Damage of gas facilities by Great Hanshin earthquake and restoration process

The Great Hanshin Earthquake caused major damage to urban infrastructure and lifelines. In gas supply facilities and equipment, most of the damage occurred in low-pressure pipelines that used screw joints. To prevent secondary disaster, Osaka Gas suspended gas supply to about 860,000 households by designating earthquake isolation blocks in which the damage was most severe. The restoration work was conducted under a difficult work environment due to such factors as large amounts of water and sand inside the gas pipes, but work was completed on the 85th day (April 11) from the day of the earthquake.(AU)

Pipeline replacement feasibility study : A methodology for minimizing seismic and corrosion risks to underground natural gas pipelines

This report completes the review of procedures used by the Southern California Gas Company to optimize decisions on pipeline replacement and repair. In addition to discussions with the Engineering Design Department, meetings were also held with representatives from System Planing, Transmission and Distribution. This study was conducted as a joint effort between EQE International and Cornell University. Partial support for this effort was received from the National Center for Earthquake Engineering Research. This report is comprised of two major parts: (1) a report that discusses a plan for consideration of seismic and corrosion risk under a common program, and (2) a report that summarizes the development of improved corrosion leakage models for the Southern California Gas Company (Appendix B).(AU)

Feasibility study of replacement procedures and earthquake perfomance related to gas transmission pipelines

A detailed and systematic review of the seismic perfomance of gas transmission lines prior to the 1994 Northridge earthquake shows that all repairs in pipelines affected by traveling ground waves occurred in areas which experienced seismic intensities of MMI>/ VIII. A review of gas transmission line perfomance during the 1994 Northridge earthquake discloses a similar pattern of seismic response. Approximately 91

of all pipeline damage caused by traveling ground waves in the 1994 event occurred in areas with MMI>/VIII. The earthquake-related damage has been predominantly in the form of ruptures at oxy-acetylene girth welds. The potential for damage in such welds appears to increase considerably for seismic intensities equal to and greater than MM VIII.(AU)

Systems analysis for Memphis light, gas and water

In this study, a coordinates systems approach was used to examine the overall seismic perfomance of MLGW's lifeline systems. The study examined: seismic hazard and ground motion characteristics of the area; geotechnical features, with a special emphasis on liquefaction and resulting lateral spread; the effect of ground motion and geotechnical features on the seismic perfomance of mechanical and structural components including pipelines, storage tanks, pumping stations, treatment facilities, etc., measured in terms of fragility quantities; reliability and interactive nature of system functionality under severe seismic conditions with the aid of Monte Carlo techniques utilizing component fragility information; and the socioeconomic impact arising from system failure.(AU)

The Northridge, California earthquake of january 17, 1994 : Perfomance of gas transmission pipelines

On January 17,. 1994 at 4:31 a.m., a magnitude 6.6 earthquake struck the Los Angeles metropolitan area. Epicentered in the San Fernando Valley town of Northridge, California, the earthquake caused serious damage to buildings and sections of elevated freeways; ignited at least one hundred fires as it ruptured gas pipelines; and disrupted water supply systems. As a consequence, 57 people died, another 1,500 were seriously injured, and 22,000 were left homeless. Over 3,000 buildings, most of which were residential structures, were declared unsafe for reentry due to earthquake damage. Los Angeles, a city which has extensively prepared itself for earthquakes, found that it had experienced the most destructive event since the 1906 San Francisco earthquake. Direct economic losses are estimated currently at over $20 billion. This reconnaissance report provides a perfomance analysis of gas transmission lines, both during this earthquake and during previous earthquakes, in Southern California.(AU)

Assessing vulnerability of BC GAS pipelines to lateral spread hazards

A systematic review of seismic risks was perfomed for the BC GAS Lower Mainland natural gas transmission system using a probabilistic approach to define potential earthquake hazards and pipeline response. Potentially liquefiable deposits were identified and mapped into a Geographical Information System (GIS). Lateral spread displacements were made based on the methodology of Bartlett and Youd. There are two very unique features of the BC GAS study. First, finite element anlyses were used to define pipeline vulnerability. Second, published data on lateral spread displacements were used to estimate the likelihood of lateral spreading at specific pipeline locations. This study highlights research needs to define lateral spread hazard and is believed to be a model for future seismic risk studies of pipeline systems.(AU)

