The March 2021 Tyrnavos, central Greece, doublet (Μw6.3 and Mw6.0): Aftershock relocation, faulting details, coseismic slip and deformation (EN)

Galanis, Odysseus

Vamvakaris, Dominikos

Ventouzi, Chrysanthi

Bitharis, Stylianos

Foumelis, Michael

Pikridas, Christos

Fotiou, Aristeidis

Paradisopoulou, Parthena

Papazachos, Costas

Hatzidimitriou, Panagiotis

Papadimitriou, Eleftheria

Kourouklas, Christos

Kiratzi, Anastasia

Grendas, Ioannis

Karakaisis, George

Kementzetzidou, Despoina

Chatzipetros, Alexandros

Kostoglou, Anastasios

Karakostas, Vasileios

Panou, Areti

Karagianni, Eleni

Chatzis, Nikolaos

Kkallas, Charalambos

Scordilis, Emmanuel

Bonatis, Pavlos

Karagianni, Ioanna

On 3 March 2021, the Mw6.3 Tyrnavos earthquake shook much of the Thessalia region, leading to extensive damage in many small towns and villages in the activated area. The first main shock was followed in the next day, on 4th of March 2021, by an “equivalent” main shock with Mw6.0 in the adjacent fault segment. These are the largest earthquakes to strike the northeastern part of Thessalia since the M6.3, 1941 Larissa earthquake. The main shocks triggered extensive liquefaction mainly along the banks of the Titarisios tributary where alluvial flood deposits most probably amplified the ground motions. Our seismic monitoring efforts, with the use of recordings of the regional seismological network along with a dense local network that was installed three days after the seismic excitation initiation, led to the improved understanding the geometry and kinematics of the activated faults. The aftershocks form a north–northwest–trending, east–northeast–dipping, ~40 km long distribution, encompassing the two main ruptures along with minor activated structures, consistent with the rupture length estimated from analysis of regional waveform data and InSAR modeling. The first rupture was expanded bilaterally, the second main shock nucleated at its northern tip, where from this second rupture propagated unilaterally to the north–northwest. The focal mechanisms of the two main shocks support an almost pure normal faulting, similar to the aftershocks fault plane solution determined in this study. The strong ground motion of the March 3 main shock was computed with a stochastic simulation of finite fault model. Coseismic displacements that were detected using a dense GPS / GNSS network of five permanent stations located the Thessaly region, have shown an NNE–SSW extension as expected from the nature and location of the causative fault. Coulomb stress changes due to the coseismic slip of the first main shock, revealed that the hypocentral region of the second main shock was brought closer to failure by more than 10 bars. (EN)

info:eu-repo/semantics/article

info:eu-repo/semantics/publishedVersion

finite-fault slip model (EN)

seismic sequence (EN)

stress transfer and triggering (EN)

seismological geodesy (EN)

Ελληνική Γεωλογική Εταιρεία

Δελτίο της Ελληνικής Γεωλογικής Εταιρίας

Natural Hazards

Δελτίο της Ελληνικής Γεωλογικής Εταιρίας

Αγγλική γλώσσα

2021-08-24

https://ejournals.epublishing.ekt.gr/index.php/geosociety/article/view/27237

Geological Society of Greece (EN)

0438-9557

2529-1718

Δελτίο της Ελληνικής Γεωλογικής Εταιρείας; Τόμ. 58 (2021): Special Issue on the 2021 Northern Thessaly, Greece, Earthquake Sequence; 131-178 (EL)

Bulletin of the Geological Society of Greece; Vol. 58 (2021): Special Issue on the 2021 Northern Thessaly, Greece, Earthquake Sequence; 131-178 (EN)

https://creativecommons.org/licenses/by-nc/4.0 (EN)

Copyright (c) 2021 Vasileios Karakostas, Costas Papazachos, Eleftheria Papadimitriou, Michael Foumelis, Anastasia Kiratzi, Christos Pikridas, Anastasios Kostoglou, Charalambos Kkallas, Nikolaos Chatzis, Stylianos Bitharis, Alexandros Chatzipetros, Aristeidis Fotiou, Chrysanthi Ventouzi, Eleni Karagianni, Pavlos Bonatis, Christos Kourouklas, Parthena Paradisopoulou, Emmanuel Scordilis, Dominikos Vamvakaris, Ioannis Grendas, Despoina Kementzetzidou, Areti Panou, George Karakaisis, Ioanna Karagianni, Panagiotis Hatzidimitriou, Odysseus Galanis (EN)