally, based on the seismic vulnerability of these systems, the indirect impacts caused by failure and disruption of this system were assessed.
The research plan called for investigations that focused on the following areas: quantification of seismic hazard potential, with emphasis on liquefaction hazards; seismic vulnerability modeling of underground pipelines; seismic vulnerability modeling of other oil pipeline system components, such as pump stations; system reliability analysis; environmental impact analysis; indirect economic loss analysis; and organizational and institutional response analysis to address the issues related to energy supply and distribution.
This research task is part of NCEER's Lifeline Project. Task numbers are
87-3013, 88-3005, 88-3006, 88-3007, 88-3011, 88-3013, 88-4003, 89-3007, 89-3012, 89-4003,
90-3007 and 90-4003.
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The contributions from this study have been numerous. Perhaps, the most significant achievement is that a multidisciplinary research team was assembled to address a complex engineering and socioeconomic problem. Past efforts to address lifeline problems have only been marginally successful in quantifying the effects caused by lifeline failure. The reason for this limited success has been that expertise beyond that readily available within the engineering community must be applied. Also, to fully assess the nature of this problem, multi-year efforts are required. Only in a few cases, are extended research efforts granted to investigate these multi-dimensional problems.
Some of the more important conclusions that have resulted from this study are listed below.
It is difficult to generalize system reliabilities for linear pipeline systems, such as oil delivery pipelines, because damage or failure of one or several components can disrupt the entire serviceability of that system.
Earthquake-induced pipeline failures will generate a range of direct and indirect social and economic effects in both the short and the longer term.
The costs associated with the repair of a damaged oil pipeline system represent only a small percentage of the cost associated with its failure. Environmental damage, business interruption and regional economic losses caused by disruption of oil accounts for over 90 percent of the losses associated with these pipelines.
The Midwest lacks the resources necessary to manage major earthquake-induced oil spills.
An examination of the infiltration, distribution and dissolution from hydrocarbon spills indicates that this process is slow, which would allow ample time for remediation should such a spill occur. However, the remediation effort must be complete to ensure that no health hazard exists.
The following sections discuss in more detail the research conducted by NCEER investigators that support the major conclusions provided above.
O'Rourke and others (1992) demonstrate the complexity in assessing the seismic vulnerability of lifeline systems. While previous studies have addressed issues of seismic vulnerability or reliability, they generally have analyzed the problem solely on the basis of ground shaking, i.e., ground failure hazards, such as liquefaction, have been addressed only qualitatively. One of the main contributions of the current research is that it attempts to quantify the impact of ground failures (i.e., liquefaction and slope movement) on oil pipeline components by estimating the amount and direction of ground movement and their impact on component failure. Utilizing techniques developed by Youd and others (1989), the NCEER team quantified the amount of displacement expected from a large New Madrid earthquake and mapped this information onto critical oil pipelines in the midwest. Based on the orientation of the pipeline relative to these displacements, different probabilities of pipe failure were computed accounting for lateral and longitudinal spreading.
One interesting product that has resulted from this research has been a comparison of the Modified Mercalli intensity scale with the Liquefaction Severity Index (LSI) developed by Youd et al. (1989). Table 1 shows the estimated correlation between these two damage indices for the 1811-1812 New Madrid scenario. This table represents a significant improvement over past methods of characterizing the effects of liquefaction.
|Modified Mercalli Intensity||Damage Desription||Estimated LSI (inches)|
|VIII||Ejected sand and mud in small amounts||10-20|
|IX||Cracked ground conspicuous; underground
pipes sometimes broken
|X||Cracked ground, especially when loose and
wet, up to widths of several inches; fissures
up to canal and stream banks... Landslides
considerable from river banks and steep coasts,
... bent railroads, rails slightly ...tore apart ...
crushed ... pipelines buried in earth.
|Table 1. Estimated Correlation Between MMI and LSI for the 1811-1812 New Madrid Earthquakes [O'Rourke et al., 1992].|
By using a more quantitative scale for measuring the effects of liquefaction, more refined seismic vulnerability models can be applied.
