Colombia earthquake has killed at least 132. Research helps explain why it was so destructive

A powerful earthquake struck near San Jose del Palmar in Colombia, resulting in at least 132 deaths and significant damage to cities like Cali, Manizales, and Pereira. The United States Geological Survey determined the earthquake was primarily caused by strike-slip faulting at a depth of about 110 kilometers. Strike-slip earthquakes occur when two blocks of Earth's crust slide horizontally past each other.

This event follows a recent series of earthquakes in Venezuela that may have destroyed or damaged over 58,000 buildings and claimed thousands of lives. While it is too early to determine if the Colombian and Venezuelan earthquakes are connected, there is evidence from Australia suggesting nearby earthquake faults can transmit stress to one another.

The study of reinforced concrete structures in Colombia has revealed that many buildings have thin concrete walls, typically 7 to 10 centimeters thick, with only a single layer of brittle steel reinforcement. This design is common in the Latin American region and is not unique to Colombia. In 2011, a magnitude 6.3 earthquake caused widespread damage in Christchurch, New Zealand, where most reinforced concrete buildings performed well due to design principles introduced post-1980.

However, some collapses were attributed to buildings designed before these principles were adopted, such as the Pyne Gould building, which failed due to low steel reinforcement in thin concrete core walls. Similar practices exist in Australia, where the Australian Standards for Concrete Structures were revised in 2018 to prevent structural failures.

The article emphasizes the need for improved building practices to mitigate the risk of destructive earthquakes in these regions.