At 04.17 am local time (02.17 CET) on Monday 6 February 2023, the first of two extremely large earthquakes struck south eastern Turkey, near the Syrian border. This first earthquake, which has been recorded as a 7.8Mw event, was followed at 15.24 local time (11.24 CET) by a second earthquake recorded as being a 7.5Mw event. At the time of writing, tens of thousands of people have lost their lives, and many more are injured, with damage to buildings and infrastructure widespread across the region. Aftershocks have continued in the days since, but an event of this scale and severity is unprecedented in a region known to be vulnerable to large seismic events.

“What we have seen is really exceptional. I do not remember any such large magnitude earthquakes occurring so close together in time.” said Professor Eser Çakti from the Department of Earthquake Engineering at Kandilli Observatory and Earthquake Research Institute, Boğaziçi University, Istanbul.

Professor Ziyadin Çaktir, Head of the Department of Geology at Istanbul Technical University explained “The first earthquake occurred between the cities of Kahramanmaraş and Gaziantep at 4:17 a.m. and triggered the second earthquake on a separate fault that branches off from the East Anatolian Fault to the north. The already damaged buildings were unable to withstand the second quake and collapsed, increasing the number of casualties and causing widespread destruction across a large area that includes 10 large cities and numerous towns.”

EGU’s Seismology Division President, Philippe Jousset continues “Turkey and Syria are located on a series of active faults, such as the North and East Anatolian Faults, marking the limit between several tectonic plates, including the Anatolian plate, which is sliding westwards along the Eurasian plate, but also from the south due to the northern movement of the Arabian plate. The two earthquakes on Monday occurred on different branches of the East Anatolian fault system.”

Both earthquakes occurred at a relatively shallow depth, the first at a depth of approximately 18km, the second at a depth of approximately 10km, and together ruptured a very large section of the Eastern Anatolian Fault, currently assessed to be between 400-500km. Although data is still being collected, the displacement along the fault line may be over 7m in places. There is also a risk of other associated hazards occurring as a result of the earthquakes and the aftershocks. “Strike-slip earthquakes are considered low risk for tsunami generation, however they may have a cascading effect generating tsunamigenic landslides and other complex hazards” said EGU’s Natural Hazards Division President Ira Didenkulova.

Following the event many people have been questioning why the impacts of these earthquakes have been so deadly. Professor Çakti gave her insight, “The recorded ground motion levels are severe and extend over a large area, particularly, and as expected, along the activated segments. Furthermore, there are basins developed as a result of regional tectonics. In the Antakya basin amplification and modification of strong ground motion are clear; the structural damage and loss of life are unprecedented. Antakya is also an important town historically and culturally. Many historical structures and artefacts might have been lost forever. ” She continued, “Many new buildings received beyond moderate damage, with a significant amount in a state of heavy damage or collapse. The current events demonstrate that though the structures designed and built post 1999 Kocaeli (İzmit) earthquake were assumed to be safer and less risky, the quality of structural design and construction still need to be improved in Turkey.”

Rescue and recovery operations have been underway since the event, but as time passes from the initial event many people are looking at how to prepare for the future. A member of EGU’s Biodiversity Task Force, PhD candidate and journalist Bikem Ekberzade says “We have been living in a state of polycrisis for several decades now, both man-made and nature-based. A double earthquake affecting several cities almost simultaneously may be a unique case study for the text books, but nevertheless, the fatal lag in response time and the humanitarian crises that unfolded with every hour of delay is proof that we are still stuck at the initial steps of our learning curve. Unless we address the problems that the current rate of urban expansion brings ahead of time, the destruction caused when these disasters strike will inevitably increase. And if we fail to learn from past mistakes, we will continue to be left with more sorrow, more loss and more pain.”

“Although this extreme seismic event affected a relatively small area of the planet, its impacts have reverberated around the world. The rapidly growing humanitarian aid effort to assist those most deeply affected is a testament to the willingness of people to lend their support to those now facing the resulting humanitarian crisis.” said Helen Glaves, EGU President. “Although the extent of the death and destruction resulting from this extreme seismic event will not be known for many days, weeks and months to come, EGU would like to send a message of support and condolence to those communities that have been directly affected by this terrible natural disaster.”

To stay up to date with information about this event as it becomes available, please follow this link provided by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, Boğaziçi University.

• Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, Boğaziçi University updates including preliminary report
• USGS record of 7.8Mw earthquake, Turkey, 6 February 2023
• USGS record of 7.5Mw earthquake, Turkey, 6 February 2023