Another major improvement resulting from this research was the application of geographical information system (GIS) methods to pipeline analysis. In this study, three key pipeline systems were analyzed for their seismic vulnerability during a large New Madrid earthquake. These pipelines are shown in figure 1. Based on data collected by the research team, GIS methods were used to quantify the number of miles crossed by each pipeline system in different MMI and LSI zones. This information was used in combination with analytical seismic vulnerability models to estimate the number of pipeline breaks or leaks expected in The New Madrid event. Based on the number of these failures, failure probabilities were computed for each segment of pipeline.
The reliabilities that were computed for each pipeline are given in table 2. As seen in this table, the impact of shaking versus lateral spread effects varies significantly for each pipeline. Also, the reliabilities associated with particular pump stations and pipeline segments for each different pipeline system vary significantly. As a result of these sensitivities, it was concluded that for linear systems such as crude oil pipelines, it is difficult to generalize system performance, since failure of one or more components could lead to system shutdown. In more highly netted systems, such as water distribution or natural gas distribution, the failure of any single component will have less impact on the overall performance of the system. Redundancy plays a signif1cant role in maximizing the reliability (i.e., probability of connectivity) in these more highly netted systems.
|Shaking||Lateral Spread||Landslide||Lateral Spread|
|Table 2. Reliability of Pipeline by Hazard for Recurrence of 1811-1812 Events [O'Rourke et al., 1992].|
In an initial effort to identify the potential consequences of earthquake-induced oil pipeline failures, the Disaster Research Center (Tierney, 1992) undertook an extensive literature review. Among the topics examined were oil spill prevention and preparedness, the economic costs of oil spills, ecological and health effects, oil spill cleanup methods and their effectiveness, and governmental and industry policies and regulations related to oil spill management. Although the literature on earthquake-induced oil spills and their consequences was very sparse, and most of that work focused on areas other than the New Madrid region, many of the materials that were reviewed contained data and information that have implications for estimation of spill-related impacts in the central U.S.
The review concluded that the costs associated with pipeline failures and resultant oil
spills are likely to depend on a number of factors, including: the extent of damage to the
crude oil distribution system; the locations at which the damage occurs; the extent of
damage to the disaster response system and its supporting infrastructure; local and
regional capacity to contain damage and restore service; situational contingencies, such
as the time of year the event occurs and the extent to which secondary hazards, such as
fire, become a problem; and the duration of system disruption. The literature indicates
that spills like those that could occur following a New Madrid event are likely to produce
a variety of direct and indirect social and economic effects. These can be classified into
two categories: effects related directly to oil spills, such as loss of oil and threats to
the water supply; and containment and cleanup and the costs associated with repairing the
system. While many of these effects will be felt in the short term, others will continue
over time. Table 3 summarizes the nature and
duration of these impacts.
The failure of lifeline systems in natural disasters can be devastating, hampering both response and recovery. Recent events, such as the 1989 Loma Prieta and 1994 Northridge earthquakes, have demonstrated that indirect impacts associated with the failure of lifeline systems may far outweigh the direct costs associated with system repair. As a result, the problem of quantifying possible indirect losses is currently receiving increased attention.
In order to address these indirect effects, EQE International developed methods of quantifying indirect or secondary losses associated with oil pipeline failure or disruption. In these studies, indirect loss included business interruption losses, environmental damage caused by oil spillage, and regional economic losses associated with a disruption of oil.
One part of the EQE study focused on losses associated with the remediation of areas affected by oil spillage or leakage (Pelmulder and Eguchi, 1991). This methodology assumed that the same damage assessment techniques described in the previous sections could be used to identify the probable locations of these spills. Then, based on the amount of oil contained within the pipeline system, and other factors such as topography and pipeline size, EQE estimated the amount of oil released to the environment. Depending upon the soil and groundwater characteristics surrounding these spillage sites, different cost models were used to predict the extent of contamination and the remediation cost associated with its cleanup. Finally, these costs were compared to the repair costs for the pipeline.
