On March 3, 2021 a Mw=6.3 shallow earthquake occurred in the mountainous region of Damasi, about 20 km to the northwest of Larisa, Thessaly, central Greece, in a region of active crustal extension but of low strain. This event was followed by a Mw=6.0 shallow earthquake on March 4, 2021 about 12 km to the northwest, inside the sedimentary basin of the Titarisios river. On March 12, 2021 a third event of Mw=5.6 occurred 7 km further towards NNW, near the NW edge of the basin. All events show normal-slip kinematics as indicated by the moment tensor solutions, with minor strike-slip components. Because of the shallow depth of the events it was possible to map the surface deformation using InSAR. The preliminary results from InSAR show three main lobes of subsidence, partially overlapping. The deformation pattern indicates the activation of three normal faults, previously unknown in this part of Thessaly. The earthquakes generated numerous secondary phenomena with vast areas of alluvial deposits exhibiting spectacular liquefaction features. No tectonic ruptures were found in the cases of events 2 and 3, however a series of sporadic, NW-SE striking surface breaks were found on the mountains north of village Zarko that are aligned with the vanishing gradient of the interferometric phase of the 1st event.

Partially funded by the joint research - industry project MIS-5070928, financed by the EU and the Greek Government