PERSPECTIVE ON THE NORTHRIDGE EARTHQUAKE : Our Lifelines Are Also Our Achilles’ Heels : Besides buildings, we must protect electricity, telecommunications, transportation and water and sewer systems.

The built environment for a city like Los Angeles can be divided into two categories: the buildings in which we live and work and those utilities, services and facilities that enable us to educate our children, increase productivity, protect ourselves against disease, live in peace and enjoy an unparalleled standard of living.

This second category, the civil infrastructure, can be further divided into public buildings and five lifelines: electric power, gas and liquid fuels, telecommunications, transportation and water and sewer systems. These provide the foundation on which modern society has built its wealth and quality of life.

Since World War II, the United States has invested heavily in its infrastructure and has developed some of the most sophisticated lifelines in the world. Most of our food, shelter, health care, commerce and defense depends on an intricate network of interdependent lifelines. It has been said that lifelines are both the lubricant that speeds a society’s development and the glue that binds us together. But for whatever reason, their existence is almost always taken for granted and their availability at minimal cost is considered to be the right of every citizen. Yet they are surprisingly fragile.

At 4:31 a.m. last Monday, a moderate-sized earthquake in the San Fernando Valley paralyzed portions of one of the world’s largest cities. Electric supply was lost, bridges collapsed, major freeways were closed, water mains and gas lines ruptured, fires broke out, dams and reservoirs were damaged and a train loaded with toxic materials overturned. Los Angeles, a city that lives on the edge, awoke to find itself on the brink of a major disaster. Fortunately, few people were on the streets at the time, but reconstruction will take many years. For some people, the emotional scars and financial impact will last a lifetime.

History repeats itself in surprising ways. The 1971 earthquake at Sylmar in the San Fernando Valley was of similar magnitude, and it too played havoc with our lifelines. In fact, the damage sustained in 1971 drew national attention to the importance and fragility of these systems.

The Technical Council for Lifeline Earthquake Engineering was formed soon afterward by the American Society of Civil Engineers, with the object of improving the performance of lifelines in earthquakes. But progress has been hampered by the very nature of lifelines, their interdependence and the conflicting interests of the many owners with jurisdiction over these systems.

Lifelines have been largely neglected by the research community since they have not been perceived to be as important as buildings when mitigating the loss of life and protecting property. Funding agencies have also been slow to recognize the importance of lifeline research and the development of design criteria. This situation has improved slightly in recent years, but with the exception of highway bridges, there are still no federal or state codes for the seismic design of lifelines.

Some owners of large utilities in Southern California have developed their own standards, and they are to be commended for this action. But this voluntary effort is fragmentary at best and inadequate to the public interest. This is because most lifelines are linear systems with little redundancy and are only as robust as their weakest link. All elements of the system and all interdependent systems need to be designed to the same set of seismic criteria to assure their continued operation during and after a major earthquake. The most expeditious way to achieve this is through the adoption of nation- ally applicable seismic standards for lifelines.

It follows that lifelines are the Achilles’ heel of modern society. They are the unprotected segment of our built environment without which life as we know it would cease to exist.

The damage to the lifelines in 1971, and again this last week, is the writing on the wall for the community and for state and federal decision-makers. Seismic standards for lifelines must be developed and adopted before the next magnitude 6 or larger earthquake pushes Los Angeles over the edge.