The magnitude 7.4 earthquake of August 10, 2026, with its epicenter in San José del Palmar (Chocó) at a depth of 103 km, brought down dozens of buildings in Cali. The first findings agree on three causes: the buildings that collapsed were not built to the NSR-10; many were relatively flexible frames, designed when the city's hazard was believed to be lower; and the soil amplified the shaking in some areas.
The earthquake
According to the Colombian Geological Survey (Servicio Geológico Colombiano), it struck at 7:34 a.m. and was of intermediate depth, in the zone where the Nazca plate sinks beneath the South American plate. The nearest stations recorded between 90 seconds and 2 minutes of shaking, and it is the third-largest earthquake in the country's history. Although it was deep, it was felt strongly across the west of the country: at magnitudes like this, the energy does not have time to dissipate before it reaches the surface.
What was seen in Cali
Universidad del Valle reported 54 collapsed buildings in a first survey and 34 more identified later (Caliescribe). By mid-August, the city government had 60 buildings slated for demolition and more than 4,000 of 14,000 properties inspected, and announced a forensic investigation with the Sociedad Colombiana de Ingenieros and Universidad del Valle to establish the cause of each collapse (90 Minutos).
Why they collapsed
Engineer Albert Ortiz, director of the School of Civil and Geomatic Engineering at Universidad del Valle, found a pattern: many of the collapsed buildings were moment-frame systems, relatively flexible structures, built when Cali's seismic hazard was characterized as lower than what is known today. The 1984 code allowed more flexible designs. Today the NSR-10 places Cali in the high hazard zone, with Aa = 0.25 (table A.2.3-2). The measurements also showed amplification of the shaking, with differences of up to seven times between parts of the city.
By contrast, the president of Camacol, Guillermo Herrera, reported that buildings built to the NSR-10 had not collapsed as of that date (Semana). It is a preliminary finding: the forensic investigation will establish the causes case by case.
What it teaches
First, that the date of construction matters: a building designed to an earlier code may not be prepared for what is now known can happen. Second, that a flexible frame without walls builds up large displacements between floors; the NSR-10 limits them to 1% of the story height (see story drift). Third, that the soil can matter as much as the structure: that is why seismic microzonation studies exist, and why the geotechnical study defines the soil profile used in the design.
And on the coast?
Barranquilla and Cartagena are in the low hazard zone, with Aa = 0.10 (see seismic hazard on the Caribbean coast). But part of the region's buildings predate the NSR-10, and in many of them the salt air has deteriorated the reinforcement. The vulnerability assessment of chapter A.10 is the way to find out what condition a building is in (see existing buildings).
Sources: Servicio Geológico Colombiano; Universidad del Valle, cited by Caliescribe (October 2, 2026); Cali city government, cited by 90 Minutos (August 19, 2026); Camacol, cited by Semana; NSR-10, table A.2.3-2. The figures are those reported on those dates and may have changed.
Frequently asked questions
Why did buildings collapse in Cali in the August 10, 2026 earthquake?
According to the first analyses by Universidad del Valle, many were relatively flexible frames designed to earlier codes, when Cali's hazard was believed to be lower, and the soil amplified the shaking in some areas. The official forensic investigation will establish the causes case by case.
Did buildings built to the NSR-10 collapse?
According to Camacol's preliminary report, buildings built to the NSR-10 had not collapsed.
