Geodetic Source Modeling of the 2019 M_w 6.3 Durrës, Albania, Earthquake: Partial Rupture of a Blind Reverse Fault

Abstract

We address geometric and kinematic properties of the M w 6.3 26 November 2019 Durrës earthquake, the strongest earthquake in Albania in the past 40 years. Using coseismic surface displacements from Sentinel-1 Differential Interferometric Synthetic Aperture Radar (DInSAR) and nearby Global Navigational Satellite System (GNSS) stations, we invert for the geometry and slip of the causative fault. We find that both a steep SW-dipping fault (dip 71°) and a shallow NE-dipping fault (dip 15°) can fit the data equally well. However, the slip on the SW-dipping fault occurs at depths 11-23 km, similar to the depths of the mainshock and aftershock seismicity, and thus, we prefer that model. The location of our preferred fault plane correlates with the mapped SW-dipping backthrust, the Vore fault. The fault rupture did not reach the surface, which implies that an updip stress propagation onto the unruptured shallow portion of the Vore fault and its secondary structures pose an increased seismic hazard for cities in Albania, including the capital, Tirana.

The Upper Crustal Deformation Field of Greece Inferred From GPS Data and Its Correlation With Earthquake Occurrence

“…We note that the compressional axis becomes notably larger compared to the corresponding extensional axis in the epicentral area of the 2019 M w 6.3 Durrës earthquake. At this region we resolve a NE‐SW oriented compression of 45 nstrain/yr, which is consistent with the NW‐SE trending reverse fault that ruptured during the 2019 mainshock (e.g., Govorčin et al., 2020; Pezzo et al., 2022). The other region where the strain rate field is dominated by compression lies in northwestern Greece and, more specifically, in western Epirus and Paxoi Islands.…”

Rotation at subduction margins: How complexity at fault‐scale (the 2019 Albanian Mw 6.4 earthquake) mirrors the regional deformation

“…Ganas et al (2020) and Vittori et al (2021) favour an E‐dipping fault, consistent with the activation of a deep‐blind‐low‐angle thrust. Govorčin et al (2020) discussed both geometries and supported the activation of a blind‐high‐angle back‐thrust, namely the Vore back‐thrust. The east‐dipping plane, with a great depth of 20 km and low dip angle, is not an obvious feature of the regional structural setting (see also Vittori et al, 2021), decoupled from the shallower east‐verging thrust system and poorly known or constrained.…”

“…This earthquake is part of a seismic sequence spreading from late 2019 to early 2020 with 8 M w > 5 reverse FMs with belt‐perpendicular P ‐axes. Due to a rather sparse aftershock distribution and absence of primary surface coseismic ruptures (Papadopoulos et al, 2020), previous studies modelled the mainshock as either a low‐angle ENE‐dipping thrust (Caporali et al, 2020, Ganas et al, 2020, Papadopoulos et al, 2020; Vittori et al, 2021) or a SW‐dipping back‐thrust (Govorčin et al, 2020).…”

Systematic Comparison of InSAR and Seismic Source Models for Moderate‐Size Earthquakes in Western China: Implication to the Seismogenic Capacity of the Shallow Crust

“…In addition, the 6‐year period only covers a small portion of the long earthquake cycle, and our investigation focuses on a single tectonic region. Despite these possible limits, we believe the considerable moments released in the uppermost crust could be a general conclusion, based on the observations that more and more shallow earthquakes in other continents have been reported with InSAR data (e.g., Dawson et al., 2008; Govorčin et al., 2020; Materna et al., 2019; Motagh et al., 2015; Ritz et al., 2020; Wei et al., 2015). The findings in this study have shown the great potential of an InSAR‐based earthquake catalog.…”