Printer Friendly

America's faulty earthquake plans.

AMERICA'S FAULTY EARTHQUAKE PLANS

A major earthquake will happen here. But instead of preparing to cope with ground shaking, the U.S. government is withdrawing support from programs aimed at reducing the hazards of earthquakes. As a consequence, the nation's infrastructure is left at risk.

Earthquakes constitute a national threat. Each year over $500 billion is invested in constructed facilities, and much of the accumulated total is exposed to earthquake hazard, though the probability of destructive shaking varies markedly over the United States. Because both the U.S. population is increasingly concentrated in cities and Americans' lifestyles depend on vulnerable high-technology systems, the potential for devastation is growing steadily. A major earthquake in any metropolitan area will have economic aftershocks across the United States.

In 1977, Congress enacted the Earthquake Hazard Reduction Act, which established the National Earthquake Hazards Reduction Program to reduce the risks to life and property. The program is a multi-agency effort of the Federal Emergency Management Agency, the U.S. Geological Survey, the National Science Foundation, and the National Institute of Standards and Technology. Yet, according to a committee appointed by FEMA to review the NEHRP, every part of the program is underfunded and progress has not been commensurate with the potential risks.

Most activity to reduce the impact of a natural disaster is carried out as a sideline by organizations whose main purposes have little to do with the hazards of earthquakes. The responsibilities for earthquake hazards are distributed among such a variety of organizations that even managing information is problematic.

A 1980 report by the National Security Council, which concluded that major earthquakes in both the western and eastern United States were inevitable, said that local officials were not prepared for a cataclysm that could kill thousands of people and cause billions of dollars in property damage. It concluded that coordinated plans for dealing with major earthquakes could save thousands of lives and prevent large-scale economic damage. "Yet to date," points out Senator Alan Cranston of California, "there has been no serious federal effort to plan to cope with such a catastrophe in the eastern United States. And in the western United States, the effort lags in translating research findings into application."

In addition, the level of U.S. earthquake engineering expertise has been decreasing. Americans are faced with a situation in which they don't know where or when an earthquake will happen. When one does occur, they are neither protected nor prepared for its aftermath.

Extensive Risk

California has gained notoriety for its frequent earthquakes. A postulated earthquake of Richter magnitude 8.1 in California has the potential to kill or injure tens of thousands of people and cause more than $60 billion in damages. In 1988, the USGS established a 60 percent probability that an earthquake of 7.5 or greater magnitude will occur on the San Andreas Fault in southern California in the next 30 years and a 50 percent probability that a magnitude 7.0 or greater earthquake will occur on the San Andreas or the Haywood Fault, in the San Francisco Bay region, in the same period. The largest earthquake intensity expected there in the next 250 years is only slightly larger than that expected in the next 50 years. But in the most earthquake conscious of all the states, not all of California's 500 local jurisdictions have related programs.

Earthquakes are not just California's problem. The American Association of Engineering Societies has reported a nearly 100 percent probability of a significant earthquake in the East in the next 23 years. An earthquake of the same Richter magnitude will affect a much greater area in the East than in the West, where the fault-ridden crust thins out the shock waves. Because of uncertainty about the source of an 1886 earthquake in Charleston, S.C., the USGS concluded in 1982 that a similar event could not be ruled out for the rest of the eastern United States. The tectonic province in the East is so large that ground shaking comparable to that in Charleston can be postulated for almost any site on the eastern seaboard.

When the central states have a major earthquake, the result is generally felt throughout an area of over two million square miles. In this area, a series of catastrophic earthquakes on the New Madrid Fault occurred during the winter of 1811-12. Eighteen were felt as far away as Washington, D.C., and southeastern Missouri was so profoundly ravaged that Congress passed the first Disaster Relief Act in 1815. Now pipelines for the north central and northeastern United States pass through the Mississippi Embayment, close to the New Madrid Fault. There are four to five pipeline breaks a week in Illinois alone; an earthquake would wreak havoc on these old lines.

