Ionospheric response to the 2020 Samos earthquake and tsunami

The version of record of this article, first published in Earth, planets and space, is available online at Publisher’s website: http://dx.doi.org/10.1186/s40623-023-01940-2On 30 October 2020 at 11:51 UT, a magnitude 7.0 earthquake occurred in the Dodecanese sea (37.84°N, 26.81°E, 10 km depth) and generated a tsunami with an observed run-up of more than 1 m on the Turkish coasts. Both the earthquake and the tsunami produced acoustic and gravity waves that propagated upward, triggering co-seismic and co-tsunamic ionospheric disturbances. This paper presents a multi-instrumental study of the ionospheric impact of the earthquake and related tsunami based on ionosonde data, ground-based Global Navigation Satellite Systems (GNSS) data and data from DORIS beacons received by Jason3 in the Mediterranean region. Our study focuses on the Total Electron Content to describe the propagation of co-seismic and co-tsunami ionospheric disturbances (CSID, CTID), possibly related to gravity waves triggered by the earthquake and tsunami. We use simultaneous vertical ionosonde soundings to study the interactions between the upper and lower atmosphere, highlighting the detection of acoustic waves generated by the seismic Rayleigh waves reaching the ionosonde locations and propagating vertically up to the ionosphere. The results of this study provide a detailed picture of the Lithosphere-Atmosphere–Ionosphere coupling in the scarcely investigated Mediterranean region and for a relatively weak earthquake.Upper Atmosphere Physics and Radiopropagation Working Group, Marcocci, C., Pezzopane, M., Pica, E., Romano, V., Sabbagh, D., Scotto, C., & Zuccheretti, E. (2020). Electronic Space Weather upper atmosphere database (eSWua)—HF data, version 1.0 (1.0). Istituto Nazionale di Geofsica e Vulcanologia (INGV). https://doi.org/https://doi.org/10.13127/ESWUA/HF. GNSS stations providers: (a) Uranus network (http://uranus.gr) operated by the Tree Company corpora‑ tion National Observatory of Athens (NOA) network, http://geodesy.gein.noa. gr:8000/nginfo/ (Ganas et al. 2008; Chousianitis et al. 2021). HxGN SmartNet operated by the Metrica SA (https://www.metrica.gr). (b) Turkish National Permanent GNSS Network-Active (TNPGN-Active/CORS-TR) https://www. tusaga-aktif.gov.tr/. (c) The DORIS measurements and orbits were obtained from https://cddis.gsfc.nasa.gov/archive/doris/data. The authors thank Dr. Laura Scognamiglio and Dr. Paola Baccheschi from INGV for their support to interpret the seismograms. Anna Belehaki acknowledges fnancial support provided by the PITHIA-NRF Horizon 2020 Grant Agreement 101007599 of the European Commission. Elvira Astafyeva acknowledges the support of the French National Research Agency (ANR), project IONO-DIET (Grant ANR22-CE49-0011), and the French Space Agency (CNES), project “RealDetect”.Peer ReviewedPostprint (published version

Reykjanes 2021

Mapping and analysis of the ground fracturing following the 2021 Fagradlasfjall seismo-volcanic unres

Fracture mapping

East Zone: Mapping of the surface fractures of the East Zone, where the nature of the ground was the most favorable to the expression of the surface cracks. The black lines mark each surface crack, mapped at a 1:80 scale in QGIS on the orthomosaics processed from the Wingtra UAV imagery. West Zone: field mapping of the March 7, 2021, Mw=5.1 surface rupture

The sprawl of the External Hellenides: from post-Alpine collapse to present-day kinematics