Figures 2 and 3 show two frequency of exceedance curves for total spill volume and dollar loss, respectively. The range of spilled volumes during the NMSZ simulation was 150,000 to 2,350,000 barrels, with an average spill volume of 400,000 barrels. The 400,000 barrels represent the sum of spill volumes from all leaks during this hypothetical event. The average spill volume expected at a single site was calculated to be 4,700 barrels. Because this is an extreme earthquake event (M8+ New Madrid event), at least one leak occurs in every simulation of the event. The maximum frequency (i.e., the frequency with which at least one leak occurs) is equal to the probability of this event occurring by the year 2000, i.e., 0.005%
Possible dollar losses associated with this cleanup range from 30 million to 2.4 billion dollars. The large range of costs may be attributed, in part, to the significant difference between remediation costs for surface water and soil. When a large number of leaks occur in a simulation, many are in flood plains or on rivers, where there are high cleanup costs. Many more moderate cases are possible, however, and the average loss is expected to be $310 million. The expected loss at a single site is $3.6 million.
In addition to environmental losses, other higher-order economic losses are possible in a large New Madrid earthquake. Table 4 lists some of these higher-order losses and the parameters that influence their levels (Eguchi et al., 1993; Wiggins, 1994).
As part of the crude oil study, the EQE team assessed environmental, refinery/petroleum, and local and regional economic losses from a M8+ earthquake in the New Madrid Seismic Zone. These losses are shown in table 5. The basic conclusion resulting from this study is that repair costs are but a fraction of the total loss associated with the failure and disruption of these oil pipeline systems. In table 5, repair costs account for approximately 2.3 percent of the losses contained in the table. The largest loss will probably be associated with local and regional economies that will suffer because of a disruption of oil. Contingency factors, such as alternative supplies however, have not been factored into the analysis. Nevertheless, disruption of oil supply will have a significant regional impact in the postulated NMSZ event.
Responding to oil spills in a timely manner is an important factor in reducing the social disruption and losses that result from these events. A1though legislation provides for national and regional-level responses in major oil spills, local and state emergency response capability also plays a critical role in oil spill containment. Negative social and economic impacts will invariably be larger when agencies responsible for initial spill management are not able to respond effectively.
Research by NCEER investigators (Tierney and Dahlhamer, 1993) indicates that the highest risk of an earthquake-generated spill is associated with the 40-inch Capline pipeline system, operated by Shell Corporation. Investigators singled out as particularly vulnerable several river-crossing areas in western Tennessee where earthquake-induced pipeline failures are likely due to the potential for soil liquefaction. Based on these research findings, field work was undertaken by the Disaster Research Center to determine the extent to which emergency management and response agencies in the vulnerable area were aware of the hazard and to assess their response capability. To address these issues, face-to-face interviews were conducted with local government and emergency officials in three high-risk counties in western Tennessee, as well as with representatives of four state emergency management, environmental protection, and regulatory agencies.
Analysis of the interview data and documentary materials that were collected during the field study indicate that (1) less than one-third of the local officials and emergency responders interviewed were even aware that a major crude oil pipeline passes through their communities; (2) few responders had considered the possibility that a New Madrid earthquake could cause a crude oil release; (3) local communities lacked resources for managing an oil spill, should one occur; (4) although general earthquake preparedness measures had been undertaken in the three-county area, largely as a result of the Iben Browning prediction of 1991, those efforts were quite modest; (5) virtually no linkages currently exist between the pipeline operator and either state and local officials that could be used as a basis for either emergency planning and response; (6) the resources that were available locally for managing disasters were insufficient, making it difficult to maintain an adequate level of basic earthquake preparedness and effectively ruling out planning for the control of secondary hazards such as oil spills; and (7) although earthquake preparedness was a high priority for the state emergency management agency, it had not planned for possible earthquake-induced pipeline failures, nor had it encouraged local officials to do so.
The study indicates that local and state officials did not recognize pipeline failures and crude oil spills as problems that could occur following a major earthquake. The first step in managing a hazard is to recognize it, and even this elementary recognition is lacking with respect to the oil spill problem. Further, there are few interorganizational linkages that could be activated should such an emergency occur, and the local communities that are most vulnerable lack resources to manage oil spills. As a consequence, it is highly unlikely that oil spills resulting from pipeline failures will be contained, or that early remedial actions will be undertaken. This information provides a context for developing and interpreting loss estimates for the New Madrid Seismic Zone.
