Luca Del Zilio, a researcher at TH Zurich, provides an excellent assessment of the recent earthquakes in Turkey and Syria, giving light on the event’s complexity. He analyzes the lessons that may be gained from it in order to better comprehend and prepare for future earthquakes in the region.

Experts confirm that a twin earthquake struck Turkey and Syria.

The first earthquake tipped the scales, causing the second severe earthquake on a neighboring fault to occur very shortly thereafter.
Given the lack of a strong earthquake along the North Anatolian Fault south of Istanbul and beneath the Sea of Marmara for the past 250 years, experts assume the existence of a “seismic gap.”

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Very high earthquake danger and risk exist in the Turkish metropolitan area.

You and your colleague Jean-Paul Ampuero from Geoazur have just published a commentary in a scholarly publication on the early February earthquakes in Turkey. What’s fresh?

The two massive earthquakes that struck Turkey and Syria on February 6, 2023, were of comparable magnitude (7.8 and 7.6) and occurred within nine hours of one another. These events are referred to as an earthquake doublet because they consist of a pair of severe earthquakes with centroids that are closer than their rupture size and that occur within a shorter time frame than the recurrence period predicted from plate motion.

Long rumors circulated of an extraordinarily powerful aftershock.

In this instance, the second earthquake was not a conventional aftershock, as it was nearly as powerful as the initial quake and occurred on a separate adjacent fault. According to Bath’s Law, the biggest aftershock is typically around 1.2 magnitudes less than the primary earthquake. A sequence of earthquakes, such as the recent occurrences in Turkey and Syria, has distinct characteristics. This research increases our understanding of earthquakes and our capacity to anticipate them.

Why did a double earthquake occur?

The first earthquake likely contributed to a rise in static tension in the region where the second earthquake occurred. This rise may not have been significant, but it may have been enough to trigger the second incident mere hours later. This indicates that both flaws were under severe stress. The initial quake may have provided the last push to the second fault zone, which had accumulated decades of stress and was already dangerously loaded. Further studies will aid in our comprehension of this component of earthquake interaction.

What lessons may be drawn from your findings for the reconstruction of damaged towns and villages?

It is impossible to escape significant damage from earthquakes of this size, especially when cities are built directly on seismically active fault lines, resulting in massive surface displacements of six to eight meters.

This occurrence highlights the need to better comprehend the significant ground motion near a fault and to update risk management procedures, such as by assessing how stress transfer has altered the region’s hazard likelihood. Ideally, we should also determine the extent to which powerful mainshocks have altered the structural integrity of structures and increased their susceptibility to aftershocks.

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Were we not long aware of the region’s high seismic danger and the attendant tremendous risk?

In recent years, several European institutes, such as ETH Zurich and the Swiss Seismological Service, have devoted a great deal of work to assessing the earthquake risk across Europe. We now have an accessible external pagemap showing Europecall made’s seismic hazard thanks to their efforts.

This image demonstrates that the North Anatolian Fault and the East Anatolian Fault, which both run through Turkey, are two of the most active fault systems in Europe and the globe, posing a significant seismic risk to the region. Istanbul is situated on the North Anatolian Fault, which poses a severe threat. Many earthquakes have occurred along this fault in the recent century. There is currently a 250-year-old seismic void south of Istanbul and beneath the Sea of Marmara as a result of these occurrences.

Such zones are sometimes referred to by seismologists as seismic gaps because they are parts of a fault system where little or no seismic activity has occurred over an extended period of time, despite the fact that adjacent sections have been damaged by earthquakes. We hypothesize that these are regions along a fault where strains develop before unleashing a massive quantity of energy all at once, resulting in strong earthquakes.

What is the outlook for the future, and what will occur next?

In summary, the present emphasis is on addressing the catastrophic loss of life and property. Many follow-up studies to our research will give more insight into this terrible incident in the next months and years.

We intend to learn from this in order to make buildings safer and to be better prepared for similar disasters. As scientists, we hope that this occurrence will shed light on the physics and mechanics of faults and earthquakes.