Two major earthquakes struck north-central Venezuela on June 24, occurring just 39 seconds apart and measuring 7.2 and 7.5 in magnitude. Government officials stated that thousands of people were killed and thousands more injured in the twin quakes, which struck near San Felipe and Yumare respectively and formed a rare seismic sequence known as an “earthquake doublet.”

The first earthquake, measuring 7.2, struck near San Felipe, while the second, stronger 7.5-magnitude quake struck near Yumare. The two events had slightly different epicenters, a detail that researchers say supports the classification of the sequence as an earthquake doublet—one in which two large, closely timed quakes rupture adjacent or interacting fault segments. Typically, large earthquakes are followed by smaller aftershocks, but in this case, the second quake was even more powerful than the first.

Researchers believe the earthquake doublet could provide insight into how large fault systems interact and how some destructive earthquakes grow. Intense seismic events can alter stress on nearby faults or along the same fault, and such altered stress can trigger another major earthquake. While sequences of multiple major earthquakes are infrequent, they are not unprecedented; similar events occurred in Kahramanmaraş, Turkey, in 2023, and in Harnai, Pakistan, in 1997.

Seismologists are reaching a consensus that treating faults as isolated structures may underestimate the destructive power of earthquakes in regions where multiple tectonic faults meet. Multiple tectonic faults converge in Venezuela, including the Boconó, Morón, San Sebastián, and El Pilar faults. This system lies along the boundary between the South American and Caribbean plates and shares key characteristics with California’s San Andreas Fault, which runs along the boundary between the Pacific and North American plates. Both systems are right-lateral strike-slip fault systems, where crustal blocks slide horizontally past each other.

However, the Venezuelan plate boundary has a more complex fault architecture than California’s, according to Julián García Mayordomo, a senior scientist in the Geological Hazards and Climate Change Department at the Geological and Mining Institute of Spain. “The main difference is that the Venezuelan plate boundary has a much more complex fault architecture,” García Mayordomo said. “The other difference is the speed at which the plates move.” The complexity stems largely from the Maracaibo block, whose interaction with surrounding faults creates a more intricate plate boundary than California’s.

In Venezuela, tectonic plates move past each other at about 0.8 inches (20 millimeters) per year, slower than the roughly 1.2 inches (30 millimeters) per year along the San Andreas Fault. Faster plate motion allows tectonic stress to accumulate more quickly and influences how often large earthquakes occur over long timescales, though it does not determine precisely when the next earthquake will strike. Estimated slip rates in Venezuela suggest recurrence intervals of one to two centuries for major earthquakes. The region experienced a devastating earthquake sequence in 1812 that included quakes of magnitude 7.5, 7.2, and 6.5. A 2018 study concluded that the Boconó Fault had accumulated enough strain to generate another major earthquake.

Geologist and geophysicist Liliane Burkhard of the University of Bern emphasized the scientific value of the Venezuela doublet. “Interactions between neighboring faults can play an important role in the evolution of large earthquakes,” she said. Burkhard, who is the first author of a recent study suggesting that the junction between the San Andreas and San Jacinto faults in Southern California is experiencing some of its highest tectonic stress levels in the past 1,000 years, noted that the Venezuela doublet provides real-time data captured by seismic instruments showing how different faults interact during earthquakes. “It is the kind of natural event that can sharpen and test the rupture-interaction concepts that paleoseismic models like ours can only infer indirectly,” Burkhard said. She added, “Our Cajon Pass work relied on centuries of paleoseismic reconstructions to infer how stress evolves and whether ruptures can cross between fault systems.”

Many seismic hazard models in California do not account for multi-fault interactions, despite the convergence of multiple tectonic faults around the San Andreas system. Along the San Andreas Fault, magnitude 7 or larger earthquakes occur on average every 100 to 200 years, though the frequency of recurrence varies by segment. The last major rupture in Southern California was the magnitude 7.9 Fort Tejon earthquake in 1857. Recurrence of large earthquakes is highly irregular and depends on many factors beyond plate speed, including fault geometry, historical strain accumulation, and interactions with neighboring fault systems.

Why It Matters

The June 24 earthquake doublet in Venezuela underscores the limitations of traditional seismic hazard models that treat faults in isolation. With thousands dead and injured, the event has immediate humanitarian consequences, but it also offers rare scientific data that could improve earthquake forecasting in tectonically complex regions like Venezuela and California. The real-time observations from this doublet may lead to updated risk assessments in areas where multiple faults intersect, potentially influencing building codes, emergency planning, and infrastructure resilience.

The historical precedent of the 1812 Venezuela quakes and the recent identification of accumulated strain on the Boconó Fault suggest that such events, while irregular, are part of the region’s seismic reality. As researchers analyze how stress transferred between faults during the doublet, the findings could refine global understanding of how major earthquakes initiate, propagate, and sometimes trigger subsequent large ruptures—a critical advancement for earthquake-prone regions worldwide.