Never Happen Here

Mikos Grieco

December 08, 1990|By Mikos Grieco

SO THE EARTH didn't swallow up New Madrid, Missouri, as predicted. Nevertheless the small earthquake (2.9 on the Richter scale) that Delaware experienced in October is a reminder that Eastern America is susceptible to seismic activity. Devastating quakes in Charleston, South Carolina, and in New Madrid in the 1800s caused tremendous panic, but because this century has been calm, public concern in the East has lulled.

Geologists predict that a major quake (of magnitude seven to nine) will hit somewhere east of the Rockies within the next 20 years. Moreover, it will affect an area 100 times larger than an earthquake of equal strength in California. Unlike the West, where fault-shattered rock tends to dull the spread of shock waves, the East is composed of relatively solid rock through which waves travel more easily.

The Delaware earthquake is evidence of this phenomenon: Although small, it was felt in parts of Pennsylvania and New Jersey. So although Maryland itself is labeled as either a 0 or a 1 on a national seismic-risk scale of 0-4, a major earthquake virtually anywhere in the Southeast would hit the state hard.

Eastern states are not prepared for a major earthquake. A Seismic Provisions Review Committee of the American Society of Civil Engineers concluded over a year ago: ''Seismic risk in Maryland is not taken seriously at all by the profession or the public.'' The committee issued a series of suggestions detailing steps to prepare for a big one.

Much of the damage from earthquakes is caused by the ''failure'' of buildings, and most of the buildings that collapse are of unreinforced masonry -- bricks, cinder blocks and under-reinforced concrete. The committee suggested that old structures built in this way should be strengthened and that new construction follow seismic design requirements. Retrofitting old buildings may involve securely anchoring the walls to the foundation floors and roof. New structures must be well-connected and ductile -- able to withstand and absorb the lateral forces of an earthquake.

The cost of retrofitting varies. To prepare for an earthquake, a Rodgers Forge homeowner, for example, could spend anywhere from several dollars to secure his water heater and other large objects to several thousands for a complete structural retrofit. Making new buildings accord with seismic design would cost an extra one to two percent of the total construction expense.

These costs are not overwhelming, but homeowners, builders and the state are unlikely to accept them during rough economic times. Perhaps legislation can encourage them. Homeowners should receive tax write-offs for retrofitting. The state could mandate adherence to seismic codes in the bids it lets. These costs will probably trickle down to the public, but it must be remembered that tax-payers will pay for disaster relief in the event of an earthquake, and the amount of this tax -- as well as loss of life -- will obviously be mitigated if fewer buildings fail.

Priorities must be set. Fire stations, hospitals and other buildings that have to operate during and after a disaster must be strengthened. Schools and other high-occupancy structures as well as nuclear and chemical plants must be secure. In short, the state should assess the need to retrofit based on the consequences of failure.

The committee that reviewed seismic provisions in Maryland, chaired by Nicholas P. Jones, of the Department of Civil Engineering at the Johns Hopkins University, concluded that design practice for dams, bridges and signs is carried out well. Moreover, the number of bridge-inspection teams has recently been increased from four to six.

But it found that requirements that public structures such as schools be ''designed to the Basic Building Code, including adherence to the seismic requirements,'' are loosely enforced, at best. In most private buildings, it reported, ''seismic requirements are not . . . considered'' due to a perception that they are not important or a lack of funds. Most of the low buildings in Baltimore, such as row houses, are not only composed of unreinforced masonry, but are dilapidated and weak.

Officials of the Public Service Commission, the Development Planning Department, the Department of General Services, the Baltimore Public Buildings and Grounds Department, the Codes Administration Department, and even an architect of the Public School Construction Program all betrayed the fact that the seismic building codes are not taken seriously. Some said they hadn't heard of the committee's recommendations; others cited the state's low seismic risk.

L Some of the committee's other recommendations are being met.

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