There is a region in central Santander that shakes and rattles 365 days of the year. Perched on a plateau overlooking the Chicamocha Canyon, the town of Mesa de los Santos is Colombia’s most seismic place with some 40 tremors registered each day. At the epicenter of the “Bucaramanga Nest” of fault lines, Mesa de los Santos, from ground level is a picturesque resort community with a manicured golf course and wooden chalets for weekenders.
Even though the inhabitants of Mesa de los Santos have grown used to having the Earth move beneath their feet, for those who live in large cities, such as Bogotá and Medellín, the thought of an earthquake is always an important concern. The last major quake to hit Colombia took place on January 20, 1999 when a 6.1-magnitude struck the central coffee region. Besides severe structural damage to the towns of Armenia and Pereira, the quake resulted in 1,200 deaths and a quarter of a million people were affected with economic losses estimated at USD $1.2 billion.
Three lithospheric plates converge in Colombia: the Nazca, Cocos and Pacific. This constant telluric action creates multiple pressure points, as is the case at Mesa de los Santos, where the nation’s geological agency INGEOMINAS registers daily quakes. Ranging between 1 and 3 on the Richter scale, most of the movement swells from 70 or more kilometers below the earth’s surface.
But some deep earthquakes make themselves felt across this nation, as was the case on October 1, 2012, when a 7.1-magnitude earthquake shook Popayan and was felt in the capital Bogotá and Barranquilla on the coast. There was no loss of life or serious damage, unlike a similar episode three decades earlier, when the “white city” was destroyed in 17 seconds. Most of the quakes which strike the southern part of the country originate from the “Cauca Nest,” and tend to be more superficial.
The Popayan earthquake of March 31, 1983 marked a turning point for seismic research in this country. Until that fateful Good Friday when the Pubenza fault snapped, the nation didn’t see the need for strict earthquake controls. Known for its Holy Week activities, the earthquake struck when the city had more visitors than usual, and many of its 115,000 inhabitants were attending religious services in colonial buildings made of adobe and stone. The focal depth of the Popayan quake was only 10 kms. Many of the first victims died when the Cathedral dome collapsed. The death toll of the 1983 Popayan quake stands at 300.
Even though seismologists in Colombia pay close attention to where the next possible movement will happen, Bogotá remains vulnerable given its location near the two major fault lines running north/south along the eastern Andes cordillera. Plus there’s the issue that most of the capital is built on the sands of a dried out lake. In 1917, Bogotá experienced an overwhelming 7.3-magnitude earthquake. The city was much smaller then, but the clay-like foundation underground played a large part in the devastation.
Because of high risk for seismic activity, Bogotá has its own building code, separate from national regulations. However, many informal builders don’t follow these regulations because it means spending more on materials. The makeshift homes built on the side of the mountains are at serious risk during a natural disaster.
The Bogotá Office of Prevention and Emergency Attention works with major public institutions to develop “master strategies” so that people know what to do in the event of an earthquake. In the case of a major quake, you should first make “a safe house” by moving large objects or furniture. Secondly, initiate a prearranged emergency plan with your family members, and prepare an emergency kit that includes a portable radio, flashlight, bottled water and other items. With the help of someone who knows your building, find out if it can resist an earthquake and identify the places that can offer the best protection.
During strong tremors, go to the safest area in your home by taking cover underneath a sturdy table and getting in the fetal position. It’s also important not to get close to exterior walls, but remember that windows, stairs and architectural foundations are usually the first to crumble.
When the quake ends, be sure to evaluate the state of everyone’s health, disconnect the electricity and close the water and gas valves to avoid leaks that can result in flooding and fire. During a natural disaster, communication is key.
Even though we hope there is no “big one” for Bogotá, the message from Colombia’s most seismic town – Mesa de los Santos – should be clear: We can never be too prepared, nor too alert when dealing with earthquakes.