Moderate Earthquakes of Korçë — Leskovik Seismogenic Zone in Albania During This Century

Abstract: Albania is situated in Alpine-Mediterranean seismic belt comprising the zone of contact between lithosphere plates of Africa and Eurasia. The main cause of Albanian seismicity is the collision of Adria microplate with the Albanian orogeny. Albanian territory is characterized with high level of seismic hazard in the Europe. The earthquakes foci are concentrated mostly along the active faults and low velocity zones. In this century, seismic activity in the Leskovik-Korça-Ohrid (LKO) fault zone has been dominated by seven moderate earthquakes, with magnitudes (ML) ranging from 4.5 to 5.3. Additionally, in the Leskovik-Korça-Ohrid region, there have been approximately 30 earthquakes with ML ≥ 4.0, and 7 earthquakes with ML ≥ 4.5, including 4 earthquakes with ML ≥ 5.0. A series of earthquakes, including the maximum magnitude event (ML = 5.3), began on June 1, 2019, at 04:26 (UTC) near Floq village, about 17 km southwest of Korça, highlighting the increased seismic activity in the Leskovik-Korça-Ohrid seismogenic zone. The focal mechanism analysis reveals that in southeastern Albania, the dominant faulting type is normal faulting with a strike-slip component. This faulting occurs in the direction of N to S extension and is associated with the convergence between the Adriatic microplate and the Albanian orogen. The focal mechanisms solution of 8 moderate earthquakes during this century indicate that the extensional regime was the main cause of the seismic activity along the inner Albanides. This study presents an analysis of the focal mechanisms of seismic events. Together with the strongest earthquake, which occurred in May 1960 (M = 6.2), this activity forms a roughly N–S trending active seismotectonic zone in southeastern Albania, posing a significant seismic threat to nearby urban areas in Albania, Greece, and North Macedonia.