On Tuesday 22 May 2012, sightly after 3.00 am local time (slightly after midnight GMT), western Bulgaria was shaken by an Earthquake centered on the village of Meshtitsa, 24 km west of the capitol, Sofia. The quake was recorded as measuring 5.6 on the Richter Scale at a depth of 9.4 km by the United States Geological Survey, and 5.8 on the Richter Scale at a depth of 10 km by the Bulgarian National Seismological Data Center. The quake was felt across western Bulgaria, including in Sophia, as well as in the neighboring states of Serbia, Macedonia, Romania and Greece. There are no reported casualties, but there was localized damage to houses, a widespread panic during the quake has been reported in the press. The area has been hit by a number of aftershocks, though none as large as the original quake.
Map showing the location of the 22 May 2012 quake. USGS.
The geology of the Balkan Peninsula is complex. Bulgaria lies on the Eurasian Plate, but it is surrounded by a number of microplates created by the collision of Africa with Europe from the south. Southern Greece lies on the Aegean Sea Plate, a breakaway part of the Eurasian Plate, which is being pushed to the southwest by the westward movement of the Anatolian Plate, another breakaway part of the Eurasian Plate underlying Turkey. This is in turn being pushed west by the northeasterly motion of the Arabian Plate, a breakaway part of the African Plate. The western part of the Balkan Peninsula, and the eastern part of Italy are underlain by the Adriatic (or Apulian) Plate, a breakaway part of the African Plate which has pushed like a wedge into southern Europe.
Map showing the movement of the microplates of the eastern Mediterranean. Kotzev et al. (1998).
Thus the rocks of Bulgaria are being pulled to the southwest by the movement of the Aegean Sea Plate and pushed to the northeast by the movement of the Apulian Plate. This has resulted in a number of faults bisecting the country, forming the Pernic Fault Zone, the Vitosha Fault Zone, the Zheleznitsa Fault Zone and the Sophia Graben (a Graben is an area of geological extension). The 22 May Earthquake is thought to have been caused by movement along the Pernic Fault.
Map showing the extensive faulting across Bulgaria. Bulgarian Academy of Science
See also Earthquake on the Modena Plane, northern Italy, Earthquake in northern Algeria, Southwest Poland hit by Earthquake, Zurich shaken by mild Earthquake and Earthquakes on Sciency Thoughts YouTube.
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