Last December's earthquake in Armenia was reported to have been its greatest in 300 years. It is sobering to note that east of the Rockies the United States has had five earthquakes of similar magnitude in the past 300 years. None has occurred in this century but we are sorely vulnerable. The Armenian quake was devastating because of the large number of people in buildings that were not designed to withstand earthquakes. In the eastern United States, seismic design and construction rarely are required and many buildings in the United States are as inadequate as those in Armenia. American lifelines have more at risk than those in Armenia; for instance, there were no Armenian highway interchanges.

Fundamental Studies

Tectonics is concerned with the structure and deformation of the earth's crust. Plate tectonic theory pictures approximately the top 100 miles of the earth's surface as divided into more than a dozen main plates, each hundreds or thousands of miles in size and all drifting independently. Most earthquakes occur along plate boundaries where there is relative motion. Those with the highest energy take place along the "ring of fire," which marks the boundary of the Pacific plate that borders Alaska and the West Coast states. The Pacific plate pushes under the overlying plate and occasionally locks with it along a fault, accumulating shear and compressional strain. An earthquake's release of this strain signals that movement of the subducting plate has begun again. Because the rupture plane does not reach the surface, most faults are hard to identify.

More detailed studies are needed of how stress is accumulated, distributed, and released along plate boundaries. One project that would have gathered information on core pressure, temperature, and the state of stress at depth was the Deep Drilling Project, near Cajon Pass, Calif. Funding for it was halted last year, after drilling had reached a depth of 14 kilometers.

Intraplate earthquakes, which occur within plates, account for earthquakes east of the Rockies. Areas believed susceptible to a major earthquake include the Meers Fault in Oklahoma; the New Madrid Fault in Missouri; Charleston, S.C.; and the St. Lawrence River region in Canada.

Because of uncertainties about the origins of earthquakes, related hazards are unpredictable. Ground shaking, the most pervasive and important hazard, can now be estimated only within broad limits, despite the fact that it is an important component of vulnerability studies, specification of earthquake design parameters, risk assessment, and code specifications. Source models are fundamental to understanding the nature of ground shaking. There is also uncertainty in establishing seismic source zones and structures and their potential, and uncertainty about the propagation of seismic energy. Hazard Delineation and Assessment. These gaps spill over into the intensity and attenuation of motions in the East, horizontal and vertical variations in motion over short distances, the effects of topography, and the responses of buildings and other structures. A lack of tools is a major shortcoming of the NEHRP. Nevertheless, reductions are threatened in regional and local earthquake data collection programs and much of the nation's monitoring equipment is obsolete or has limited capabilities.

Because of the concentration of nuclear power plants in the East, the Nuclear Regulatory Commission has had the lead role in monitoring in the area. However, with a sharp drop in new plant start-ups, the NRC is phasing out its funding of earthquake monitoring. As a transition measure, which will end in 1993, the NRC is supporting the establishment of the eastern section of a proposed new national network that can record strong ground shaking. No funds are now available for installing the western section or for operating it if it were installed.

The network would not replace all of the functions of existing regional networks. Probably it would record only 10 percent of earthquake events, an inadequate number for learning about seismicity. Because of the relatively wide spacing of stations, data would not be produced on small events in the East, which provide the basis for hazard-related studies. Some networks funded directly by the NEHRP through the USGS also are threatened by a loss of funding that would upgrade them to acceptable standards or even keep them operating with existing instruments. Currently, several thousand instruments for recording strong motions have been installed by various organizations for various purposes, but there is no national program to coordinate the location of instruments and the use of the data. A Testing Facility. The value of earthquake-resistant design is illustrated by a comparison between the 1976 Tangshan, China, earthquake and the 1985 Valparaiso, Chile, earthquake of the same magnitude (7.8). In China, 250,000 people died, 800,000 were injured, and the regional economy was devastated. Because Chile requires earthquake-resistant construction, few died and damage there was moderate for such an earthquake.

An earthquake will ferret out the weak points of structures or equipment. Mitigating the hazard requires evaluating all facilities that make up the built environment--buildings, bridges, dams, freeways, utility systems, and pipelines, as well as nuclear reactors and associated power generating equipment and chemical and petroleum processing plants. Current assessment is generally restricted to major dams and nuclear power plants and questions raised by these assessments often can't be handled with confidence.

