The second earthquake that hit Venezuela on Wednesday started rumbling before the first had even concluded.Their onsets were separated by just 39 seconds.
Limited time: Save 25% on NBC News subscriptionGet exclusive reporting, live Q&As and ad-free reading.The U.S.Geological Survey has described the pair of earthquakes — a 7.1-magnitude and a 7.5-magnitude — as a doublet sequence, a phenomenon in which two temblors of similar magnitude strike roughly the same area at around the same time.
“The seismic waves from the first one weren’t done yet when the second one happened,” said Harold Tobin, the director of the Pacific Northwest Seismic Network and a professor at the University of Washington.Follow live coverage here.A heavily damaged apartment building Thursday in Catia La Mar, Venezuela.Juan Barreto / AFP via Getty ImagesIt’s not rare to have two earthquakes in relatively short succession.
But in this case, the rapid, back-to-back shaking likely led to more collapsed buildings and other destruction.At least 188 people were killed and at least 1,520 were injured, with more than 150 still missing.The first earthquake “will probably have weakened some buildings or structures,” Tobin said.
“Then collapses would happen during the second earthquake, even if they made it through the first one.” A 7.5-magnitude temblor is about three times bigger than a 7.1, since the Richter scale is logarithmic.(Each whole number is 10 times bigger than the previous.) The doublet pattern took place on a tangled system of faults near San Felipe, Venezuela.
The zone is so complex that it will take more time for researchers to understand precisely which faults within it ruptured Wednesday.Maria Beatrice Magnani, a professor of seismology at Southern Methodist University, who mapped faults in Venezuela in the early 2000s, said the ruptures happened along a boundary between the South American and Caribbean tectonic plates, where the two are essentially sliding l...