EARTHQUAKES: LESSONS FROM THE PAST, PART 2

Part 1 appeared in the June 2000 issue.

It takes constant effort to ensure that fire and rescue professionals are familiar with the dynamics of postearthquake structural collapse operations as well as the use of survivability profiles to determine where live, viable victims are likely to be found and to determine when it is appropriate to end search and rescue operations. It requires a major commitment for fire departments and other response agencies to ensure their members are prepared to stabilize damaged buildings, tunnel into hidden void spaces, lift heavy debris, coordinate the actions of convergent responders, and extract the injured. It also takes a certain mindset to admit that local resources may become overwhelmed by a major earthquake and to PLAN for the timely request and effective use of mutual aid from other jurisdictions (and even from other states and nations), which begs the following questions:

  • What will be the fate of the hundreds or thousands of victims who may be trapped alive when the next major quake strikes Southern California, San Francisco, Seattle, Anchorage, or the New Madrid fault region?
  • Will all available urban search and rescue resources, including those from other states and nations, if necessary, be committed to help locate and rescue them in a timely manner?
  • Will round-the-clock search and rescue operations be supported for as long as it takes to locate and remove all live victims?

Fortunately, in some other seismically active regions of the United States, lessons from earthquakes in Mexico City, Armenia, the Philippines, Italy, Turkey, Cairo, Athens, Taiwan, and Oakland/ San Francisco have been heeded, and local fire and rescue agencies have learned to plan for round-the-clock urban search and rescue operations to ensure that every trapped person is given the best possible chance of survival.

CONSTRUCTION AND DESIGN OF STRUCTURES

Because of their increased potential for collapse during earthquakes and fireground operations, firefighters have been forced to treat certain types of buildings as dangerous enemies all the time. George Housner, Cal Tech engineering professor emeritus, recalls that, ironically, some building ordinances championed by the fire departments in Southern California contributed to massive destruction and complicated search and rescue problems in the 1933 Long Beach earthquake (“A Jolting Wake-Up Call on Preparing for Quakes,” The Times, October 15, 1999).

Some fire departments in the early 20th century pushed for building codes requiring that parapets projecting five to eight feet above the front of buildings be added. The parapets allowed firefighters to climb to the roof of structures across the street from the burning building and direct hoselines from behind their protective cover.

Although the parapet at one time may have helped the cause of knocking down fires in storefronts and other businesses, it creates problems for modern fire and rescue professionals. It creates excessive stresses on old unreinforced buildings when the ground shakes and, along with facades, sometimes falls “spontaneously” because of poor construction or design practices, burying shoppers and other pedestrians beneath tons of wood, metal, and other material. Facades also fall on people exiting buildings during earthquakes-one reason experts for years have advised people to avoid running outdoors when the earth shakes. Quake-induced parapet and facade collapse can complicate search and rescue operations and delay assistance to people buried deep within damaged buildings (they also present hazards while firefighting).

According to Housner, fire departments also influenced the development of early building codes that made it common practice to create loosely fastened systems connecting roofs and upper floors to exterior walls. The theory held that loose connections would allow the roofs and upper floors of burning buildings to simply fall into the middle without pulling down the exterior walls. By the time a building was so consumed with fire that roof collapse was imminent, firefighters would often have moved outside the structure to work in “defensive mode” to prevent fire spread.

Even during defensive fire operations, the collapse of the exterior walls could bury firefighters beneath tons of bricks, so it was considered preferable by some to let the roof and upper floors fall into the middle without pulling down the walls. But in an earthquake, poor connections in old buildings can cause people to be trapped by the failure of multiple floors and roofs, although retrofitting might help prevent total collapse.

Similarities to International Disaster Conditions

Many of the collapsed buildings in Turkey, Taiwan, and Kobe were similar in design and construction to buildings found in the United States. This is starkly evident in the Greater Los Angeles area. Although there are marked differences between the structures in those countries and those in the United States, the differences are not so great that Southern Californians should persist in observing such distant events with invulnerable detachment, lulled by assurances that U.S. methods of erecting buildings and freeway overpasses are naturally superior to those that failed in other countries.

