On February 6, 2023, a pair of powerful earthquakes rocked Turkey and Syria, leaving a trail of devastation in their wake. The latest reported death toll stands at a staggering 50,000, with over a lakh of others injured across 11 different provinces. The impact of these earthquakes was widespread, affecting approximately 1.5 crore people and 40 lakh buildings. Shockingly, around 3.45 lakh apartments were destroyed in the catastrophe. While Turkey has a history of seismic activity, the scale of these earthquakes took scientists by surprise.
A study published in the journal Science on August 3 shed light on the complex interplay of tectonic forces that resulted in this disaster. The research not only deepened our understanding of these earthquakes and their unprecedented power but also provided insights into how scientists can forecast similar events in the future.
To comprehend these earthquakes, scientists must first understand how they occur and grow in intensity. The Earth’s crust is composed of tectonic plates, and earthquakes happen at the points where these plates interact. They can collide, pull apart, or slide past each other. When these plates abruptly grind and slip, they release enormous amounts of pent-up pressure, generating earthquakes.
In the case of Turkey, the earthquakes were primarily concentrated along the East and North Anatolian Fault Lines, which are roughly 700 km and 1,500 km long, respectively. Remarkably, the study revealed that these geological behemoths engaged in a constant dialogue. Zhe Jia, the lead author of the study and a postdoc at the University of San Diego, California, likened this communication between fault lines to a conversation conducted through stress interactions.
However, during the earthquakes, this “conversation” was disrupted by what can be described as shouting. A seismic “cascade” broke through fault bends and step-overs, which are typically barriers to the propagation of an earthquake. Fault bends and step-overs are akin to curves and gaps in a road. In terms of earthquakes, they refer to areas where fault lines change direction or have small gaps. These factors play a crucial role in influencing the occurrence and intensity of earthquakes. Dr. Jia emphasized that while these known fault lines played a significant role, the sheer magnitude of the quakes exceeded all expectations.
The disruptive interaction of fault lines triggered a cascade of ruptures, resulting in a total rupture length that was larger than usual and a higher potential for widespread destruction. This was exemplified by the presence of craters observed by scientists in areas where no buildings or casualties were reported. Dr. Jia, who has extensively studied earthquakes, admitted to being surprised by the “dialogue” between the fault lines. Other experts in the field, such as seismologists Sylvain Barbot from the University of Southern California, Los Angeles, and Sezim Guvercin from Istanbul’s Kandilli Observatory, echoed similar sentiments.
In analyzing these earthquakes, researchers faced a race against time to gather and analyze data, allowing them to piece together the sequence of events and their evolution. This information plays a crucial role in understanding the associated hazards. Dr. Jia and his team received satellite data just nine hours after the earthquakes occurred. They compared this data with historical records, GPS data, and images of the Earth before and after the events. Additionally, they utilized supercomputers to simulate the earthquakes based on available data, enabling them to gain valuable insights.
The study published in Science stood out due to the two methods employed: kinematic slip inversion and fault-property modeling. Kinematic slip inversion involves rewinding an earthquake video to understand how fault surfaces moved, aiding in understanding the underground events that took place. Fault-property modeling, on the other hand, entails estimating the characteristics of the fault, such as friction and material properties, to predict the spread of an earthquake along it. These predictions are then compared to real earthquake data to gain further insights. Dr. Jia compared the process to spotting differences between two identical pictures.
This detailed analysis not only provides researchers with a view of the surface but also deeper insights into the deformation of the Earth’s surface and the shape and slip of faults. Dr. Barbot, who conducted separate studies on the Turkey-Syria earthquakes, emphasized the importance of measuring the Earth’s deformation in understanding these events.
The field of earthquake science extends beyond the laboratory and has significant implications for policy and disaster management. The lessons learned from Turkey’s devastating earthquakes have far-reaching effects, highlighting the enigmatic nature of these seismic events. It is worth mentioning that Turkey was aware of the possibility of such an earthquake, leading to the implementation of building codes designed to prevent such disasters. However, these policies have not been enforced uniformly across the country for various reasons. Dr. Barbot lamented that this gamble had severe consequences.
As news of people trapped under rubble and collapsed buildings spread, shockwaves reverberated throughout Turkey. Dr. Guvercin and her team worked tirelessly to gather information about those affected by the disaster. She expressed frustration at the corrupt system that contributed to the severity of the catastrophe. Reflecting on the study, she stated that it would remain a painful memory for her.
In conclusion, the earthquakes that struck Turkey and Syria in February 2023 were characterized by their unprecedented scale of destruction. Scientific research has helped shed light on the complex interplay of tectonic forces that led to these earthquakes, furthering our understanding of their power and potential forecasting methods. The implications of this study extend beyond the confines of the scientific community, reminding us of the unpredictable nature of seismic events and the importance of robust policies and disaster management.