A need exists in the United States for a large-scale testing facility that can help to provide these answers. Some of the information can come from studying the behavior of real structures and equipment in real earthquakes. But when questions arise about novel systems, there are no sound predictions about their performance. In a large testing facility, engineers could create and test specimens for the accumulation of damage, redistribution of forces, and their toughness and energy-absorbing capacity.

A large test facility would also aid in research on retrofits of existing structures. Many recently upgraded buildings have yet to be tested by even a moderate earthquake. In California, where they are based on experience, retrofits require building new lateral-load-resistant systems within the older gravity-load-resistant buildings. For schools and hospitals, these techniques can cost up to 80 percent of the cost of a new building, so the technique is not economically feasible for structures in regions of moderate seismicity.

The United States has only two shaking tables of about 37 square meters with a capacity of 60 tons. Russia and Japan have shake tables, 900 and 225 square meters in size respectively, with capacities that exceed 1000 tons. Several strong testing walls permitting pseudodynamic testing have been built here. But even these are underused because of inadequate funding. The United States does have cooperative programs with Japan to use their facilities. But they shouldn't be viewed as a permanent substitute because few Japanese firms are willing to lease to outsiders for more than three months.

A 1984 National Academy of Science/National Research Council report recommended accelerated planning for a national earthquake engineering experimental test facility. The first part of a four-part study was completed in 1987 but further consideration of the facility is now dormant. Such a facility would be costly. According to Richard Wright, director of the NIST Center for Building Technology, "Its cost of creation and the annual operating cost each can be on the order of $100 million; that is something extraordinary for civil engineering research. The civil engineering research program funded by NSF, for instance, including earthquake engineering and other areas, is less than $30 million annually.... That is one side of the question. The other side is that the Japanese, for instance, have several large-scale earthquake facilities and are gaining leadership in earthquake engineering."

Of course, earthquakes also cause nonstructural damage to buildings, but there is little guidance available for architectural detailing. A classic example of its importance is the modern fire station that withstood the 1971 San Fernando earthquake. Its doors jammed, trapping fire engines inside.

Other research gaps are in soil/structure interaction and the effects of embedment, which may drop input level, especially at the higher frequencies important for mechanical systems. If this is true, structures can be designed for reduced seismic input. Prediction Research. Foreknowledge of an earthquake can reduce its consequences. Even a little advance warning can be beneficial. In February 1975, a Richter magnitude 7.3 earthquake in China's northern provinces was predicted. The quake demolished 90 percent of the city of Haiching's masonry buildings, but relatively few people were killed because they were outside. A year later, the Tangshan (magnitude 7.8) earthquake was not predicted and 250,000 people died.

Despite a handful of successes, earthquake prediction is unreliable. Understanding the physical processes that lead to an earthquake requires understanding the conditions that exist in the earth's crust and upper mantle. Which physical properties are most critical or the nature of the instability that causes an earthquake is not known.

Instead of investigating fundamental earthquake phenomena, prediction research initially focused on discovering precursors. The geophysical precursors reported before an earthquake include changes in the seismic compressional wave velocity, in the local gravity field, in electrical resistivity of the crust, and in the water level in wells. Premonitory geochemical changes include chemical composition ratios of stable isotopes and the concentration of helium and other gases, such as radon, in the groundwater. Gathering observations of these phenomena is very costly because moderate earthquakes occur infrequently in any given area and the potential source areas are vast, so now research is swinging away from precursors and is studying fundamental seismic processes.

