MOSCOW, March 23, Zakhar Andreev. A month and a half after the tragedy in Turkey and Syria, strong tremors led to destruction in Pakistan and Ecuador. The casualties number in the hundreds. Why earthquakes follow one after another in different parts of the world and is it true that they have become more frequent in recent times?An earthquake of magnitude 6.5 occurred on Tuesday, March 21, in Afghanistan, near the border with Tajikistan. The aftershocks were felt in several countries, but Pakistan was the main blow. As of March 22, nine people died in the country, another 44 were injured.
On Saturday, March 18, an earthquake of magnitude 6.8 was recorded in the west of Ecuador. The epicenter was located 60 kilometers from the city of Guyakil. At least 14 people died, about 500 were injured. Dozens of buildings have been destroyed, hundreds have been damaged, and the debris removal continues.
According to local media, the vibrations of the earth's surface led to the liquefaction of the soil, which began to behave not like a solid, but like a dense liquid, or fluid. A similar phenomenon was noted earlier, including during the 2016 Ecuadorian earthquake (magnitude 7.8). type=»photo» data-crop-ratio=»0.666666666666667″ data-crop-width=»600″ data-crop-height=»400″ data-source-sid=»ap_photo» class=»lazyload» width=»1920 «height=»1280″ decoding=»async» />
Recall: on February 6, there were powerful tremors with an epicenter in Turkey. There, as well as in neighboring Syria, about 60 thousand people died due to large-scale destruction.
Since then, reports of earthquakes have become more frequent. Over the weekend, various regions of the planet were shaking, in particular the Magadan region (5.1), Alaska (5.4) and the Turkish province of Kahramanmarash (4.3), which suffered as a result of the February cataclysm.
Why it shakes more often
Specialists explain that seismic processes can really become more active temporarily, but this is a normal phenomenon.
According to Petr Shebalin, director of the Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Russian Academy of Sciences, there is a hypothesis about seismic cycles with a frequency of about 50 years. So, a series of powerful tremors was recorded in the period from 2004 to 2011. And before that, several earthquakes at once, including those with a magnitude greater than nine, occurred in the 50s of the twentieth century.
“It is not yet clear whether there is a pattern here or it is just a coincidence,” the scientist notes. “The strongest earthquakes (magnitude above six. – Ed.) have been recorded for more than a hundred years. Nevertheless, this is not such a long time to talk about which cycles. And early statistics are not available all over the globe.»
What caused this periodicity is unclear. Some scientists are trying to explain the intensification of earthquakes by tidal phenomena — when other celestial bodies act on the earth's crust. However, there is no convincing evidence for this.
Speaking of the event in Ecuador, Shebalin points out that this is a rather strong earthquake, but it cannot be called something unusual. The Latin American country is located in the zone of the so-called Pacific Ring of Fire, the most seismically active region of the planet.
The geophysicist emphasizes that the tremors in Ecuador have nothing to do with the disaster in Turkey and Syria.
Fifty a day
The USGS admits that in more and more earthquakes get statistics. But not because their number is really growing. The reason is the increase in the technical capabilities of science, in particular, the increase in the number of seismic instruments.
In addition, «as a result of the development of communications and increased interest in natural disasters, the public today is learning about earthquakes faster than ever before,» the organization's website says.
According to the US agency, which has the most advanced network of seismic sensors in In the world, over the past year (from March 21, 2022 to March 20, 2023) there were 16 earthquakes with a magnitude greater than seven, five of them were greater than 7.5. Turkish tremors are the most powerful (7.8).
At the same time, 13 events with a magnitude greater than seven were recorded over the previous similar period. Four of them exceeded 7.5, and two — one in the Alaska region, the other near the South Sandwich Islands — exceeded eight.
This roughly corresponds to the expectations of seismologists: on average, 15 earthquakes with a magnitude of seven and one with a magnitude of eight.
Since the beginning of the 21st century, the number of strong earthquakes has not only not increased, but has slightly decreased. Over the past ten years, 140 earthquakes of magnitude greater than seven have been recorded, and for the period 2003-2013 — 162.
The most extreme events also occur less frequently. Since 2013, there have been nine earthquakes with a magnitude greater than eight, in the previous similar period — 16.
In total, more than 20 thousand earthquakes occur every year — that is, about 55 per day. If these geological processes do not lead to human casualties, the mass media, as a rule, do not pay attention to them.