7.4 Earthquake in Colombia is the strongest in the 21st century in the country: the Pacific region concentrates the highest magnitude ones in its history; background

A 7.4 magnitude earthquake with its epicenter in San José del Palmar, Chocó, shook Colombia at 7:34 in the morning on Monday, August 10. The movement had a depth of 96 kilometers and lasted close to a minute, according to the Colombian Geological Service (SGC), which recorded it with 32 seismological stations. 

The earthquake was felt in Cali, Medellín, Bogotá, Ibagué, Armenia, Pereira, and Manizales, and in Venezuela, Ecuador, and Panama. 

The magnitude took a few minutes to be established. The SGC first reported 6.7 degrees and 82 kilometers depth, then adjusted it to 6.6, and in a third bulletin, fixed it at 7.4 with 96 kilometers, the same figure calculated by the United States Geological Survey (USGS). 

With that figure, the SGC described it as the largest magnitude earthquake recorded in Colombia during the last decade.

According to the data, in the previous ten years, no tremor with an epicenter in Colombian territory had exceeded 6.5 degrees. The one on May 24, 2023, in the Caribbean Sea off Montería, reached 6.5. The one on August 17, 2023, with its epicenter in San Juanito, Meta, reached 6.1 and was the most remembered in Bogotá. 

The last 7.0 magnitude event with an epicenter in the country was on February 2, 2013, in Guaitarilla, Nariño. Nine years earlier, on November 11, 2004, one of 7.2 was recorded in Bajo Baudó, Chocó. The 7.8 Muisne earthquake in 2016 was felt in Colombia and its epicenter was in Ecuador.  

The two largest magnitude earthquakes recorded in Colombia, in 1906 and 1979, had their epicenter off the Pacific coast, in the western part of the country. 

On January 31, 1906, at 10:36 in the morning, an 8.8 magnitude earthquake shook the maritime border between Colombia and Ecuador. The SGC records it as the strongest in the country’s history and one of the largest measured on the planet. The tremor raised a tsunami that swept the beaches of Tumaco, Mosquera, El Charco, Guapi, and Timbiquí, leaving 600 people dead. 

Seventy-three years later, the same area broke again. In the early hours of December 12, 1979, an earthquake off Tumaco, of 8.1 magnitude according to the SGC and 8.2 according to the USGS, generated waves up to six meters in San Juan de la Costa. The Civil Defense counted 454 dead and more than a thousand injured, and the tsunami was even recorded on the coasts of Japan, Hawaii, and Mexico. It was one of the strongest earthquakes of the 20th century in Colombia.  

Chocó also has its own background. On October 18, 1992, a 7.2 magnitude earthquake with its epicenter near Murindó, on the fault of the same name in the middle Atrato, left ten dead, more than a hundred injured, and damage in 33 municipalities. A day earlier, a 6.7 magnitude earthquake had occurred. That event originated in the continental faults crossing the northwest. 

More background is found in the surface faults of the mountain range, where the magnitude is deceptive. On Holy Thursday, March 31, 1983, at 8:12 in the morning, a 5.5 magnitude earthquake, but at 15 kilometers depth and on the Romeral fault system, collapsed the historic center of Popayán. About 250 people died and the colonial city was left in ruins. From that tragedy came the first Colombian Code of Seismic-Resistant Constructions, the basis of the standard that currently governs construction in the country.  

Sixteen years later, on January 25, 1999, a 6.2 magnitude earthquake with its epicenter near Armenia devastated the Eje Cafetero. It was a shallow earthquake, about 17 kilometers deep, in a dense area with many vulnerable buildings. It left nearly 2,000 dead and is, to this day, the deadliest in the country’s history. Its magnitude was lower than that of this Monday’s tremor, and its human cost much higher.