Estimation of indirect losses caused by disruption of lifeline service : A pilot study of the Memphis light, gas and water system

A general methodology for estimating the indirect losses caused by a disruption of lifeline service is presented. This methodology is different from previous approaches in that it attempts to incorporate local data on lifeline usage patterns and detailed information on regional economics into the analysis. Although the analysis is presented using natural gas as the pilot system, the methodology is general enough to have application for other lifeline systems. Since the conduct of this study is part of a large National Center for Earthquake Engineering Research (NCEER) effort that involves multiple investigators, parts of the analysis are still being perfomed. Therefore, what is presented in this paper is a snapshot of the analysis with particular focus on model development. Models for natural gas usage, economic productivity and natural gas outage are presented. In order to provide the reader with some understanding of how the results of the analysis will feed into the overall loss assessment procedure, a general discussion of the methodology is presented along with a discussion of future activities. This study is part of the Urban Seismic Risk Project that is being sponsored in whole by the NCEER.(AU)

Earthquake perfomance of gas transmission pipelines

Over 61 years of earthquake perfomance of steel transmission pipelines operated by the Southrn California Gas Company are reviewed. The seismic record includes 11 major earthquakes with ML >= 5.8 and epicenters within the transmission system. An evaluation is made of the most vulnerable types of piping, failure mechanisms, break statistics, threshold seismic intensity to cause failure, and damage induced by permanent ground displacement. The database assembled represents one of the most comprehensive and detailed records of seismic response in a large, complex gas transmission system.(AU)

A simplified model for assessing secondary loss impacts associated with oil and natural gas pipeline failures during earthquakes

This paper discusses the results of a preliminary study to estimate the secondary and regional impact of oil and natural gas system disruption during earthquakes. Simplified models have been developed which approximate order-of-magnitude secondary losses. In this study, secondary loss is defined as business interruption costs. To demonstrate the methodology, the models are applied to the New Madrid Seismic Zone. A comparison of the present results with those published in a recent Applied Technology Council report (ATC-25) indicate that the simplified models provide a reasonable approximation of business interruption losses associated with the disruption of oil and natural gas supply. This methodology can be used in cases where little or no data exists on the locations of critical lifeline systems, or where rapid evaluations of business interruption losses are needed. The results presented here represent findings from a previous Federal Emergency Management Agency (FEMA) study and an ongoing study for the National Center for Earthquake Engineering Research (NCEER).(AU)

Technological disasters and environmental risk acceptance in Mexico City : The San Juanico gas explosion case

The metropolitan area of Mexico City is the greatest human settlement in the world with nearly 19 million inhabitants in 1987. Its urban growth has caused industries to establish within and around the city, thus increasing the risk to nearby communities. In one of these communities, known as San Juanico, a gas plant explosion occures in 1984 incurring enormous economic and social costs. One year after the disaster, a study was conducted in which 100 families living within a one kilometre radius of the explosion center were handed a questionnaire which covered sociodemographic aspects, the impact on the family in terms of human and property losses, perception of the possibility of another disaster, attribution of the causes of the disaster, and attidudes and actions in the high risk situation. The results show that in the aftermath of a disaster, people perceive their habitat as risky and believe that another disaster may occur. Even though many of them regard moving away as a means of lessening the risk, very few of them (3

) are really doing anything about it. The results are discussed in terms of principles of risk acceptance and the need to study the phenomena within a socio-cultural context.(AU)

The breakdown of a emergency system following a gas explosion in Osaka and the subsequent resolution of problems

Osaka, a modern urban metropolis in Japan, experienced a tragic gas explosion in 1970 when the dispatch room of the City Fire Department was in the process of being moved to a new building. Many unforseen problems arose during this disaster: eg, there was an overall lack off leadership, confusion of communication, a need for triaged, and lack of control of mass media. The Osaka Medical Association organized a committee to resolve these problems. Their conclusions and recommendations were that a control headquarters be established at the scene of disaster, the number of ambulances and EMTs be increased, disaster tags be utilized, a special radio frequency be created, and a computeraided command and control system for fire fighting and ambulance services be introduced. These recomendations have all been followed