The earthquake that devastated Turkey and Syria in February 2023 killed at least 59,259 people and caused economic damage estimated at more than $160 billion. The earthquake was surprisingly strong given the historical seismicity of the region, and the rupture it caused was larger than that of any major earthquake documented on the East Anatolian Fault in several hundred years. Now a recently published paper by earthquake researchers co-led by CEE associate professor Ahmed Elbanna, sheds light on the strength and devastation of the earthquake and gives insight into how to prepare better for future quakes.
“It is critical to understand the mechanics of this damaging earthquake, how it started, why it grew that big, and what implications we can expect for the ground shaking and potential damage to the built environment in the U.S. and worldwide,” Elbanna said. “There are multiple similarities between the tectonic setting in Southeast Turkey and California, and we expect the next big earthquake on the San Andreas fault to be of a comparable, or even a bit larger, magnitude than the earthquake in Turkey. There are also similar seismic vulnerabilities in the built environment in the seismically prone areas of the U.S. that could amplify the economic losses.”
In this paper, the researchers used data and physics-based models to answer some of the outstanding questions about the earthquake. The East Anatolian Fault is one of the best instrumented faults in the world with multiple seismic stations within a couple of kilometers close to the fault trace. This gave researchers an unprecedented opportunity to visualize the rupture propagation and apply principles from fracture mechanics to understand its characteristics.
“Surprisingly, we did find that the rupture in this earthquake started in a quite atypical way: It initiated on a previously unmapped fault, the Narli fault, and quickly transitioned to a supershear speed,” Elbanna said. “Usually earthquakes propagate slower than the shear wave speed in the rocks. However, occasionally they can exceed that speed. This is similar to an airplane exceeding the speed of sound in air and producing a sonic boom. So when an earthquake overruns the shear waves it produces, it becomes a supershear event, and it produces damaging Mach cones, similar to what an airplane will generate.”
The full paper, “Dynamics of episodic supershear in the 2023 M7.8 Kahramanmaraş/Pazarcik earthquake, revealed by near-field records and computational modeling,” was published December 5, 2023, in Nature- Communications Earth and Environment. CEE alumnus Mohamed Abdelmeguid (PhD 23), as well as CEE alumnus and current Ph.D. student Chunhui Zhao (MS 21) are co-first authors. Authors also include Professor Ares Rosakis (Caltech) a recipient of an UIUC Honorary doctorate (2023).
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