Source: AGU Advances
The 2023 Kahramanmaraş earthquake struck southern Türkiye and Syria along the East Anatolian Fault. The magnitude 7.8 quake and its magnitude 7.5 aftershock devastated the region, killing tens of thousands of people and destroying hundreds of thousands of buildings.
Before the earthquake, seismologists warned that the area was ripe for a major seismic event. The region sits at the junction of the Anatolian, Arabian, and Eurasian plates and is rife with faults. In the years since the quake, scientists have been researching the seismic links between the main shock and aftershocks that struck across hundreds of kilometers.
Luo et al. used interferometric synthetic aperture radar on imagery collected by the Sentinel-1 satellite and Advanced Land Observing Satellite-2 (ALOS-2) to measure changes in land surface elevation following the earthquake.
The analysis identified eight areas outside the main rupture zone that saw localized changes in surface elevation triggered by the 2023 earthquake sequence, none of which were associated with known, discrete seismic events.
Of these events, four were typical aseismic events. Aseismic events involve geologic movement without earthquakes. For instance, in a slow-slip event, energy is released along a fault line gradually, over the course of weeks or months, causing land to move in a way that is imperceptible without scientific instruments.
Two others were seismic events—in which energy along a fault line was released abruptly—that were masked by the main earthquake’s seismic waves.
The remaining two events stood out. Dubbed “silent” events, the quakes—both greater than magnitude 5—did not produce local aftershocks or radiate detectable seismic waves as a typical earthquake would. The amount of stress along the fault did drop significantly after the tremor, however, similar to how it would in a regular earthquake. The authors suggest the aseismic events with a high drop in stress represent a previously unidentified transitional mode between regular earthquakes and slow-slip events.
Though more reviews of recent earthquakes are needed to determine whether these silent events were outliers, the findings could represent a missing slip type in models, with significant implications for scientists’ understanding of earthquake physics. The results also reveal new insights into seismic hazards in the vicinity of large, deadly quakes. (AGU Advances, https://doi.org/10.1029/2024AV001457, 2025)
—Aaron Sidder, Science Writer
