In recent days, a succession of earthquakes recorded in different parts of the world has once again put seismic activity under scrutiny. Indonesia, Spain, Colombia, Venezuela, and Argentina were some of the countries where movements of varying magnitudes were detected, which may create the perception that the planet is going through an exceptional period.
However, the temporal proximity between these phenomena does not necessarily imply that there is a connection between them or that the Earth is experiencing an extraordinary increase in earthquakes.
The United States Geological Survey (USGS), one of the main organizations dedicated to studying these phenomena, explains that periods with more or fewer movements are part of the normal fluctuations of seismic activity.
A large number of countries suffered deaths and total destruction
In fact, the agency locates approximately 20,000 earthquakes around the world each year, which represents an average of about 55 movements daily. Many are of low magnitude and go unnoticed by the population.
So, why does it seem that the whole world shakes at the same time at certain moments?
To understand the phenomenon, it is necessary to observe what happens beneath the Earth's surface. The outer layer of the planet is fragmented into large blocks known as tectonic plates, which are in constant motion.
When two plates interact, they can accumulate enormous amounts of energy. If the tension exceeds the resistance of the rocks, a sudden rupture occurs that releases that energy in the form of seismic waves. It is then that an earthquake occurs.
This process happens continuously in different regions of the planet and explains why significant movements can be recorded in places separated by thousands of kilometers over a relatively short period.
For that reason, having an earthquake in Indonesia and shortly after detecting movements in South America or Europe is not enough to establish that the phenomena are related.
There are situations in which a large earthquake can modify the conditions of other faults. Specialists study, for example, a phenomenon known as dynamical triggering or activation, whereby the waves generated by a large quake can promote movements in distant locations under certain conditions.
However, this is a specific process that must be analyzed in each case. It does not mean that a strong earthquake automatically triggers a chain reaction of large quakes around the planet.
Are there more earthquakes than before?
The USGS response is clear: a temporary increase in the number of earthquakes does not mean that global seismic activity is growing abnormally.
Historical records allow for putting the figures into perspective. According to the U.S. agency, since approximately 1900, an average of 16 major earthquakes per year is expected: about 15 of magnitude 7 and one of magnitude 8 or higher.
This number is not identical every year. In some periods, the average is significantly exceeded, while in others the opposite occurs. In 2010, for example, 23 earthquakes of magnitude 7 or higher were recorded, while in 1989 there were only six.
There is another factor that contributes to the perception that more earthquakes are currently occurring: the ability to detect them has improved considerably.
The expansion of monitoring networks and the incorporation of more sensitive instruments allow for identifying movements that previously might have gone unrecorded. This is compounded by the speed of information circulation: an earthquake occurring thousands of kilometers away can become international news just minutes later.
Therefore, a greater number of earthquakes recorded in catalogs does not necessarily mean that more are occurring, but rather that there are currently better tools to detect them.
