Last night was difficult for the residents of Istanbul, following the 6.2-magnitude earthquake and over 120 aftershocks. Thousands of families were forced to spend the night in tents set up in parks, lighting fires to keep warm as temperatures dropped below 10°C.

Around 150 people were injured after falling from buildings during the strong tremor and were taken to hospitals. There were no building collapses or fatalities reported.

Residents described the main quake as one of the strongest they had experienced in years, expressing fears of an even more powerful earthquake to come.

Potential Damage to Hagia Sophia if Seismic Activity Continues

The earthquake brought back memories of 1999, when a major 7.8-magnitude quake struck the area, followed days later by the Athens earthquake triggered by the Parnitha fault.

According to Efthymis Lekkas, President of Greece’s Earthquake Planning and Protection Organization (OASP), the Marmara fault – the source of yesterday’s strong tremor – is capable of producing quakes up to magnitude 7. Speaking on ERT News, he warned that continued seismic activity could potentially damage the Hagia Sophia.

“This quake is not expected to activate tectonic structures in the Hellenic region, unless we’re dealing with larger magnitudes, in which case we’ll need to reassess the impact on Greece,” he noted.

Three Scenarios for the 1,500-kilometer Fault

“A small segment of the fault ruptured and caused the 6.2 quake, but a significant amount of energy remains unspent. There are three possible scenarios,” explained Lekkas.

  • Scenario one: This was the main quake, followed by numerous aftershocks.
  • Scenario two: The 6.2 quake is followed by an even larger quake, possibly up to magnitude 7.
  • Scenario three: A sequence of about 30 quakes around magnitude 6 gradually releases the built-up energy.

“If the latter sequence continues, we may see some damage to the Hagia Sophia,” Lekkas added, also warning that up to one-third of Istanbul’s building stock—particularly older structures 50–100 years old—could be at risk of collapse.

“The Marmara fault is the tail end of the major North Anatolian fault, one of the most active fault lines in the world, stretching 1,500 kilometers from Bingöl province in eastern Turkey to just 20 kilometers outside Istanbul, ending in the northern Aegean Sea.”

“It’s the segment that hasn’t ruptured yet and has been expected to for the past five years. The longer it delays, the more energy it accumulates. A small part has now been activated, but the rest remains,” Lekkas said.

Since 1939, this fault has produced seven quakes above magnitude 7 in Turkey, resulting in tens of thousands of deaths—many from people jumping out of windows in a desperate attempt to escape.

Nightmarish Warning of a Magnitude 7 Quake

A powerful 7.0-magnitude earthquake is still likely, warned Turkish geologist Professor Naci Görür.

Following the series of tremors that shook Istanbul on April 23, the professor stressed the possibility of another major quake and emphasized the importance of coordination between the government, municipalities, and citizens.

“There are many quakes of varying magnitudes along the Kumburgaz fault in the Sea of Marmara. These are not the large quakes we’re expecting in Marmara. But they increase the pressure building on the fault. The real quake will be larger – above magnitude 7,” he posted on X.

“It’s important that we don’t only talk about earthquakes when they happen. We need to discuss them when there is no quake and take precautions. Government, municipalities, and the public must work hand-in-hand to prepare the city,” he stated.

He added: “Urban development and new buildings alone won’t prepare a city for a quake. A seismically resilient city is something entirely different. Citizens must do what’s necessary, monitor and ensure enforcement.”