The seismic doublet like the one recorded in Venezuela, a less common phenomenon than that of a main earthquake followed by minor aftershocks, occurs when the rupture of a fault triggers that of another segment of the same or a very nearby fault.
Lucía Lozano, a seismologist with the Spanish National Seismic Network, explained to EFE that The seismic doublet occurs when “two earthquakes of very similar magnitude coincide, very close in time and very close in space.”
Those in Venezuela, of magnitudes 7.2 and 7.5, occurred 40 seconds apart, 23 and 28 km away from the town of Yumare, according to the United States Geological Survey (USGS, in English).
“It is not so common. It is more common for there to be a main earthquake that ruptures along an entire fault and for all the tension that is accumulating in the crust to be released in the form of a rupture,” said the seismologist.
“But this,” he added, “can sometimes trigger other earthquakes in another segment of that same fault, or in a very nearby fault, as Venezuela has now experienced. What it indicates is that all that rupture zone is very complexwith interaction processes between the faults, and that is why two very large earthquakes like this can be triggered.”
Although it is not frequent, among other cases of seismic doublets, the expert mentions another one in Venezuela, “two earthquakes very close together in September 2025, but with smaller magnitudes, 6.2 and 6.3”, and one in Pakistan in 1997, with earthquakes of 7.0 and 6.8.
1 / 27 | Strong earthquake in Venezuela: the images after the earthquake that was felt in Puerto Rico. A rescuer gives directions at the place where a building collapsed after the earthquake that occurred in Caracas on June 24, 2026. – MANAURE QUINTERO
Difficult to distinguish them as separate earthquakes
Lucía Lozano indicated that, as they occur so closely together over time, it is sometimes difficult to distinguish one earthquake from another.
“In the records the waves are mixed. Unless the measuring equipment is very close and the difference in the signals is more visible,” he noted.
Not only for seismologists: also people who suffer from a seismic doublet may believe that it is a single tremor.
“The population feels very strong shakes, very close together, and one can think that it is the same earthquake.””he added.
The specialist indicated that the most significant thing about earthquakes of such a large magnitude “is that they do not really break a point, but rather they normally break an area.”
“They are not located at a specific point, but rather they break along a fault. For these magnitudes we can be talking about lengths of 150 km of rupture, for about 20 or 40 km wide. It is a very large area,” he pointed out.
Victim Estimation
The USGS has estimated between 10,000 and 100,000 possible deaths from this episode, a wide range that the seismologist explained.
“Apart from the magnitudes, they have to have information on the intensities, on ground movement prediction equations, on how the zones of the geology of the area propagate. Also on the population, on the vulnerability of buildings and constructions. It is a combination of many data and not all of them are known exactly, which is why the ranges of variability are so wide,” he said.
Regarding possible aftershocks, he stated that “with earthquakes of these magnitudes, it is expected that seismicity will continue in the coming days, weeks and months, even over the course of a year.”
“But the usual thing is that the number of earthquakes decreases over time, although high magnitude aftershocks cannot be ruled out”he added.
The affected area of the Caribbean “has significant seismic activity, without being one of the highest rates.”
Wednesday’s earthquakes “have occurred in an area bordering the Caribbean plate with the South American plate.” The area “has systems of large strike-slip faults and it is expected that major earthquakes will occur in them.”