Venezuela earthquakes: Science weighs in on 30-year cycle theory

The idea that earthquakes in Venezuela follow a predictable 30-year cycle is a misconception, but historical analysis reveals unsettling temporal patterns. While seismicity does not adhere to a strict calendar, a deep dive into the country's seismic past suggests periods of heightened risk.

This analysis gains new relevance after a recent destructive earthquake struck northern Venezuela, devastating La Guaira. The event, a pair of magnitude 7.2 and 7.5 tremors just 39 seconds apart, has reignited concerns about seismic safety.

Pioneering Venezuelan seismologist Melchor Centeno Graü, a founding member of the Academy of Physical, Mathematical and Natural Sciences of Venezuela (Acfiman), analyzed seismic events between 1530 and 1949. His work, "Estudios sismológicos," published in 1940, proposed a "Law of dangerous seismic coincidences." Centeno Graü calculated that 82% of destructive earthquakes in the catalog occurred within intervals of 29, 30, 31, or 32 years.

Centeno Graü clarified that this pattern did not enable prediction but rather the identification of periods with a greater likelihood of seismic events. He calculated a potential destructive earthquake occurrence between 1968 and 1971, with the 1967 Caracas earthquake of magnitude 6.6 happening just five months prior to this window.

Despite these historical patterns, scientists universally agree that predicting earthquakes with exact dates, times, and magnitudes is currently impossible. However, long-term probabilities can be calculated based on historical event frequencies. Centeno Graü also advocated for studying areas most affected by past catastrophes to inform future construction and mitigate damage.