COLUMN – Avoiding panicked response to quakes
Last week, on more than one occasion, the ground started shaking; utility poles rocked from side to side; and buildings groaned as the ground under them became somewhat unstable. Traffic slowed as the very road began to roll; phones were ringing all across the island as the images of 2007 and 2014 came rushing back . . . . Barbados was experiencing an earthquake.
More than a dozen earthquakes were recorded last week –– located between 97 and 174 kilometres north-east of Barbados –– with the largest 6.4 magnitude quake occurring in the morning and felt by residents of Barbados, St Lucia, Dominica, Martinique, Guadeloupe, St Vincent, and Trinidad. Once again, the same questions were raised, with similar words of advice again given, which in my opinion was counsel which will not be truly heeded until reality rudely knocks on the doors of the complacent.
In a Press release, the Seismic Research Centre of University of the West Indies said that the Caribbean was a seismically active part of the world. The centre said the earthquakes, of the size and frequency experienced off the north-east of Barbados, were not unusual and did not by themselves suggest that anything more devastating was to come.
The centre noted that the region had had larger events in the past, and that at some point in time, once again expected to have large and possibly damaging events in the future.
Four years ago, we conducted an earthquake preparedness tour of a typical home to demonstrate just how much a family could accumulate during a lifetime of occupancy. Four years later, the ground once again begins to shake and the response is yet another mad scramble to secure everything in the house. Armchair experts once more surfaced with new predictions and facts, while religious followers stated it was the unchristian behaviour of the country that was now bringing doom to all.
Disaster preparedness is most effective when the hazard has been identified. With hurricanes and tropical storms, homeowners install shutters to protect their property. Sandbags are the preferred method to managed floodwater intrusion. Fire extinguishers and smoke detectors becomes the priority items when preparing a fire prevention and alert plan; and retrofitting the home to secure loose items including wall hangings, ornaments, bookcases, and refrigerators, is the preferred method when one prepares for the advent of an earthquake.
In light of what occurred a few days ago, I am again presenting some basic tips shared with you four years ago. I hope that this time around, common sense will take precedence over complacency, and homeowners will take the lead in implementing a home preparedness plan.
Retrofitting a home as part of an earthquake preparedness project is typically performed under the supervision of a structural engineer or similar construction professional. As the name implies, this retrofitting is performed on structures that have already been built, often on older buildings that may have been constructed well before modern standards of safe building were established.
This process can entail a number of different changes, usually based on the specific needs of individual buildings, though certain procedures are fairly common during earthquake retrofitting.
The basic goal of earthquake retrofitting is to ensure an older building is able to handle the stress and strain placed on it during a seismic event. Many older buildings were designed to simply remain upright and avoid a single force pulling on it, including gravity pulling it downward.
During an earthquake, however, forces that are horizontal to the ground can work on a building; this force is often called a lateral load. Retrofitting on a building attempts to ensure that these forces are not able to cause excessive damage to the building.
One of the most common forms of earthquake retrofitting is bolting a building to its foundation. Many older structures will have insufficient connection between the bottom of the building and the concrete foundation beneath it. Foundation bolting usually involves bolting the sill, the effective bottom of a building, into the substructure.
During an earthquake, the bottom of a building typically begins to shake and move side to side prior to the rest of the building. This means that without earthquake retrofitting, an older building may literally slide off its foundation. Many of the older houses in Barbados, usually chattel houses, are susceptible to such.
The major theme of earthquake home preparedness is retrofitting, in which the primary goal is to mitigate potentially expensive or dangerous damage to a building. It is a process that can be performed on old or new buildings, as the primary focus of the project is not the building’s foundation, but in fact the securing of any, and all lose items and fixtures installed after construction.
Here are some brief dos and don’ts for the next ground-shaking event.
If you are inside a building during an earthquake, remain calm and do not run outside. Crawl under heavy furniture or stand near a wall at the centre of the building.
Even though doorways have been recommended, not all of them are structurally sound and may only present a cosmetic appearance as a functioning opening. Watch out for falling bookcases, filing cabinets, lighting fixtures and other roof fittings, including false ceilings.
Do not use matches or any other form of open flame, as it may become an ignition source for nearby gas fittings. Stay away from glass windows and mirrors.
If you are outside, remain outside. Stay in open areas and far away from power lines and utility poles. Do not enter any building until the shaking stops.
You should only enter a building that has been designated as safe. Any other structure should be entered by rescue personnel. Buildings have been known to collapse minutes after the shaking has subsided.
If you are driving, do not abruptly stop, as this action can contribute to rear end collisions, possibly creating injuries from the incident. Pull over to the side, remain in the vehicle until the shaking subsides. If it is at night, turn on your hazard flashers to alert others on the road; and keep streets clear for emergency service personnel.
If you are in a bus, hold on to the handrails or roof rails for support. Do not attempt to jump through the windows, as this may create personal injury for you and other passengers.
Improving public safety in the event of an earthquake is an achievable goal, requiring the participation of not just Government entities, but the entire community, if the plan is to be effective. It is a concept that also requires being comprehensively introduced within the school system, so that the many misunderstandings of earthquake preparedness may be corrected. It is a concept that must also be encouraged by the Government office responsible for emergency management and disaster preparedness.
The 2015 hurricane season has so far been an uneventful period, while the opposite can be said for earthquakes occurring throughout the region. What I would not recommend is the ignoring of the uneventful hurricane season in lieu of earthquake preparedness.
It would be more advantageous to introduce an earthquake plan while at the same time maintaining your hurricane plan, since there are no accurate predictors that will determine which event will occur.
In this regard, I am recommending that you keep both plans, and not be forced to scramble the next time the ground shakes, or the wind blows off a neighbour’s roof.