Source: French to English Tester Published on: 2026-07-02
Source: The Conversation – France in French (2)– By Sylvain Barbot, Professor of Earth Sciences, USC Dornsife College of Letters, Arts and Sciences
Venezuela and its capital, Caracas, have beenhit by two powerful seismic shocksOn June 24, 2026, just seconds apart. The two earthquakes, measuring 7.2 and 7.5 in magnitude, caused the collapse of buildings in several cities in the northern part of the country,causing more than 2,200 deathsand trapping many other people, according to the authorities.
The geophysicistSylvain Barbotexplains what is known at this stage about this double tremor and the remaining risks. A researcher at the University of Southern California, he also draws a parallel with the San Andreas fault in the United States.
Earthquakes are natural phenomena that generally occur at the boundaries ofEarth’s tectonic plates. These plates, which make up the Earth’s crust, have a thickness of several tens of kilometers and support both oceans and continents. They are in constant motion, but not in a fluid or regular manner.
Venezuela is located in theborder between two of these plates : the South American plate and the Caribbean plate. By sliding against each other, they can lock, accumulating stress until they suddenly give way, causing an earthquake.
U.S. Geological Survey
On June 24, 2026,two strong tremors seismicoccurred 39 seconds apart, both with a magnitude greater than 7. They could be two distinct earthquakes or a single earthquake with two rupture phases. Scientists do not know yet, as the data is still being analyzed.
The hypothesis of two distinct earthquakes is quite plausible. In 2023, Turkey experienced aseismic “doublet”, with two earthquakes of magnitude greater than 7 occurring eight hours apart. In this case, it was clearly two distinct events.
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In Venezuela, the two shocks were only a few seconds apart. In the past, ofvery long faults have undergone displacements on different segmentsduring earthquakes of this magnitude, giving the impression that they were two distinct earthquakes when in reality they corresponded totwo ruptures of the same seismic event.
What triggers such destructive earthquakes?
Earthquakes are determined by thethe way in which rocks resist shear and pressure stresses. These stresses can accumulate over years, even decades, until they exceed the strength of the rocks, which then end up breaking. From that moment on, the stress propagates and the fracture extends.
This is not a gradual movement. In a few seconds, the plates shift abruptly, causing an earthquake. This phenomenon occurs several kilometers below the surface, where the temperature and pressure are very high.
This phenomenon is difficult toreproduce in the laboratoryand involves numerous processes, pertaining as much to mechanics as to chemistry or fluid flow. Its result is, however, simple: a rupture occurs, during which rock masses slide against each other, creating a fracture that breaks everything in its path and causes significant damage.
Is Venezuela’s fault system comparable to the San Andreas Fault in California?
The faults involved in the earthquake in Venezuela and the San Andreas fault in California are very similar. They aretransform fault, where the plates slide horizontally relative to each other according to adetachment movement.
Even themovement speedsare quite close. In Venezuela, thetwo plates slide past each otherAt an average speed of about 20 millimeters per year. Along the San Andreas fault, this movement is slightly faster, on the order of 30 millimeters per year.
U.S. Geological Survey
These faults also produce high-magnitude earthquakes at comparable frequencies. On the San Andreas fault, scientists estimate that an earthquake of magnitude 7 or higher occurs on averageabout every 170 years, even ifthis interval varies according to the segments of the fault. However, this is not a clockwork mechanism: these earthquakes can occur much more frequently… or much more rarely.
The last “Big One” in Southern California dates back toFort Tejon earthquake, in 1857, a powerful earthquake with a magnitude of 7.9. A recent study suggests that theaccumulated stresses along the southern part of the San Andreas Faultare today more significant than at any other time in the past thousand years. If the hypotheses of this study are correct, the fault could be close to breaking. But the frequency of major earthquakes is very variable: the next one could occur in a hundred years… or tomorrow. No one can predict it.
These faults have already caused numerous earthquakes in the past. This alone is an argument in favor of strict earthquake-resistant standards for buildings and infrastructure, such as bridges or hospitals, as well as emergency preparedness plans.
Have scientists identified warning signs that could predict an imminent earthquake?
Scientists are actively seeking toidentify reliable precursorswhich would allow warning before a seismic rupture, but no sufficiently reliable signal has yet been identified.
There are anecdotal cases where swarms of small earthquakes preceded a major rupture and which, in hindsight, could have been early signs of a great earthquake to come. Butthis is not systematic.
Themachine learning has highlightedregular changes in microseismicity preceding major ruptures, and some studies on the physics of earthquakes havestarted to explainwhy this phenomenon occurs.
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There are therefore good reasons to hope that in the future, we will be able to connect these various clues and better understand the mechanisms at play. But we are not there yet.
On the other hand, it is possible to issue very short-term alerts. When an earthquake begins, it generates several types of seismic waves that propagate at different speeds. The fastest arrive first and can be detected,which allows scientists to predictthe arrival of the second and third wave trains, slower and generally more destructive.
After the first waves, called P waves, come the S waves, or shear waves, which are a bit more powerful. Then come the surface waves. The first P waves can trigger early warning systems, offering only a few seconds to react, but that is enough to halt traffic, shut off gas pipelines, stop high-speed trains, and secure infrastructures sensitive to shaking. It can also leave just enough time to take shelter and avoid being killed by the collapse of a building, whether at the office or at home.
What are the risks now for Venezuela?
Geologists are well acquainted with the tectonics of this region, as they have been mapping these faults and studying their behavior for decades. But to understand this event precisely, scientists must go to the field to assess the extent of the damage and measure the scope of the rupture.
Moreover, earthquakes cause other risks. After the tremors, the region remains for several months, even several years,more exposed to landslides, because the rocks were destabilized.
This means that the upcoming heavy rains are likely to trigger landslides. Venezuela must therefore expect new damage, other dangers, and, unfortunately, new loss of life.
Sylvain Barbot does not work for, advise, hold shares in, or receive funds from any organization that could benefit from this article, and has declared no affiliation other than his research institution.
–ref. What is known about the recent earthquakes in Venezuela, and the risks that remain –https://theconversation.com/what-is-known-about-the-recent-earthquakes-in-venezuela-and-the-risks-that-remain-286665