A Mw6.9 earthquake in the Aegean Sea

Today (2014-05-24) on 09:25 UTC an earthquake with magnitude MW6.9 occurred in the NE Aegean Sea. The EMSC reports a depth of 27 km (USGS: 10 km). The quake had a (right-lateral) strike-slip mechanism and was felt as far away as Athens, Istanbul, and Sofia. More than 200 people were injured, most of them only lightly, and moderate damage to dozens of houses has been reported. The earthquake occurred on the (S)Western part of the North Anatolian Fault in the Samos Basin and was among the strongest events that have ever been recorded at that segment.

Earthquake location and moment tensor solutions. Credit: EMSC

A large number of aftershocks has been recorded, some of which exceeded M5.0:

Mainshock and aftershock distribution as of 21:00 UTC, 24 May. Credit: EMSC

First videos show the intensity of the shaking and document building damage:

This segment of the North Anatolian Fault Zone (NAFZ) is known to have the potential to generate even larger events. Papanikolaou and Papanikolaou (2007) investigated possible seismic sources and conclude that the worst case scenario is a M7.6 quake. Reicherter et al. (2010) identified tsunamites in the nearby Thermaikos Gulf area. Modelling suggest that a quake on the southwesternmost part of the NAFZ could be the tsunami source. Wait, isn’t it a strike-slip fault? Yes, but in the North Aegean Basin there the fault likely slips oblique. For the recent earthquake no anomalous waves have been reported so far. The quake was also almost pure strike-slip, which makes the triggering of a tsunami rather unlikely. Some submarine slides may still have occurred.

Structural setting of the North Aegean Basin, the NAFZ and the Thermaikos Gulf. The recent earthquake’s epicentre was close to the island of Samothrace. (After: Reicherter et al., 2010)
Tsunami modelling results of Reicherter et al. (2010).
Drilling campaign at the Thermaikos Gulf in 2007. Is it a tsunamite or not? (Photo by Carlo Schneider)
Drilling campaign at the Thermaikos Gulf in 2007. It ain’t over ’til it’s over. Credit: Carlo Schneider

If you want to know more about the active faults in Greece, make sure to check out the GreDaASS project – the Greek Database of Seismogenic Sources.

References and further reading:

  • Caputo, R., Chatzipetros, A., Pavlides, S., & Sboras, S. (2013). The Greek Database of Seismogenic Sources (GreDaSS): state-of-the-art for northern Greece. Annals of Geophysics, 55(5).
  • Papanikolaou, I. D., & Papanikolaou, D. I. (2007). Seismic hazard scenarios from the longest geologically constrained active fault of the Aegean. Quaternary international, 171, 31-44.
  • Reicherter, K., Papanikolaou, I., Roger, J., Mathes-Schmidt, M., Papanikolaou, D., Rössler, S., Grützner, C. & Stamatis, G. (2010). Holocene tsunamigenic sediments and tsunami modelling in the Thermaikos Gulf area (northern Greece). Zeitschrift für Geomorphologie, Supplementary Issues, 54(3), 99-125.

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