In 1985, the USGS ventured its first prediction--of an earthquake for 1988 (plus or minus four years) at Parkfield, a small town in central California along the San Andreas Fault. Over the past 150 years, moderate earthquakes have occurred about every 22 years at Parkfield, so it provides an opportunity to gather data on a dozen physical phenomena that are precursors of an earthquake. Some seismologists recommended that experiments similar to the one in Parkfield should be replicated in at least four other key areas. However, funding doesn't allow other efforts. Induced Seismicity. Studies of induced seismicity are important to earthquake prediction and could ultimately provide a method for mitigating their intensity at the source, resulting in a number of small earthquakes instead of a single large one. When earthquakes were inadvertently triggered by deep-well waste disposal at the U.S. Army Rocky Mountain Arsenal near Denver, an ensuing experiment used fluid injection in an oil field near Rangley, Colo. It showed that under certain conditions the occurrence of an earthquake can be triggered.

The injected liquid functions in two ways to cause an earthquake. The fluid pressure between the two faces of a fault reduces the contact pressure and the liquid acts as a lubricant. When forces in the earth's crust produce relative shear strain across the fault, the liquid apparently promotes sliding and the abrupt reduction in rock stress generates an earthquake.

This pumping technique might be used to relieve stresses on a large fault by increments. George Housner, a professor of engineering at California Institute of Technology and chairman of the National Research Council Committee on Earthquake Engineering, describes how it might be done and why it hasn't been tried yet. "Three wells could be drilled in which the center one serves as a pumping well to inject liquid and on each side is a dry well to promote sticking on the fault. In this way one might produce a sequence of small earthquakes along the fault, thus avoiding the occurrence of a great earthquake. However, no one has tried this on a large fault because if a large earthquake were to occur, the liability would be staggering."

At large reservoirs behind high dams, abrupt changes in water level and pore pressure have caused earthquakes. There are over 20 cases worldwide of inducing earthquakes by the initial filling of large reservoirs. These reservoirs provide another opportunity for controlled earthquake experiments.

Hazard Awareness and Preparedness Planning

The last nationwide program for citizen preparedness existed more than 25 years ago, during the period of nuclear confrontation. Most state and local jurisdictions outside of California have ignored planning a response to an earthquake prediction and organizing for postearthquake recovery and reconstruction. Through FEMA, federal support for local emergency planning and preparedness activities is limited. State and local agencies are prevented by regulations and guidelines from using existing funds in the most productive ways. For example, support to state and local jurisdictions requires that every federally supported program be responsible for attack/war-related duties. This discourages state and local governments from focusing on the earthquake threat.

An inventory of buildings is one of the key steps in hazard reduction. Hazardous buildings and other structures need to be identified and either strengthened or demolished. Yet no national or regional inventory exists outside of California. The cost would be so great that now the major effort is an attempt to find low-cost substitutes for a thorough inventory.

Other hazard-reduction approaches, such as seismic design in building codes and land-use management, have fallen flat in most regions outside of California. The NEHRP markets to reluctant or disinterested users of building codes. Vested interests bog down adoption of the codes. The late Erie Jones, former executive director of the Central U.S. Earthquake Consortium, pointed out that, locally, potholes are more important than codes and that local structural engineers feel that wind loading is sufficient; they are not accustomed to seismic design.

At Congressional hearings in March on whether devastation similar to that in Armenia could happen here, it was pointed out that the United States also lacks rescue and medical teams trained to deal with the consequences of a devastating earthquake.

Insurance

The insurance industry, which could find itself out of business after a major earthquake, has begun to study the consequences of such an event. However, the lack of hazard mitigation information and procedures has impeded development of new insurance plans.

Currently, the property and casualty insurance industry in the United States is worth about $100 billion. Ten percent is a standard estimate of the loss it can sustain in a single event. The industry's Earthquake Project estimates that a midday earthquake of Richter magnitude 7.5 on the Newport-Inglewood Fault in Los Angeles (a relatively well-prepared area) would cause 17,000 deaths and $50 billion in insured property loss. Additional losses would arise from uninsured damages and the interruption of normal activities. One government official estimates that these secondary losses would be 5 to 15 times greater than primary losses.

Few property owners carry earthquake insurance and those who do have a deductible of 10 percent of the coverage. Furthermore, present earthquake-insurance proposals don't address either land-use or seismic-resistant design in building codes. Without incentives, there is no motivation to stop the construction of high-risk structures.