Despite remarkable advances in earthquake-resistant engineering and retrofitting, buildings of different styles and ages continue to fail during large quakes in California. Tens of thousands of buildings in Southern California were built before the most recent seismic codes were enacted. These buildings are out there now, occupied by people, and local fire and rescue agencies must be prepared to manage the consequences if they fail in the next big quake.

Worldwide, millions of existing buildings and other large structures (i.e., freeway overpasses, tunnels, and so on) in modern cities were built before the advent of modern seismic codes and are not subject to retrofitting campaigns, even though active earthquake faults have been found nearby. This is true of many regions of the United States, including the New Madrid Fault Zone, New York City, and other places not traditionally considered quake-prone. Many nonquake-hardened structures in these regions are vulnerable to catastrophic collapse even during moderate or minor quakes. These collapsing structures threaten not only the inhabitants but also firefighters and other rescuers called to locate, treat, and extract trapped victims.

Evidence from recent earthquakes indicates that new and retrofitted structures are safer than older, nonreinforced structures, but even quake-resistant and retrofitted structures have failed in severe earthquakes. In 1997, Taiwan adopted California-style earthquake engineering and building codes. However, because of inconsistent construction standards and inspections, and perhaps because the codes were simply not sufficiently strong to deal with the shaking that occurred, thousands of buildings failed in the Taiwan earthquake. Are there similar quality assurance problems related to construction practices in California and other states? The consensus seems to be a resounding Yes.

Based on the experiences of recent earthquakes, Americans shouldn’t assume that postquake conflagrations like those that swept Kobe and Tokyo are strictly an Asian phenomenon rooted in narrow streets and wooden homes built too close together. They shouldn’t assume that retrofitting of pre-1933 buildings is an iron-clad guarantee against failure when a great quake strikes or that parking structures at the local malls won’t pancake down layer upon flattened layer just as they did in the Northridge and Whittier earthquakes.

Nor can we assume that large apartment buildings will remain standing in the face of extreme shaking; that large malls will hold up; or the “soft” first floors of many multilevel condos won’t collapse into subterranean parking areas or into the street. In fact, we can’t even assume that every fire station will withstand the effects of a severe quake unscathed or that there will be sufficient numbers of local fire engines and rescue teams to immediately snuff all the earthquake-related fires and locate and remove all victims trapped in the rubble. In truth, it should be generally accepted that assistance from outside jurisdictions will be needed if a major damaging seismic event were to occur in any densely populated region of the United States.

Here are more lessons learned in recent earthquake disasters:

  • Residents should think twice before assuming that by standing in a doorway they will be protected if their apartments are crushed by upper floors. The doorway will offer little protection if the entire building collapses. Firefighters conducting search and rescue operations at the Northridge Meadows apartments and other collapse sites found that survivable void spaces were more likely to be between beds and dressers, desks, and other sturdy pieces of furniture. Remaining in bed or attempting to run to the doorway apparently doomed some victims, who were crushed when buildings were flattened.

The truth is that no engineer or building contractor can guarantee a particular apartment complex, school, freeway overpass, shopping mall, parking structure, office building, or high-rise will survive the next big earthquake in Southern California.

Thousands of miles of underground pipelines carrying hazardous, flammable, and explosive materials lie beneath many of our cities; any of them could rupture during the next quake.

Water mains may also rupture, as they did in Northridge, creating big problems for firefighters. Few people can conceive of the possible effects of hundreds of fires erupting simultaneously in many cities across a large band of earthquake-impacted land and spreading to damaged buildings in which victims are trapped, overwhelming firefighters who must decide between taking the time to rescue victims or trying to knock down the fire before it gets to them. Even fewer can conceive of such an event occurring on a hot, dry day with Santa Ana winds whipping across the basin and valleys at 40 to 60 miles per hour, spreading fire on a scale previously seen only in wildland situations.

