What is happening with the Bucaramanga Seismic Nest?

UOnce again on Wednesday afternoon a seismic movement was perceived in Santander. There are already seven events of magnitude greater than 4.0 that have occurred in the department in the last two weeks.

The continuity of these tremors has set off alarms. The citizens themselves say that they have never before felt that “the earth moved so much.” They are uneasy. And although up to now there have been no affectations, the Disaster Risk Management Units, the relief agencies and even the communities themselves are attentive to any threat they represent.

The Bucaramanga seismic nest is the second zone of greater intermediate seismicity in the world. It is very common that at this point two low magnitude earthquakes are recorded per day; even once a month a movement greater than 4.5 magnitude is reported.

However, the people of Santander have lived a very busy month of July, so given the unusual nature of the movements, the geologist Francisco Velandia, associated with the Geology School of the Industrial University of Santander, explained that, although it is not well known what’s up, there are some hypotheses.

“The nest is one of the most active in the world. We know that. But why it is, we do not know very well. It is a relation of tectonic plates that have sunk and that are very cold and deep. So there are experts who assure that it is the friction between two plates and others who say that it is a plate that is breaking, is tearing, “said Velandia.

Also read: These are the 12 strongest tremors recorded in recent years in Santander

There are two geological faults in the region that could also generate seismic events: Bucaramanga fault – Santa Marta fault and Suárez fault. However, professionals such as Carlos Lozano, coordinator of the Seismological Observatory of the University of Santander, Udes, all the earthquakes that the bumangueses have perceived have been recorded in the nest.

“From the depth we can know that they did not come from the faults. If the movements came from there, they would be much less deep and could cause some damage,” he said.

Germán Ojeda, PH.D. In geophysics and manager of Subsuelo 3D SAS, he assured that the exact and precise cause of why there are so many earthquakes in Los Santos is not yet known because human technology has not reached these depths.

“All the information that we have from there is indirect information. It is not possible to make a well that penetrates 150 kilometers to see what is happening with a camera. There are several hypotheses, the dehydration of some rocks or a clash between plates. But there is no need to be alarmed, ”explained Ojeda.

This same call was made by Marta Calvache, director of Geo-threats of the Colombian Geological Service, SGC, who asked for calm combined with preparation.

According to her, we have to look beyond the earthquake because it is not only important for the earthquake to occur and its magnitude, but also how it is designed, how I build and how these buildings resist.

“The earthquakes that have occurred in Bucaramanga, even the one in March 2015, are far below what the construction norm that the buildings must withstand says. So it is true that the movement feels strong and scares, but the earthquakes are much smaller than a construction can withstand, “said the SGC director of Geo-threats,

Experts also emphasize that “at this time and with the technology of the 21st century, no one can predict an earthquake. The earthquakes that are felt in Bucaramanga come from El Nido and it is good because, although the tremor is very large, it always comes from a very deep place. We Bumangueses must be calm but educated, “said Ojeda.

Carlos Fernando Lozano Lozano, director of the Seismological Observatory of the Colombian Northeast of the University of Santander – Cdmb, assured that these seismic events that have occurred recently have the particularity that have originated in the so-called ‘Bucaramanga Seismic Nest’, which corresponds to a concentration of seismic events that occur at an average depth of 150 kilometers.

However, the expert was clear in pointing out that the frequency and magnitude of the telluric movements is very strange, since “the seismic focus located in this region is very dynamic. The average is almost 20 events a day. However, most have a low magnitude. ”

In specific figures, the National Seismological Network of Colombia highlighted that during 2019 11,563 seismic events occurred with an epicenter in the territory of Santander. Of these, 64 were of magnitude equal to or greater than 4.0.

What to do before an earthquake?

Luis Ortega, head of the Bucaramanga Disaster Risk Management Unit confirmed that so far there have been no emergencies or damages in the city.

The call is to remain calm and for citizens to take preventive actions.

That is, the main thing is to verify that the infrastructure of the places we inhabit are earthquake-resistant, we must also have an emergency briefcase that contains a first-aid kit, flashlight, radio with batteries, water, non-perishable food, clothing, formulated medicines and whistle.

The official also suggests not running while the earth is moving, not using vehicles, moving away from windows and falling objects, moving away from trees and electrical networks, not using lifts, and once the shaking is over go to safe places or points. previously established meeting points.

In the event that any affectation is evidenced, damages must be reported to organizations such as the Red Cross, Civil Defense, Fire and National Police.

On the other hand, it is suggested to have a family emergency plan.

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