Earthquakes in the Caribbean More Likely at Night, Study Finds

A scientific study released by the National Seismological Research Center (CENAIS) on their website this Monday reveals that earthquakes are more likely to occur at night in specific Caribbean regions. This discovery coincides with the 6.1 magnitude earthquake that struck eastern Cuba early Monday, December 23, sparking public concern and emphasizing the need to understand the elements contributing to these events.

According to CENAIS, while it has traditionally been believed that earthquakes occur randomly and are not tied to climatic or time-of-day factors, data gathered between 1970 and 2019 from various Caribbean areas, including eastern Cuba, Puerto Rico, and parts of Colombia, show a distinct time-of-day distribution. The statistics indicate a higher frequency of seismic activities during nighttime hours, regardless of their magnitude.

Geophysical Factors at Play

Researchers have ruled out common explanations like "cultural noise" (less human and vehicular activity at night) or the influence of controlled explosions, as the pattern persists even in moderate quakes (greater than 3.0) that are detectable under any conditions. The study suggests that this nocturnal preference might be linked to disturbances in the Earth's magnetic field.

Electrical currents induced by these disturbances, such as those generated by solar winds in the ionosphere, appear to act as "triggers" for earthquakes in areas with high concentrations of piezoelectric minerals like quartz. These currents don’t directly cause earthquakes but might advance their timing, similar to how a shake accelerates the fall of a ripe fruit from a tree.

Beyond the Caribbean

The report also notes that this pattern is not limited to the Caribbean but is observed throughout the intertropical region, between 23.4 degrees north and south latitude. In these regions, the orientation and variation of the geomagnetic flow seem to play a crucial role in the hourly modulation of seismic activity.

While the study provides a potential explanation for this phenomenon based on the interaction between the geomagnetic field and the piezoelectric properties of rocks in the Earth's crust, the authors stress the importance of further research to fully understand the mechanisms involved. Such studies are essential in contexts like the Caribbean, where seismic activity is a constant threat, and findings could improve prediction models and natural disaster preparedness.

Importance of Continued Research

The 6.1 magnitude earthquake recorded early Monday, December 23, highlights the significance of these investigations and the need for early warning systems to mitigate the impact of such events on the population. As a result of this earthquake, landslides and the fall of large rocks were reported in Babujal, in the Guamá municipality, Santiago de Cuba. This quake occurred less than two months after two strong tremors of magnitudes 6.0 and 6.7 on November 10 south of Pilón, Granma.

According to the National Seismological Service, over 8,000 aftershocks have been recorded since then, with 137 being noticeable. CENAIS urges the public to stay informed through official channels.