This NCEER study was undertaken by the Center for Earthquake Research and Information at Memphis State University (Helweg and Hwang, 1993) to determine the effect of an oil spill, which might be caused by an earthquake rupturing a crude oil pipeline that crosses the recharge area of the Memphis Sands Aquifer. To do this, two numerical models were used to simulate a potential rupture to the 40-inch crude oil pipeline located in Wolf River fluvial valley. This area is suscentible to liquefaction-induced ground failure. The spilled oil could have detrimental effects on the ground water quality, especially impacting the Memphis Sands Aquifer.
The simulation approach used two two-dimensional upstream weighted finite element models to predict the three-dimensional flow phenomenon of released crude in the unsaturated and saturated zones. ARMOS (Areal Multiphase Organic Simulator) was used to simulate the crude oil migration horizontally and to evaluate the extent of the crude dispersion on the ground water table. MOFAT (Multiphase Organic Flow And Transport) was used to simulate crude oil saturation in the vertical flow domain, in order to evaluate the dissolution of particular monoaromatic hydrocarbon isomers such as Benzene, Toluene, Ethylbenzene and Xylene (BTEX) in the ground water system.
The simulated results aided in designing an appropriate strategy for site remediation.
ARMOS predicted a plume covering an area of about 10,800 square meters after 10 days of
migration. The plume covered a maximum area of about 18,800 square meters after 30 days of
migration. MOFAT predicted the most soluble species, toluene, dispensing with the highest
phase concentration of 0.20 kilogram per cubic meters at distances of 56, 79, 102 and 130
meters away from the spill site over the periods of 30, 60, 90 and 120 days of
redistribution. The results show that although significant contamination of local aquifers
is possible, the rate at which this contamination occurs may be slow. This should allow
for ample time for remediation should a spill occur. However, the remediation effort must
be complete to ensure that no health hazard exists.
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Eguchi, R.T., Seligson, H.A., and Wiggins, J.H., "Estimation of Secondary Losses Associated with Lifeline Disruption," Proceedings, 40th North American Meetings of the Regional Science Association International, Houston, Texas, November 11-14, 1993.
Helwig, O.J. and Hwang, H.H.M., "Effects of Hydrocarbon Spills from an Oil Pipeline Break on Ground Water," Technical Report NCEER-93-0012, National Center for Earthquake Engineering Research, University at Buffalo, August 3, 1993.
Johnston, A.C. and Nava, SJ., "Recurrence Rates and Probability Estimates for the New Madrid Seismic Zone," Tennessee Earthquake Information Center, Earthquake Education Project, Memphis State University, Memphis, Tennessee, 1985.
O'Rourke, M., Shinozuka, M., Ariman, T., Dobry, R., Grigoriu, M., Kozin, F., and O'Rourke, T.D., "Pilot Study of Crude Oil Transmission System Seismic Vulnerability in the Central U.S.," Earthquake Spectra, Vol. 8, Number 3, 1992.
Pelmulder, S.D. and Eguchi, R.T., "Regional Risk Assessment of Environmental Contamination from Oil Pipelines," Lifeline Earthquake Engineering, Technical Council on Lifeline Earthquake Engineering, ASCE. Monograph No. 4, August 1991.
Tierney, K.J., "Literature Review on Socioeconomic Impacts: NCEER Pipeline Study," Newark, Delaware, Disaster Research Center, University of Delaware, 1992.
Tierney, K.J. and Dahlhamer, J.M., "Preparedness for Earthquake-generated Crude Oil Spills Among Emergency Management Agencies in High-Risk Areas in Western Tennessee," Newark, Delaware, Disaster Research Center, University of Delaware. 1995.
Turner, W.G. and Youd, T.L., "National Map of Earthquake Hazard," Final Report to the USGS of Grant No. 14-08-001-G1187, Dept. of Civil Engineering, Brigham Young University, 1987
Wiggins, J.H.,"Estimating Economic Losses Due to an Interruption in Crude Oil Deliveries Following an Earthquake in the New Madrid Seismic Zone," Proceedings, Fifth U.S. National Conference on Earthquake Engineering, EERI, Chicago, Illinois, July 10-14. 1994
Youd, T.L., Perkins, D.M., and Turner, WG., "Liquefaction Severity Index
Attenuation for the Eastern United States," Proceedings, Second U.S.-Japan
Workshop on Liquefaction, Large Ground Deformation and Their Effects on Lifelines,
NCEER-89-0032, NCEER, Buffalo, New York, 1989
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