Earthquake risks in the United States include some of the same that took a deadly toll in Haiti and Chile.
The tragedy of earthquakes, first in Haiti and now Chile, continues to be played out on our television screens. While most Americans look at this situation as being that of a third-world country, the risks that we live with today include some of those that have taken their deadly toll in Haiti. That is the presence of unreinforced masonry buildings here in the United States. As the Chile earthquake shows, even though there may be strong building codes many older buildings remain at risk.
Most people believe that we have modern building codes that are properly enforced. These codes apply to new construction and were enacted based on lessons learned from previous emergencies and disasters. As a fire official once told me, “Every line in the fire code is written in blood.” Without the experience of a disaster we are slow to change our fire or building codes.
However, the “as built” infrastructure remains as it was constructed before engineers had design information or modern seismic standards were put in place. Therefore in the majority of communities in the United States there remains a legacy of buildings that are not capable of surviving a significant earthquake without serious damage or possible collapse.
These unreinforced masonry buildings may date from before the turn of the century, well into the 1930s and possibly beyond. Look in any older section of downtown areas throughout Illinois and the United States and you will see historic brick buildings that remain and are being used as businesses and homes.
Ask any seismic engineer and they will tell you that these unreinforced masonry buildings are not seismically stable in an earthquake. Depending on the soils that those buildings are constructed on it may not take a significant earthquake to damage or destroy this class of buildings.
While California has been addressing the issue of unreinforced masonry buildings for many decades there has been no such comprehensive effort in the rest of the states with earthquake hazards.
People seem to think that it’s only California that has a serious earthquake problem. Other West Coast states like Washington and Oregon also have significant earthquake risks. Other Western states with earthquake hazards include Arizona, Nevada and Idaho.
The New Madrid Fault zone can have earthquakes that impact up to seven states: Illinois, Indiana, Missouri, Arkansas, Kentucky, Tennessee and Mississippi. Like the Haiti earthquake, it’s been almost 200 years since the last great quake on that fault.
The Northeast is also not immune from earthquakes. There’s a long history of recorded earthquakes from the 1600s up until today. New York, Massachusetts, Rhode Island, Vermont and New Hampshire are all states that have had earthquake damages in the past.
Simply conducting an inventory of unreinforced masonry buildings and documenting the number and location of them will help in educating building officials and building owners to the threat that exists.
Our typical path to solving an infrastructure problem is to wait and only “fix it on failure.” When the bridge, road or building does fail we will act astonished as though we didn’t expect it to happen. While the timing of an earthquake may be a surprise, the results of having unreinforced concrete buildings being used on a daily basis and their vulnerability to ground shaking can only be called a “predictable surprise.”
A recent early morning earthquake in Illinois can either be a wake-up call to take action, or a snooze alarm event. When the next major quake does happen somewhere other than California we can all act surprised.
[Photo courtesy of Mass Communication Specialist First Class Joshua Lee Kelsey/U.S. Navy.]