Add to that the potential for dam failure which, according to studies by the U.S. Geological Survey (supported by evidence from the 1928 failure of the William Mulholland-designed St. Francis Dam), could kill tens of thousands of people in Los Angeles County alone following a violent local quake. Doubters need only look back to the 1971 Sylmar quake, which left the Van Norman Dam on the verge of collapse in the San Fernando Valley.

More Disturbing Lessons

When planning for future disasters, “simultaneous” disasters must be considered. Floods or wildland fire storms, for example, may come on the heels of a large earthquake. Such a situation would multiply the demands on fire/rescue/medical agencies in ways that might be difficult to imagine.

Were a series of tsunamis to strike the densely populated Southern California coastline just minutes after the next big quake, extensive areas could be wiped out. Scientists at the University of Southern California’s School of Engineering are currently preparing computer models of the potential tsunami impact areas, and a countywide task force is developing a public education program and emergency response plans for such an event. Recently, scientists announced the discovery of two major faults directly beneath Lake Tahoe and the resulting potential for 30-foot-high tsunamis to be generated by this 1500-foot-deep lake (the third deepest lake in the world). This would cause life loss previously unimagined!

BUILDING ON PAST LESSONS

Being better prepared for succeeding disasters is not entirely a doom and gloom story; it is a story of evolution. Many lessons learned from the 1994 Northridge quake, for example, can be traced to the 1971 Sylmar quake that devastated parts of the San Fernando Valley and killed dozens of people. Since then, various agencies across California-in association with the State Seismic Safety Commission, the Governor’s Office of Emergency Services, the State Fire Marshal, and FEMA-have been engaged in a campaign to upgrade earthquake-resistant construction codes, educate the public, and improve statewide capabilities to manage the emergency consequences of seismic events by providing specialized training, equipment, and other resources to fire and rescue agencies. Without question, this sustained effort has already resulted in many saved lives and will pay huge dividends in terms of future postquake survivor stories.

There is ever-increasing hope for people who become trapped in collapsed structures, in part because of better seismic codes and building design, and also because of revolutionary improvements in the emergency response capabilities. In recent years, the efforts of fire/rescue professionals around the world have been buoyed by the frequency with which people have managed to survive post-collapse entrapment for long periods under conditions that would normally cause a high incidence of mortality.

In the Taiwan quake, several days after the main shock toppled thousands of buildings, a South Korean rescue team using a search camera (a remote-probe video device equipped with a two-way microphone that can be inserted into void spaces by way of an extendable pole) detected the voice of a child deep within a collapsed apartment complex, the entire bulk of which had collapsed into the basement, creating a multistory pile of concrete slabs and walls.

The search camera allowed rescuers to spot several people lying in a narrow void space between collapsed floors of the building. All were deceased except one young boy, who had spent the previous 80 hours lying among the dead in complete darkness. After nearly 12 hours, the boy was extracted; he had only minor injuries. It was yet another survival story that might have been repeated many times if there had been sufficient amounts of technical search equipment and numbers of highly trained USAR teams to use it.

In the wake of major seismic events that occurred in California and other areas of the world, firefighters and search and rescue personnel in quake-prone areas of the United States have learned valuable lessons about how to assess damage and work within structures that had their integrity severely compromised by violent ground shaking. Another positive development has been the growing international phenomenon of well-organized, highly trained, well-equipped urban search and rescue task forces that can be mobilized practically anywhere within relatively brief time periods.

In the United States, Australia, New Zealand, Japan, and other nations, the advent of specially trained USAR teams has vastly improved the survival odds for trapped victims. So has the new emphasis on training local firefighters to manage earthquake rescue operations. These developments have elevated post-earthquake search and rescue operations to the highest level of preparedness ever.

For valuable lessons learned from earthquake-generated failures to be used to prevent similar disasters, seismologists, engineers, and emergency responders must communicate and work together to translate acquired knowledge into increased survivability for citizens who live and work in these structures and to improve the safety and effectiveness of future USAR operations. This knowledge should be woven into the fabric of seismology, earthquake engineering, and consequence management-i.e., fire and rescue services.

SURVIVAL PROFILING AND SURVIVAL LINKS

An example of the need for better communication and interaction between earth scientists, engineers, and fire/rescue personnel can be seen with respect to a relatively new (and seldom-discussed) idea that might be called survival profiling. In recent years, experienced search and rescue professionals have begun to recognize commonalities that appear to link the survival of some trapped victims with certain aspects of building design, characteristic collapse patterns, and other factors. In some cases, the survival link seems to be related to the design standard under which the building was constructed or the manner in which the building was retrofitted for earthquake hazards. Taking advantage of these characteristic survival links and developing more effective search and rescue methods can improve the survival profile of existing and future structures.

Another survival link is related to the vast improvement of USAR capabilities that has occurred during the past decade. The availability of new technology and training for fire/rescue personnel, the advent of USAR canine search teams, and the development of USAR Task Forces have greatly increased the efficiency of search operations in collapsed structures.

It is becoming increasingly common for USAR teams to discover live victims (sometimes many days after the event) who have survived structural collapses because their beds or desks resisted the complete flattening of their bedrooms or offices. This indicates a major role played by certain structural components and furniture in the formation of survivable void spaces when buildings fail during earthquakes. Live victims are typically found in the void spaces that naturally occur in V-type, pancake, and cantilever-type collapse patterns. This can be contrasted with collapse patterns (such as those witnessed following the Armenian earthquake, the Cairo quake, and many others) in which building components disintegrate and fall into tightly compacted piles with few survivable void spaces. In these situations, the rate of mortality is far higher, for obvious reasons.

The existence of characteristic survivable void spaces in certain construction styles-combined with recent innovations in rescue operations and recognition and rapid treatment of trauma-related maladies such as Crush Syndrome and Compartment Syndrome while victims are still being extracted-has greatly improved the chances that trapped victims will be rescued alive and survive over the long term. Such was the case in the Northridge and Mexico City quakes, where victims survived after being trapped for periods ranging from one to 13 days.

Other examples in which design appears to provide a significant survival link-even during failure-include the collapse of reinforced concrete parking structures, freeway overpasses, and double-deck freeways and bridges. When these structures fail, experienced firefighters know to search for live victims in survivable spaces: next to (or inside of) automobiles and between beams within the collapse zone. Recent examples include several collapsed parking structures and overpasses in the Northridge quake and the Nimitz Freeway failure resulting from the 1989 Loma Prieta quake.

Conversely, rescuers at some earthquake-related collapses have discovered deceased occupants in locations that indicated they were attempting to reach door frames and other locations they had been led to believe are safe havens during earthquakes. Tragically, some motorists actually parked their autos beneath beams and other supporting features of double-deck freeways and overpasses during earthquakes, expecting to be shielded from falling debris, only to be crushed when those beams flattened their automobiles at the moment of structural failure. These victims might have been saved if they had known about predictable collapse patterns-the survival line-that might have left survivable void spaces a mere few feet away from where they had stopped their cars.

In recent years, experienced rescue teams have recognized and incorporated these anecdotal lessons and have developed survivability profiles intended to guide rescuers to the areas of collapsed buildings in which live victims are most likely to be found. The question then arises: Might not these same survivability profiles be used-or expanded on through formal research-to design buildings with higher levels of survivability by taking advantage of existing structural characteristics and expected furnishings to increase the incidence of survivable void spaces in buildings that fail during earthquakes? This question should be posed to architects and earthquake engineers in quake-prone regions.

The development of fire department-based specialized rescue units is another effect resulting from the experiences of past earthquakes. After the 1987 Whittier earthquake, local fire departments developed an extensive array of specialized rescue units and teams to manage the effects of collapsed buildings. Now commonly known as urban search and rescue, this discipline has expanded to include swiftwater rescue, mountain rescue, and practically every other type of technical rescue.

Following dual national disasters in 1989 (the Loma Prieta earthquake and Hurricane Hugo), where urban search and rescue was identified as a weak link in local, state, and national response systems, the Federal Emergency Management Agency (FEMA) was directed to develop a national USAR system to provide more timely and effective search and rescue assistance to state and local agencies at collapsed buildings and other major entrapment situations. FEMA created a network of 27 strategically located, 62-person USAR Task Forces; each is capable of deploying anywhere in the nation within hours of a disaster.

When the Northridge quake struck in 1994, some saw these efforts as prophetic. The newly established USAR systems proved highly effective in mobilizing teams of highly trained and equipped rescuers to locate and extract victims from collapsed buildings. Other earthquake preparedness measures, such as fire department earthquake plans, also proved effective. They gave firefighters the tools with which they could rapidly mitigate potential conflagrations, treat thousands of injured people, and provide a wide array of other public safety services in a timely and effective manner.

Yet, even with these advanced USAR capabilities in place, the Northridge quake presented surprises that have sobered experts who know that additional (and more powerful) earthquakes are almost certain to challenge-if not overwhelm-some of these systems in the future. The Northridge and Kobe quakes demonstrated an acute need to develop closer working relationships (and to improve information sharing) among seismologists, fire/rescue professionals, and emergency planners. This is especially evident when one considers the rate at which new seismic hazards are being discovered.

The Northridge quake occurred on a buried thrust fault that was not even known until it ruptured nine miles beneath the surface of the San Fernando Valley. In the wake of Northridge, seismologists have discovered (or postulated) the presence of many more buried thrust faults-some of which appear to be capable of delivering even more devastating blows to densely populated areas-beneath the surface of Greater Los Angeles. In fact, it is now recognized that hidden thrust faults are a major cause of the tortured topography found in parts of Southern California, and they may represent nearly as great a danger to the large cities as other well-known features like the San Andreas Fault.

Sources of important seismological information may include local universities and geological or seismic research centers, state geological and seismic agencies, and the National Geological Survey. One model of this level of interdisciplinary collaboration is found in Southern California, where urban search and rescue specialists from the County of Los Angeles Fire Department have developed close contacts with seismologists from the California Institute of Technology and the University of Southern California (via the Southern California Earthquake Center), to ensure that earthquake planning and training are consistent with the true seismic hazards.

Among members of the local fire/rescue services, this is leading to a better understanding of the forces that drive the seismic disasters that periodically strike Southern California. It is a relatively new partnership that will enhance the planning process for earthquakes that are certain to strike the region. The old adage “Know your enemy” (in this case, the enemy being the consequences of ground fault rupture) applies here.

This collaboration has also helped seismologists to better understand the needs of emergency responders (e.g., probabilities of future seismic events and their possible magnitude, advanced warning systems, and rapid identification of the location and magnitude of ground fault rupture to rapidly deploy resources). As a result, we are finding that there are ways in which seismologists and other earth scientists can enhance the ability of fire/rescue agencies to react to earthquakes. Expanded interaction between fire departments and seismologists in other parts of the nation may yield similar benefits.

These and other lessons will continue to be integrated into the emergency planning and response systems of United States fire and rescue services. The next major damaging earthquake will test the efficacy of all these efforts and will, once again, provide a storehouse of new experiences and knowledge with which to build future improvements.

LARRY COLLINS is a fire captain, rescue specialist, paramedic, and 20-year veteran of the County of Los Angeles Fire Department (LACFD). He is currently assigned to Urban Search and Rescue Task Force 103, responsible for planning, instructing, supervising, and conducting technical rescue operations across the LACFD’s 2,278-mile jurisdiction. He is assigned as a search team manager of CATF-2, the LACFD’s Cal OES/FEMA US&R Task Force.

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