Experts explain cause of Venezuela's two consecutive earthquakes

Two powerful earthquakes that struck Venezuela within a minute of each other on June 24 were caused by movements along two interconnected fault systems at the boundary between the Caribbean and South American tectonic plates, according to experts.

According to the US Geological Survey, a magnitude-7.1 earthquake struck near Montalbán, Venezuela, on June 24, followed less than a minute later by a magnitude-7.5 quake. The magnitude of the first earthquake was later revised to 7.2.

Qu Guosheng, former chief engineer of the China Earthquake Emergency Search and Rescue Center, told China News Service that the first magnitude-7.2 earthquake occurred along the Central Range Fault, a thrust strike-slip fault at the eastern end of the Andes Mountains. The rupture propagated northeastward and subsequently triggered movement along the Boconó-San Sebastián-El Pilar fault system, an east-west trending strike-slip fault zone, resulting in the second earthquake.

Sergio Barrientos, director of the National Seismological Center at the University of Chile, said Caracas and surrounding areas have experienced several major earthquakes throughout history because the region lies along the boundary between the Caribbean and South American plates.

Barrientos noted that major earthquakes struck Caracas in 1812, 1900 and 1967. The relative movement of the Caribbean Plate against the South American Plate, which shifts by about two centimeters each year, gradually builds up stress in the Earth's crust. When the accumulated stress exceeds the strength of the rocks, the crust ruptures along the plate boundary, triggering earthquakes. He said the two recent earthquakes were caused by the same tectonic process.

Barrientos added that both earthquakes were shallow and occurred along near-vertical faults, allowing the movement between the tectonic plates to release substantial energy, contributing to significant casualties and property damage.

The two earthquakes, both exceeding magnitude 7, have raised concerns about whether the Earth is entering a period of heightened seismic activity. However, Barrientos said global statistics suggest earthquakes of this scale fall within the normal range of tectonic activity.

On average, one magnitude 8 or stronger earthquake occurs worldwide each year, he said. Statistically, each magnitude 8 earthquake is accompanied by about 10 magnitude 7 earthquakes, 100 magnitude 6 earthquakes and 1,000 magnitude 5 earthquakes over the same period. Barrientos said earthquakes of the size recorded in Venezuela are a normal geological phenomenon, particularly within the seismically active Pacific Ring of Fire and other tectonically active regions.