Observations from the March 2021 Thessaly Earthquakes: an earthquake engineering perspective for masonry structures

Abstract

Two strong earthquakes hit Thessaly region on March 3rd, 2021 (Mw = 6.3) and on March 4th, 2021 (Mw = 6.1). The epicentres of the earthquakes were located at approximately 23 and 29 km respectively NW of Larissa, one of the most populous cities in Greece. Several aftershocks followed thereafter. Although no injuries were recorded, several structures suffered significant damage close to the epicentre, while some others collapsed. Approximately 300 residents of the village of Damasi were transferred to temporary settlements and tents. The event occurred during the COVID19 lockdown and created significant stress and disruption to residents. This paper focuses on the earthquake swarm itself as well as the damages observed in residential buildings, schools, and churches in the earthquake-stricken region. The earthquakes mainly impacted low-rise domestic masonry buildings, while the more modern reinforced concrete structures built following the recent seismic regulations were almost unaffected. The typology of buildings in the region, together with photographs demonstrating the extent of damage are presented herein. Despite the rather satisfactory performance of modern buildings in recent earthquakes in Greece, the preliminary investigations from the Thessaly Earthquakes showed that there is still a significant level of vulnerability in existing masonry building stock constructed using traditional methods and materials. This issue could re-emerge in future earthquakes striking other rural areas of Greece, something that needs to be addressed systematically in the future.

Seismic imaging of fluid-filled inherited structures of the Northern Thessaly (Greece) seismic gap

“…The source orientation of the Mw 5.6 event is still debated. Some authors have proposed a SW-dipping fault plane (De Novellis et al, 2021;Papadopoulos et al, 2021;Sarhosis et al, 2022;Yang et al, 2022), while Kontoes et al (2022) have recently proposed two possible fault plane solutions. Our analysis seems to be able to fix this point.…”

Complex analysis of earthquake deformations using SAR images: Examples from Croatia and Greece

“…The inset map indicates the position of the seismic faults composed in the European Database of Seismogenic Faults (EDSF) [11]. [13]. According to the EDSF the main earthquake`s epicenter is situated on the Tyrnavos fault with annual slip rate in the range between 0.05 -0.4 mm/y.…”

Potential non-disasters of 2021

“…The reported limited consequences suggest that a disaster was avoided. Further investigation would help to know building codes in place and adhered to (see Sarhosis et al. , 2022) alongside the local knowledge regarding earthquake-related behaviour before, during and after shaking.…”