Why Venezuela’s earthquakes were so devastating: Geology, vulnerability, and years of structural neglect

The destruction caused by Venezuela’s recent earthquakes (considered the nation’s most destructive and deadly since 1900) cannot be explained by magnitude alone. It also resulted from the interaction of geological conditions, structural vulnerabilities, and a prolonged social and economic crisis that has weakened the country’s ability to prepare for and withstand natural hazards. From the characteristics of the earthquakes themselves to decades of inadequate urban development and institutional decline, several factors combined to amplify the disaster.
The death toll currently stands at 4,336 deceased, 16,740 wounded and 19,000 displaced. At least 20,000 remain disappeared.
Two earthquakes, one amplified impact
One of the most important aspects of the event was that residents experienced two significant earthquakes in close succession. The twin earthquakes were a rare phenomenon known as a seismic doublet — magnitude 7.2 and 7.5, striking just 39 seconds apart, with epicenters only kilometers apart.
The San Sebastián fault forms part of the diffuse boundary between the Caribbean and South American tectonic plates, linking the Boconó Fault to the west and the El Pilar Fault System to the east. Since it lies between the other two systems, the intense telluric movement spread across the faults, affecting many states. The area is known to experience earthquakes like this roughly once a century: the plates’ horizontal interaction presses them against each other, building up energy over time until it’s suddenly released.
At a depth of 20.3 km for the first and only 12 km for the second, they were shallow-focused earthquakes — almost as surface-level as earthquakes can be. It is most likely that the first earthquake, which started on the Boconó Fault in the Los Andes area, triggered the second one on the San Sebastián Fault. The tremors were detected in Brazil, Colombia, and the Caribbean.
Why La Guaira and Caracas are especially vulnerable
Since nearly all of the country’s fault activity is concentrated along its northern coast, Caracas and La Guaira sit at the epicenter of Venezuela’s seismic risk. The same region that holds 80 percent of the population also marks the boundary between the Caribbean and South American tectonic plates.
La Guaira’s coastline sits right across from the San Sebastián Fault, where the two plates grind slowly past each other in opposite directions, running just offshore, roughly parallel to the coast. The rupture from the seismic doublet occurred close to this coastal edge — and where the rupture is largest, seismic waves arrive stronger and with greater amplitude, regardless of where the epicenter technically sits.
But the deeper vulnerability lies underground. Cities built on soft, sedimentary soil experience far more intense shaking than those on solid bedrock, because these looser soils amplify seismic waves rather than absorbing them.
Much of La Guaira itself rests on fluvial cones. These shallow layers of loose sediment, deposited by rivers over time, acted like a filter that dramatically intensified ground motion. Compounding this, many local soils have been only partially consolidated; further weakened by prior major landslides, this left them with moderate structural resistance.
Whether this amplification becomes catastrophic depends on resonance: if the frequencies amplified by the sediment match a nearby building’s natural oscillation, the shaking is magnified even further.
After the 1999 Vargas Tragedy, Japanese and Venezuelan researchers conducted geological surveys and seismic investigations, and created hazard maps to identify the most vulnerable areas along the northern coast. La Guaira was highlighted as a high-risk area in several of the severely impacted zones in the 2026 earthquakes. A later study, the Caracas Seismic Microzoning Project (2005-2009), analyzed soil conditions, seismic activity, and expected earthquake impacts across the capital, identifying areas at greater seismic risk and offering recommendations for disaster preparedness and urban planning. Experts in Mexico had detected unusual seismic activity in the area since May.
A disaster made worse by social conditions
The earthquake also struck a country facing a prolonged humanitarian emergency. Since 2014, Venezuela has experienced one of the deepest economic and social crises in Latin America’s modern history, with widespread shortages, the mass migration of nine million people, declining public services, and a dramatic reduction in state capacity.
Amidst this long-standing humanitarian emergency, Venezuela’s public health system faced the disaster with serious deficiencies. Due to migration, many hospitals have struggled for years with shortages of medicines, equipment, reliable electricity, running water, and specialized personnel. Such weaknesses complicate emergency response precisely when rapid trauma care and coordinated medical services are most needed.
Economic collapse has also reduced the capacity of households, businesses, and governments to maintain the built environment. A deeply contracted economy with limited access to stable employment pushed a large share of workers into the informal sector, reducing incomes available for property maintenance and renovations.
As a result, many residential and commercial buildings have gone years without adequate inspection, repair, or seismic retrofitting. Deferred maintenance may not be noticeable under normal conditions, but earthquakes expose these hidden vulnerabilities. Aging concrete, corrosion of reinforcing steel, deteriorating foundations, and neglected structural elements all increase the probability of severe damage during strong ground-shaking.
Years of underinvestment have also weakened Venezuela's capacity to prepare for and respond to earthquakes. Institutions such as FUNVISIS (Fundación Venezolana de Investigaciones Sismológicas), responsible for monitoring seismic activity, conducting hazard research, maintaining seismic networks, and promoting preparedness and public education, have faced persistent budgetary and operational constraints that experts say have limited their capabilities before, during and after the disaster. Similar challenges have affected civil protection and municipal fire departments, many of which have shortages of personnel, equipment, vehicles, communications systems, and emergency supplies.
Together, these reductions in scientific monitoring, disaster preparedness, and emergency response capacity have diminished the country’s ability to anticipate seismic risks, educate vulnerable communities, and respond effectively when major earthquakes occur. In this sense, the earthquakes became not only a natural disaster but also a reflection of years of declining institutional and economic resilience.
Corruption and unsafe housing in La Guaira
The tragedy also raises questions about the quality of some social housing developments in La Guaira, constructed since Hugo Chávez Frías’ presidency.
Investigations by Armando.info have documented allegations of corruption, cost overruns, poor construction practices, and weak oversight in certain public housing projects developed over the past two decades. These investigations describe projects where, despite substantial public investment, construction quality and engineering standards may have been compromised:
Such concerns are particularly significant in La Guaira because engineering solutions must account for difficult ground conditions, including unstable slopes and soft sediments. Buildings designed without sufficiently considering these geological constraints — or constructed below their intended specifications — can face substantially greater risks during earthquakes.
While each damaged building requires individual forensic investigation before assigning responsibility, the broader lesson is clear: seismic safety depends not only on engineering design but also on rigorous construction standards, effective inspections, and transparent public oversight.
The devastation illustrates that earthquakes become disasters through the interaction of natural hazards and human vulnerability. Understanding these interconnected causes is essential not only for explaining the scale of the destruction, but also for reducing the impacts of future earthquakes through better planning, stronger institutions, and more resilient construction.