If you shake a stubborn bottle of catsup hard enough, its contents will loosen up and pour. During an earthquake, the same thing can happen to otherwise solid ground. The process is called "liquefaction," and when it occurs during an earthquake, buildings can shift or sink, and underground storage tanks -- like those at the local gas station -- can float to the surface. Unfortunately, the pipelines attached to those tanks float at a different rate, causing line breaks that may lead to fires or flooding.
In many cases, collateral damage may be more destructive than the quake itself: fires, flooding, loss of vital services or destruction of key structures -- such as hospitals, highways or fire stations -- can dramatically increase the total losses associated with an earthquake.
The tremendous variety of possible damage and the influence of local circumstances have traditionally made it difficult for community leaders to predict expected damage levels and plan emergency responses to earthquakes. Perhaps more important, the lack of effective risk analysis has made it difficult to bring public attention to bear on legislative, zoning and building code changes that could help mitigate the effects of earthquakes. And, of course, all these local and state impediments to reliable estimates roll up to the federal level, making it all but impossible for federal authorities to realistically estimate the national earthquake risk.
In Search of a Standard
Congress began to address some of these issues in October 1977 with the passage of the Earthquake Hazards Reduction Act. Its purpose is to reduce "the risks to life and property from future earthquakes in the United States through the establishment and maintenance of an effective earthquake hazards reduction program." The act established the National Earthquake Hazards Reduction Program (NEHRP), which coordinates activities between various federal agencies, including the Federal Emergency Management Agency (FEMA). In the early 1990s, under the auspices of NEHRP, FEMA partnered with the National Institutes of Building Science (NIBS) to develop a standardized methodology for estimating earthquake damage.
"We started in about 1992 to develop an earthquake loss methodology," said Claire Drury, FEMA project officer for what is known as the HAZUS Loss Estimation Methodology Project. "We found that people weren't aware of potential losses and you can't promote seismic building codes unless people realize there is a benefit to doing this. So what we have done is build the model that will be used by regional and local governments to run loss estimates to help them recognize the potential hazards."
The project, directed by NIBS, established an eight-member Project Work Group (PWG) -- consisting of earthquake experts -- and an 18-member project oversight committee (POC), which represented user interests in the earthquake community. Additional assistance was elicited from over 80 corresponding members of the POC, whose views represented user and technical interests.
In 1993, PWG and POC defined the components of the loss estimation methodology, prepared an extensive set of objectives for developing the methodology, and generated a standardized list of earthquake-caused economic and social losses as methodology outputs.
Risk Management Solutions (RMS) of Menlo Park, Calif. -- a company that specializes in providing software and information services to the insurance and financial industry -- was selected to develop the methodology and was also hired to do the software implementation.
"The HAZUS methodology itself is a nationally applicable methodology," said Scott Lawson, an associate vice president at RMS with a Ph.D. in structural engineering who headed RMS's part of HAZUS. "The information that was gathered was on a national scale -- data like building inventory information, census data and the EPA-supplied toxic-site information. We have information on highways, bridges and dams.
"FEMA had collected a whole bunch of information during the civil defense era," Lawson continued, "and we took all that information and put it