The depths of the Earth maintain a continuous movement of tectonic plates, even though the surface appears stable. This underground activity is the force behind major geological phenomena.
A specific type of displacement, known as “subduction”, was the cause of the tremor that hit western Colombia on the morning of August 10, 2026, causing a strong earthquake.
The earthquake, with a magnitude of 7.4, according to information from the United States Geological Survey (USGS), had its epicenter located in the municipality of San José del Palmar, in the department of Chocó, at a considerable depth of 107 kilometers.
Authorities reported that the event resulted in at least 169 deaths, according to Reuters data citing local sources. In addition to the fatalities, there were building collapses and extensive material damage in several cities, including Pereira, Manizales and Cali.
Julio Fierro Morales, general director of the Geological Survey of Colombia, described what happened as “the strongest earthquake felt in the country in the last decade”, highlighting the intensity of the shock.
The seismic activity in that area, as explained by the agency, is a reflection of the natural tectonic dynamics of western Colombia, linked, among other processes, to the movement of the Nazca plate.
The concept of “subduction” describes the geological process in which one tectonic plate bends and sinks, sliding beneath another.
Germán Prieto, professor at the Department of Geosciences at the National University of Colombia, highlights that the Colombian territory is located in an area of confluence of important tectonic plates: the Nazca, the South American and the Caribbean.
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The seismic shock recorded on August 10 originated from the sliding of the Nazca plate, located in the Pacific Ocean, which moves under the South American plate towards the east, where Colombia is located, as detailed by the professor.
The subduction mechanism also explains why this earthquake is not directly related to the two tremors that occurred in Venezuela on June 24.
Colombia is a nation with intense seismic activity, a factor attributed to the convergence of tectonic plates, which include the Caribbean. These plates, which make up the Earth’s outer, rigid layer, oppose a warmer interior.
Prieto, in his explanations, compared the Earth’s structure to an egg, having a malleable interior and a rigid shell.
The planet’s rocky layer, according to the expert, is fragmented like a puzzle into several pieces. The movement and interaction between these parts are responsible for generating earthquakes.
The depth of earthquakes and their influence on damage
Despite its significant magnitude, the earthquake that hit Colombia on August 10 was not necessarily the most destructive in the country’s recent history.
Magnitude, in fact, is just one of the variables that determine the devastating power of an earthquake.
Learn more: Why do giant earthquakes hit neighboring countries, but rarely Brazil?
Another crucial element is the depth of the event. Sergio Barrientos, director of the National Seismological Center at the University of Chile, explained that the tremor was “quite deep, which means that the waves reached the surface attenuated.”
The seismologist clarified that this does not qualify as a “shock earthquake between tectonic plates”, unlike those that occur in places such as Venezuela, Peru, Ecuador or Chile, which generally have more superficial foci.
Depth was, in fact, one of the main factors that resulted in the devastating power of the 1999 earthquake in the coffee region of Colombia, with an especially severe impact on the city of Armenia.
That year, the earthquake had a magnitude of 6.2, but, unlike the recent one, its epicenter was much shallower, causing the deaths of around 1,200 people, according to official records.
The August 10 event occurred close to that same area, but had Pereira, located 45 kilometers from Armenia, as one of the hardest hit cities.
Seismic activity in western Colombia is driven by the continuous subduction of the Nazca plate, which advances beneath the continent at a speed of 55 to 60 millimeters per year, accumulating pressure and energy that is eventually released in the form of earthquakes.
Colombian specialist Germán Prieto details that the subduction process is intrinsically linked to the boundaries of tectonic plates, which can be classified as divergent, convergent or transforming.
In the case of the August 10 earthquake, the boundary between the plates was convergent, indicating that they move in opposite directions and one of them, typically the oceanic one, dives under the other.
Prieto also adds that this type of phenomenon is a common occurrence in several regions of the planet. He cites the “Pacific Ring of Fire” as a notorious example of multiple convergent and subduction boundaries, directly associated with the occurrence of earthquakes and chains of volcanoes.
This vast region extends from Chile and Peru to Colombia, continuing through Central America, Canada, Alaska, Kamchatka, Japan, the Mariana Islands, and ending in New Zealand and Tonga. All of these areas are characterized by active volcanoes and frequent earthquakes.
Is there a connection between the earthquake in Colombia and the tremors in Venezuela?
The president of the Venezuelan Society of Geologists, Feliciano de Santis, stated that there is no direct relationship between the earthquake in Colombia and the recent tremors in Venezuela.
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De Santis explained that although Venezuela and Colombia share the South American and Caribbean plates, the link between the earthquakes is “very indirect.”
He warned that it cannot be inferred that “every time there is an earthquake in Venezuela, there will be another one there afterwards”, even with the two countries inserted in a system of interconnected plates.
To illustrate the interconnection of the plates, De Santis used the analogy of “the peel of a tangerine that breaks in several places, and all the pieces are interconnected.”
In Venezuela, according to the expert, the fault system is different, and the “Colombian system is deeper”.
This depth even contributes to mitigating damage, as De Santis added. He explained that in Venezuela the systems are more superficial, with the plates sliding laterally, while in Colombia there is a compression system where one plate dives under the other.
In essence, it is a tectonic model that differs significantly.
Colombia amid constant seismic activity
Due to its strategic location in the interaction zone of the Nazca, Caribbean and South American tectonic plates, Colombia is recognized as one of the most seismically active nations in Latin America, with a history of large earthquakes.
On average, the country records approximately 2,500 earthquakes per month, which is equivalent to around 80 tremors per day.
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Most of these events, according to the Geological Survey of Colombia, are of low magnitude, being imperceptible to the population and recorded only in technical reports.
The country’s inclusion in the Pacific Ring of Fire, a vast region that surrounds the Pacific Ocean and concentrates most of the global seismic and volcanic activity, is also a relevant factor.
Among the largest seismic events ever documented, the earthquake of January 31, 1906, with a magnitude of 8.8, whose epicenter was located on the Pacific coast, between Colombia and Ecuador, stands out.
The magnitude of the force released by this earthquake was such that it caused a tsunami that extended across much of the Pacific coast.
Another notable event was the 1979 earthquake, of magnitude 8.1, which occurred off the coast of Nariño.
In recent Colombian history, some earthquakes have caused severe impacts, such as the one in 2004, with a magnitude of 7.2, or the La Vega earthquake in 2012, which reached a magnitude of 7.1.
However, magnitude alone does not always define the total impact. Other earthquakes, with less power, caused great devastation in the country due to their proximity to populated areas or the fragility of buildings.
Notable examples include the 1999 Armenia earthquake, which resulted in 1,185 deaths, and the 1994 Páez earthquake in southwestern Colombia, which also caused more than 800 deaths.