International audienceDuring the Neogene, the Aegean domain underwent intense deformation, leading to a thinning by a factor of two or more of the Alpine orogenic prism. Today, tectonic velocity gradients are still among the fastest in Europe due to the Anatolian extrusion induced by the Arabian indentation and by the Hellenic slab retreat. The present-day deformation essentially localizes in the subduction backstop. With respect to the central Aegean, which is almost stable today, this still-thick buttress has remained at a much earlier and brittle deformation stage. This is particularly the case in the ~east–west-extending External Hellenides (Southern Greece), shaped by a series of major NNW–SSE-oriented normal faults.How has the crustal deformation been accommodated by the various fault systems present in the Peloponnese since the Paleogene? Which of those fault systems are still active today? To what extent can boundary forces such as the Hellenic slab pull be sufficient to explain this extension? Thanks to a significant increase in the GNSS network density in the Peloponnese, we present an updated local strain field. The resulting strain confirms the ~east–west sprawl of the External Hellenides, with extension also, to a lesser extent, in the other directions. Through identifying low-angle detachments by field and satellite morpho-structural analysis, we show that this spreading has been occurring since the Pliocene, mostly by reusing décollement layers of the Alpine nappes as extensional structures. We suggest that the main high-angle normal faults existing in the Peloponnese correspond to a localization of the extension in the weakest azimuth dictated by the Alpine backbone. We propose that this surface sprawl results not only from the Hellenic slab retreat but also from the exhumation of the deep Peloponnesian stacked units, and the subsequent crustal gravity collapse

Ionospheric response to the 2020 Samos earthquake and tsunami

International audienceOn 30 October 2020 at 11:51 UT, a magnitude 7.0 earthquake occurred in the Dodecanese sea (37.84°N, 26.81°E, 10 km depth) and generated a tsunami with an observed run-up of more than 1 m on the Turkish coasts. Both the earthquake and the tsunami produced acoustic and gravity waves that propagated upward, triggering co-seismic and co-tsunamic ionospheric disturbances. This paper presents a multi-instrumental study of the ionospheric impact of the earthquake and related tsunami based on ionosonde data, ground-based Global Navigation Satellite Systems (GNSS) data and data from DORIS beacons received by Jason3 in the Mediterranean region. Our study focuses on the Total Electron Content to describe the propagation of co-seismic and co-tsunami ionospheric disturbances (CSID, CTID), possibly related to gravity waves triggered by the earthquake and tsunami. We use simultaneous vertical ionosonde soundings to study the interactions between the upper and lower atmosphere, highlighting the detection of acoustic waves generated by the seismic Rayleigh waves reaching the ionosonde locations and propagating vertically up to the ionosphere. The results of this study provide a detailed picture of the Lithosphere-Atmosphere-Ionosphere coupling in the scarcely investigated Mediterranean region and for a relatively weak earthquake

The 2020–2021 seismic sequence in the Western Gulf of Corinth: Insights on the triggering mechanisms through high resolution seismological and geodetic data analysis

International audienc

An Atypical Shallow Mw 5.3, 2021 Earthquake in the Western Corinth Rift (Greece)

International audienc

The Western Gulf of Corinth (Greece) 2020–2021 Seismic Crisis and Cascading Events: First Results from the Corinth Rift Laboratory Network

International audienceAbstract We investigate a seismic crisis that occurred in the western Gulf of Corinth (Greece) between December 2020 and February 2021. This area is the main focus of the Corinth Rift Laboratory (CRL) network, and has been closely monitored with local seismological and geodetic networks for 20 yr. The 2020–2021 seismic crisis evolved in three stages: It started with an Mw 4.6 event near the northern shore of the Gulf, opposite of Aigion, then migrated eastward toward Trizonia Island after an Mw 5.0 event, and eventually culminated with an Mw 5.3 event, ∼3 km northeast of the Psathopyrgos fault. Aftershocks gradually migrated westward, triggering another cluster near the junction with the Rion–Patras fault. Moment tensor inversion revealed mainly normal faulting; however, some strike-slip mechanisms also exist, composing a complex tectonic regime in this region dominated by east–west normal faults. We employ seismic and geodetic observations to constrain the geometry and kinematics of the structures that hosted the major events. We discuss possible triggering mechanisms of the second and third stages of the sequence, including fluids migration and aseismic creep, and propose potential implications of the Mw 5.3 mainshock for the seismic hazard of the region