The earthquake struck the Marmara Sea, with its largest aftershock registering 5.9 magnitude. Felt as far away as İzmir, Ankara, and Çanakkale, the shaking sent frightened Istanbul residents into the streets. Officials reported 151 injuries, primarily due to panic-induced jumps from heights. While a derelict building collapsed in Fatih, active structures were held mainly. Authorities closed all educational institutions for two days and granted leave to vulnerable public employees.
Analyzing the quake for T24, Prof. Dr. Ercan identified it as a main shock on the Trakya branch of the North Anatolian Fault, not a precursor to the imminent 'Big One' (expected M7.0-7.2 from the Silivri area). He stated the event provided crucial data, suggesting the major quake could last over 30 seconds, but stressed it doesn't change the overall probability or timeline. He predicted aftershocks up to M5.5 could persist for about two weeks.
Prof. Dr. Hasan Sözbilir, Director of DEU's Earthquake Research Center, offered a nuanced perspective, also speaking to T24. He suggested that since the M6.2 quake ruptured only a short fault segment (approx. 10km), it might slightly decrease the likelihood of an immediate >M7.0 event on that specific piece by relieving some stress. He viewed the quake as a 'test' for Istanbul, noting that progress in urban renewal likely prevented worse outcomes. However, he warned of potential 'earthquake storms' if stress shifts to adjacent fault fragments. Prof. Dr. Naci Görür stated on social media that such earthquakes increase stress on the fault system, highlighting the ongoing need for preparedness beyond simply reacting to tremors.
Compounding the seismic threat and speaking to Flash Haber TV, Geophysics Specialist Hurşit Canlı highlighted the critical risk of unstable ground. Drawing parallels with the catastrophic destruction in Hatay during the 2023 earthquakes – a city built on soft alluvial soil far from the epicenter – Canlı warned against building on such foundations, comparing it to constructing on 'cotton.' He referenced prior geotechnical studies in Istanbul areas like Esenyurt, revealing 'hidden landslide' potential or 'slip zones' beneath the surface. "In a serious earthquake... this block will slide downwards," Canlı cautioned, explaining how prolonged shaking can trigger movement in these unstable subterranean layers, especially on slopes or near the sea.
The consensus among experts is clear: Wednesday's quake, while not the long-feared catastrophe, serves as a potent reminder. Comprehensive preparedness for Istanbul must urgently address building reinforcement and urban transformation – which Prof. Ercan noted has been slow and costly – and the fundamental risks posed by the very ground the city stands upon. Rigorous geological assessment and informed construction practices are paramount.