OPINION

September/October 2005

Costs and Benefits of Improved Seismic Monitoring

I was a member of the National Research Council panel charged with the task of analyzing the costs and benefits of im-proved seismic monitoring (NRC, 2005). The main focus of the report was the Advanced National Seismic System (ANSS), a U.S. Geological Survey program authorized by Congress in 2000 whose implementation has proceeded at an appropriated annual funding level (approximately $4 million) that is about one tenth of the planned level. At this rate, it would take about 50 years to complete the planned implementation of ANSS. The plan for ANSS consists of equal num-bers of strong-motion sensors (3,000 each) for installation on the ground (principally in urban regions throughout the United States) and in buildings and other structures, so the data obtained from ANSS are of equal importance for earth-quake science and earthquake engineering. In the following paragraphs, I summarize what I consider to be the most impor-tant insights contained in the report.

The combination of the earthquake hazard together with the vulnerability of the built and human environment creates earthquake risk. Earthquake risk in the United States is growing at an alarming rate, even in the face of remarkable ad-vances in earthquake science and engineering (EERI, 2003). This phenomenon is the direct result of unprecedented growth and prosperity, and the lack of focused, nationally applied, public policy that would cause the available design and reha-bilitation techniques to be properly and universally applied. Earthquakes continue to cause an unacceptable level of damage in terms of lives lost, property destroyed, and service interruption.

The potential benefits from improved seismic monitoring are many and varied. A fundamental role of the seismic in-formation derived from ANSS is to reduce uncertainty, leading to increased accuracy of building damage predictions and loss estimation, as the basis for more effective loss avoidance regulations, as well as enabling more effective emergency preparedness and response activities and improved earthquake forecasting capabilities.

The total estimated cost of ANSS includes $189 million for expansion and modernization of strong-motion capabili-ties, with annual operating and maintenance costs of $52 million per year. The relatively modest funding required for sig-nificantly improving seismic monitoring should be viewed in light of the potential for reducing the cost of constructing new facilities, strengthening existing structures to achieve proper performance, and losses that will be avoided after major damaging events. These costs of improved seismic monitoring should be considered from the perspective of the more than $800 billion invested annually in building construction, the $17.5 trillion value of existing buildings in the United States, and the expected loss of more than $100 billion from a single major earthquake in a heavily populated urban envi-ronment in the United States.

ANSS is expected to provide benefits in the form of avoided losses. Consequently, the costs of earthquake damage to the nation—without mitigation measures provided by ANSS—must form the benchmark against which the benefits are assessed. Losses or costs associated with earthquakes fall into five major categories—direct physical damage (to buildings and infrastructure), induced physical damage (including fires, floods, hazardous material release, etc.), human impacts (death and injuries), costs of response and recovery (including first-responder and building-inspection costs, etc.), and indi-rect economic losses (business disruption, social and environmental costs, etc.). The most recent estimate of annual earth-quake losses in the United States by the Federal Emergency Management Agency was $5.6 billion per year (after adjust-ment to 2003 dollars), with a single earthquake potentially causing losses greater than $100 billion.

Using a series of assumptions, the NRC panel made an approximate estimate of earthquake losses that could be avoided by using improved seismic monitoring information as the basis for implementing improved performance-based earthquake-engineering design. These assumptions relate to the value of the built environment within the U.S. and the rate of new construction, the cost of seismic rehabilitation and the number of existing buildings that need strengthening, and the annual expected loss from earthquakes compared with reduced losses when high seismic design standards are applied. These calculations indicate a total building-related loss avoided of about $140 million per year. Thus the losses avoided in a single year related to buildings alone almost equal the total capital costs of ANSS.

This estimate of benefits from enhanced seismic monitoring related to buildings does not include several important additional categories of benefits. One of these categories comes from improved loss-estimation model outputs, which result in increased public knowledge, confidence, and understanding of seismic risk; better correlation between seismic risk and building-code and land-use regulations; more efficient use of insurance to offset losses from disasters; and more accurate determination of the nature and growth of seismic risk in the nation. In addition, information about new and rehabilitated buildings and infrastructure, coupled with improved seismic-hazard maps, will allow policy makers to track incremental improvements in seismic safety through earthquake-mitigation programs.

Another category of benefits from enhanced seismic monitoring not included in the $140 million annual estimated sav-ings related to buildings comes from improvements in emergency response and recovery. These benefits include rapid and accurate identification of an event, its location and magnitude, the extent of strong ground shaking, and estimates of dam-age and population impacts. This information expedites hazard identification, promotes rapid mobilization at levels appro-priate to the emergency, and facilitates the rapid identification of buildings that are safe for continued occupation and those that must be evacuated. These are tangible benefits to the emergency management community, and ultimately to residents of seismically active regions of the country. Although difficult to quantify, the ultimate benefits are lives saved, property spared, and reduced human suffering.

The preceding paragraphs summarize what I consider to be the most important insights contained in the NRC report. On a more personal level, I was one of many earthquake scientists and engineers who, upon seeing the collapse of the twin towers in New York on September 11, 2001, which killed nearly 3,000 people and cost almost $100 billion, were imme-diately reminded of earthquake disasters—I witnessed similar horrifying scenes in Kobe, Japan on January 17, 1995, which involved even larger losses of life and property. The United States is prepared to spend hundreds of billions of dollars on preemptive wars for the stated purpose of reducing the threat of terrorist attacks. In my opinion, it is reasonable to expect the United States to also spend one thousandth of that amount (hundreds of millions of dollars) on ANSS to preemptively reduce the threat of earthquake losses by an amount that in just one year would probably exceed the total capital costs of ANSS.

References

EERI (Earthquake Engineering Research Institute) (2003). Securing Society against Catastrophic Earthquake Losses: A Research and Outreach Plan in Earthquake Engineering, Oakland, California, 62 pp.

NRC (National Research Council) (2005). Improved Seismic Monitoring—Improved Decision-making: Assessing the Value of Re-duced Uncertainty, Washington, DC: The National Academies Press, 171 pp.

Paul Somerville
URS


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Posted: 23 September 2005