The consequences of a failed insurance industry would have broader repercussions. In a hearing before the U.S. House of Representatives Subcommittee on Science, Research and Technology, John Drennan, assistant vice president and actuary at Allstate Insurance Co. in Northbrook, Ill., noted, "Many in the private insurance and reinsurance industry are convinced that a major earthquake would result in such serious financial losses to the insurance industry and to the financial community as a whole that they would be unable to continue with normal operations. A serious earthquake in the Midwest or California could result in losses of over $50 billion." With their capital depleted, insurers would be forced to dump stocks and bonds onto the market all at once.

Funding

Federal funding has not been commensurate with the potential for loss. Over the past decade, about $600 million has been spent on the NEHRP; that is about half of what Tokyo spends in one year on hazard mitigation. Since the 1977 creation of the NEHRP, inflation has eroded its budget. In real purchasing power, current funding of about $67 million is less than two-thirds of the 1977 appropriation. A $198 million annual budget is recommended by the NEHRP Expert Review Committee for 1989-93. That figure represents 0.3 percent of a $60 billion earthquake.

The gap between needs and funding is widening. Funding for the NEHRP is so eroded that experts in separate areas of the NEHRP may be forced to work in other fields (such as defense research on missile silos and blast detection) to survive. In addition, the facts about opportunities in the field have reached graduate schools, where there has been a large decline in earthquake engineering students during the past five years.

Moreover, there are disagreements about how best to spend the available monies. Of prediction and engineering, the two parts of the Earthquake Hazard Reduction Act, prediction gets about $30 million, engineering about $15 million. There are also questions about how much of NSF's earth science funding from the NEHRP is applied to studies that clearly contribute to the NEHRP.

According to Tom Tobin, executive director of the California Seismic Safety Commission, "Our research efforts in California are crumbling just at the time the state law requires identification of hazardous buildings; at a time when governments and businesses are willing to bite the bullet and strengthen unsafe buildings; at a time when 10 years of research and investment in test facilities have set the stage to attack our biggest problem: existing hazardous buildings. We may well need new programs and facilities, but you cannot abandon the researchers and research facilities that have already been established and are intended to produce results that we need."

Leadership

Besides underfunding, the federal program has been criticized for a lack of leadership, coordination, and accountability. Because the program is fragmented and earthquake programs are a small fraction of each agency's budget, there is no high-level management support. Says Tobin, "earthquake hazard reduction is far too important to have a leaderless program lost among competing demands and priorities in the crush of everyday business in Washington, D.C."

The FEMA is the lead agency for the national earthquake program. But earthquake-related activities are not a high priority for the FEMA, which has no authority over other agencies in the earthquake program. The earthquake community is not convinced that any NEHRP agency can provide the necessary leadership. The FEMA-appointed NEHRP Expert Review Committee recommends forming a Federal Earthquake Oversight Commission to assume the role now assigned to the FEMA. Recently, Cranston and other U.S. senators introduced legislation to make the USGS the lead agency in the NEHRP. They reason that another agency is not needed and that the USGS's field network can emphasize application.

A Consistent Message

The message from expert panels and review committees is clear, often repeated, but ignored: the United States is not prepared for a major earthquake. The nation is complacent because there has been no severely destructive earthquake recently. Most of our measures that cope with natural hazards are reactive.

Although the federal government has much to lose in a catastrophic earthquake, its commitment to strong state and local programs is minimal. At risk is the infrastructure of key military bases, defense contractor facilities, and economic activities that contribute to the defense, maintenance, and welfare of our nation.

There is no doubt that significant achievements have been made in earthquake engineering and research. But in many cases this knowledge has not been adequately applied. And, most importantly, past accomplishments and current efforts fall short of making our nation reasonably secure against earthquakes. With greater understanding and preparation, Americans will be less susceptible to the whims of nature.
COPYRIGHT 1989 American Society of Mechanical Engineers
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Rosen, Jerome
Publication:Mechanical Engineering-CIME
Date:Oct 1, 1989
Words:4029
Previous Article:R&D in the fast lane.
Next Article:Seismic stops for nuclear power plants.
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |