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Volume 27, Issue 4

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October 29, 2007

Preparing For Earthquakes

Written by  Vicky Rathje
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Earthquakes. We have been hearing a lot about them recently and we will undoubtedly hear more. Geologists warn that we are in a period of increased seismic activity and that significant earthquakes are likely to occur throughout the United States before the turn of the century. As much as 90% of this country’s population lives in seismically active zones.

Tremors in the United States are not confined to California and Alaska. In total 39 states have active faults. The Northwest, Intermountain-region, the Midwest, the Southeast and the Northeast are all exposed to seismic risk.
Many people believe that moderate earthquakes relieve the pressure building along fault lines, reducing the possibility of a larger earthquake. This is simply not true. To the contrary, seismologists warn that increased activity often precedes major earthquakes.

After the recent San Francisco earthquake measuring 5.2 on the Richter scale, Andy Michael, a USGS geophysicist warned “The stress is building up in the earth and we’re going to start getting large quakes. It (the August 8, 1989 quake) should serve as a reminder to prepare.

Insurance Industry estimates indicate that a major earthquake in the United States, regardless of its location, is likely to cause damages of up to $50 billion. This would drain the insurance industry of half of its reserves. As a result many insurance companies would become insolvent.

Non-structural damages resulting from an earthquake are likely to comprise as much as 75% of direct damages. Fire being the greatest threat following a destructive earthquake claiming as much as 50% of losses. Damage to computer systems, death and injury and related damages are likely to contribute up to 25% of losses.

EARTHQUAKE LIABILITY

According to the Association of Bay Area Governments recent study, Earthquakes may not be considered an “act of God” in the legal sense.

“Although the earthquake event is perhaps the epitome of an “act of God” the fact is that earthquake occur in California. The damage resulting from an earthquake may be foreseeable and under some circumstances can be mitigated, at least partially. The research concludes that this defense may work in only two very limited situations.

  • The earthquake was of such type or size as to be unforeseeable and the business did not act negligently with respect to dealing with a foreseeable earthquake.
  • The earthquake was foreseeable, and the defendant took all reasonable actions to prevent harm, but nonetheless damage still occurred.

Expanding on the aspect of liability, Gerald Stephens, President of the Society of Chartered Property and Casualty Underwriters comments:

“Once it has been established that a business or public entity has failed to make a reasonable effort to prevent loss, breach of duty creates the basis for claims of negligence. The issue then becomes not whether the company is liable, but the extent of the damages and the amount of compensation that is necessary....No one should take comfort in the belief that only great earthquakes produce big liability losses. Businesses and public entities are also likely to be held liable in smaller events. The reasoning is that smaller quakes are more foreseeable, making defendants more responsible.”

Preparing for a devastating earthquake can make disaster recovery an easier task.

LOSS REDUCTION TECHNIQUES

In addition to traditional forms of preparation, such as structural bracing, storing emergency supplies and securing equipment, innovative protection methods are being implemented at progressive companies dedicated to loss prevention.

These techniques integrate advanced seismic detection technology with innovative engineering applications to automatically initiate safety and damage mitigation procedures, before the damaging wave of the earthquake strikes.

Several seconds warning prior to the impact of a major earthquake can give valuable lead-time to automatically initiate the shut-down of utilities, computer systems, industrial processes and hazardous materials.
In addition, an alarm can be sounded alerting building occupants to seek shelter prior to the impact of the earthquake.

Intelligent seismic sensors are able to detect the earthquakes “P” waves. These waves travel nearly twice as fast as the destructive “S” and “L” waves released during an earthquake. When these sensors detect a “P” wave at or above a certain degree of force, the system initiates a shutdown of selected utilities and systems, contains hazardous materials, and activates a prerecorded message which instructs the building occupants to stay calm and take cover. Messages can also be programed to aid in disaster procedures following the quake.

HOW MUCH TIME WILL IT GIVE?

The amount of advance warning the seismic alarm will give people depends on the building’s distance from the epicenter of the quake and can be several seconds before the temblor hits.

According to Wilfred Iwan, a Professor of Engineering at Cal Tech and an expert on earthquake preparedness, even one second’s notice can be a big plus, though “It depends pretty much on your conditioned response. You have to ask yourself, what would I do with those one or two seconds.”

According to Paul Flores, Director of the Southern California Earthquake Preparedness Project, “Getting under a heavy piece of furniture in a couple of seconds is the best recommendation you can give people.” This advice was dramatically proven to be sound during the 1985 earthquake in Mexico City, when desks were all that kept floors of buildings from collapsing on one another like stacks of pancakes.

REACTS ONLY TO EARTHQUAKES

The alarm is calibrated to react to a particular ground acceleration (0.15G-0.25G) at the specific frequency inherent to earthquakes (.5HZ-.15HZ). It cannot be triggered accidentally by rotating equipment, blasts, vehicles, or industrial vibrations.

Although these other kinds of vibrations can have similar acceleration rates, they do not have to have the same frequency as earthquakes. These instruments can be utilized in all types of environments including heavy manufacturing or industrial locations without concern for false alarms.

OVER APPLICATIONS OF THIS TECHNOLOGY

The sensor technology was developed by the same team of researchers responsible for the first commercially available Strong Motion Accelerograph, the production of the Apollo Lunar Seismometer and Tidal Gravity System, recorders for the World Wide Standardized Seismograph Network, and the production of the Ranger Lunar Seismometer based on the original design by Caltech.

APPLICATION OF PRACTICAL ENGINEERING METHODS FOR LOSS CONTROL

The scope of applications for Real Time seismic safety equipment:

  • Containment of hazardous materials
  • Protection of lifeline
  • Sequential shutdown of Computer Centers, potentially vulnerable industrial processes, machinery, conveyor lines
  • Automatic seismic emergency annunciation alarm systems
  • Utility shutdown, including gas, oil, water, and electricity

SUGGESTED ACTION FROM THE NATIONAL INSTITUTE OF BUILDING SCIENCES

According to the Building Seismic Safety Council, in areas where earthquake hazards are high, structures are vulnerable to post-quake effects such as uncontrolled fire conflagrations, hazardous material spills, electrocutions, and non-structural failures. The council suggests that such structures “be provided with shutoff devices for all utilities, including oil, gas, water, high temperature energy, and electrical supply.

EARTHQUAKE MITIGATION IS COST EFFECTIVE

The Center for Earthquake Studies stresses that mitigation programs like those recommended by the Council are “extremely cost effective.” The center asserts that, “By preventing most of the damages and losses of future earthquakes, these programs eventually return hundreds and thousands of dollars for every dollar invested.”

PREPARE BEFORE THE DISASTER

Geologists warn that we can expect a greater number of damaging earthquakes in the highly populated, industrial centers of North America before the turn of the century. Now is the time to prepare. In addition to avoiding direct losses through property damage and human losses, the avoidance of costly down-time can help to return to normal business functions as quickly as possible following a quake.

Preparing for a disaster by analyzing what effect this potential disaster may have, and taking prudent action to minimize the losses will help to ensure the survival of an organization.


Author - Vicky Rathje, Technical Consultant, Earthquake Safety Systems

This article adapted from Vol. 2, No. 4, p. 22.

Read 1966 times Last modified on October 11, 2012