Two powerful earthquakes struck Venezuela’s northern coast on Wednesday, killing more than 180 people as part of a seismic phenomenon known as “double earthquakes.” The two earthquakes were the most powerful in Venezuela in more than a century, leaving the country facing widespread destruction.That’s why the damage is so rapid and severe.When two earthquakes occur simultaneouslyA double earthquake occurs when two earthquakes of similar magnitude hit the same area within a short period of time. A 7.2-magnitude earthquake first struck on Wednesday night. Just 39 seconds later, an even stronger 7.5-magnitude earthquake struck, according to the U.S. Geological Survey.The successive attacks left almost no time for people to react. Buildings collapsed in the capital Caracas and surrounding areas. More than 1,500 people were injured and thousands more were missing. Officials said the coastal strip of La Guaira in northern Caracas suffered the worst casualties and structural damage.Most earthquakes follow a more familiar pattern: a main shock followed by a series of weaker aftershocks. Christine Goulet, director of the U.S. Geological Survey’s Earthquake Science Center in California, told The Associated Press that twin peaks are less common and behave differently, although they can occur anywhere in the world.A fault line with a violent historyThe twin peaks point to the geologically complex fault structure beneath Venezuela. The Bocono Fault stretches about 500 kilometers along the Venezuelan Andes and has a long record of seismic activity. Just in September 2025, a dual earthquake measuring 6.2 and 6.3 on the Richter scale struck the area west of Caracas, killing at least one person and injuring more than 100 people.This week’s earthquake was triggered by movement at the boundary where the Caribbean and South American plates meet. The Caribbean Plate north of Venezuela is moving eastward past the South American Plate at about two centimeters per year.“The displacement is huge,” Goulet was quoted as saying by the Associated Press. “It’s similar to the San Andreas Fault.”The rupture was a shallow strike-slip faulting event, meaning the two rocks slid horizontally past each other instead of one moving onto the other. Goulet noted that such movements are not automatically more destructive. “More vertical movements may cause greater damage,” she said, adding that factors such as rupture length also play an important role in determining the scale of the damage.There is relatively little activity at the Caribbean-South American plate boundary, said David Nall, associate dean of the University of South Florida’s College of Marine Science. USGS records show that there have been only seven earthquakes of magnitude 6 or above in the area over the past century.A region no stranger to earthquakesSince 1900, at least five earthquakes of magnitude 7 or greater have occurred in northern Venezuela or along its coastline. The most recent major earthquake in living memory was the 6.6-magnitude quake in July 1967, which killed hundreds of people.Caracas resident José Vitriago, who was barely two years old at the time, still remembers the devastation. “Our house is broken,” he told state broadcaster Venezolana de Televisión. He said Wednesday’s straitjacket was “terrible, horrific.”In March 1812, Venezuela’s worst recorded earthquake occurred on the same Bocono fault system. It is estimated to have killed around 30,000 people.Earthquakes remain unpredictable, but the risk of aftershocks remains. The U.S. Geological Survey estimates that there is a 99% chance of at least one magnitude 4 aftershock in the next week, and a 24% chance of a magnitude 6 aftershock.Venezuela does not have an earthquake early warning system, which uses ground-based sensors to detect initial seismic waves and alert residents before the strongest shaking arrives. On Wednesday, two earthquakes struck almost without warning.“There was basically no time to evacuate, which was very distressing,” Goulet said. “It’s so unfortunate.”