The 2006 Kythira (Greece), Mw6.7 slab-pull event: tectonic implications and the geometry of the hellenic wadati-benioff zone

A strong (Mw=6.7) intermediate depth earthquake occurred on 8 January 2006 (11:34 UTC) in southwestern Aegean Sea (Greece) causing limited damage to structures on the nearby islands of Kythira and Antikythira, as well as western Crete Island. The epicentral area belongs to the SW segment of the Hellenic Arc, which is known to be associated with the occurrence of large shallow and intermediate depth earthquakes, mainly due to the subduction of the Eastern Mediterranean oceanic lithosphere under the Aegean microplate. The main shock occurred on a dextral strike slip fault at a depth of 75 km, within the descending slab, as it is revealed by both, the spatial distribution of the accurately located aftershocks and its fault plane solution determined in the present study and implying a slab-pull event. The aftershock activity from 8 to 31 January 2006 is distributed in depths ranging from 55 to 75 km, and being comprised in an almost rectangular and vertical plane with a length equal to 28 km and a width of 20 km, which adequately defines the dimensions of the rupture area. The geometry of the Wadati-Benioff zone in this area, namely the southwestern part of the Hellenic Arc, is explored by an exhaustive analysis of all the available phase arrivals gathered from the International Seismological Centre, and the relocation of the earthquakes occurred since 1964 in the South-West Aegean region

Velocity models inferred from p-waves travel time curves in south Aegean

Με σκοπό τη δημιουργία μοντέλων ταχύτητας στην περιοχή του νοτίου Αιγαίου, χρησιμοποιούμε τις καταγραφές σεισμών κατά τη χρονική περίοδο από 1η Ιανουαρίου έως 3Ιη Αυγούστου 2005 από ένα νέο τηλεμετρικό δίκτυο που εγκαταστάθηκε και λειτουργεί στην περιοχή της Κρήτης. Τα μοντέλα ταχύτητας κατασκευάζονται από τις καμπύλες χρόνων διαδρομής των επιμηκών κυμάτων και χρησιμοποιούνται σε συνδυασμό με τις χρονικές διορθώσεις στο χρόνο άφιξης των σεισμικών κυμάτων σε κάθε σεισμολογικό σταθμό του δικτύου για τον ακριβή προσδιορισμό των εστιακών παραμέτρων των σεισμών που έχουν καταγραφεί στην περιοχή του νοτίου Αιγαίου με τη χρήση του προγράμματος HYPOINVERSE. Συνδυάζοντας όλες τις διαθέσιμες πληροφορίες από τη βιβλιογραφία και τα αποτελέσματα της παρούσας μελέτης προσδοκούμε να συμβάλουμε στην αποσαφήνιση του σεισμοτεκτονικού προτύπου της περιοχής καθώς και της γεωμετρίας της καταδυόμενης λιθόσφαιρας της ανατολικής Μεσογείου.The seismicity recorded during Ist January to 31st August 2005 from a new telemetry network installed and operating on the island of Crete, is used in an effort to obtain new velocity models for the area of south Aegean. The models are constructed from the P-waves travel time curves and are later used for the events relocation with the HYPOINVERSE algorithm and station delays calculation. Furthermore, results are discussed and compared with the ones derived from other significant previous works presented the last years. We anticipate by combining all the available information from the literature and the analysis of our data set to contribute to the seismotectonic modeling of the study area and to construct a most complete image of the geometry of the subducted plate

THGEM-based detectors for sampling elements in DHCAL: laboratory and beam evaluation

We report on the results of an extensive R&D program aimed at the evaluation of Thick-Gas Electron Multipliers (THGEM) as potential active elements for Digital Hadron Calorimetry (DHCAL). Results are presented on efficiency, pad multiplicity and discharge probability of a 10x10 cm2 prototype detector with 1 cm2 readout pads. The detector is comprised of single- or double-THGEM multipliers coupled to the pad electrode either directly or via a resistive anode. Investigations employing standard discrete electronics and the KPiX readout system have been carried out both under laboratory conditions and with muons and pions at the CERN RD51 test beam. For detectors having a charge-induction gap, it has been shown that even a ~6 mm thick single-THGEM detector reached detection efficiencies above 95%, with pad-hit multiplicity of 1.1-1.2 per event; discharge probabilities were of the order of 1e-6 - 1e-5 sparks/trigger, depending on the detector structure and gain. Preliminary beam tests with a WELL hole-structure, closed by a resistive anode, yielded discharge probabilities of <2e-6 for an efficiency of ~95%. Methods are presented to reduce charge-spread and pad multiplicity with resistive anodes. The new method showed good prospects for further evaluation of very thin THGEM-based detectors as potential active elements for DHCAL, with competitive performances, simplicity and robustness. Further developments are in course.Comment: 15 pages, 11 figures, MPGD2011 conference proceedin

Microearthquake study of the broader Thessaloniki area (Northern Greece)

A temporary network of twelve portable digital seismological stations was operated around the city of Thessaloniki (Northern Greece) for a period of 19 months (from July 2001 to April 2002 and from October 2002 to August 2003), providing data that enabled the study of the interconnection between microseismicity and active tectonics in the area. During the operation period 277 microearthquakes that were recorded in more than four stations were accurately located and 64 fault plane solutions were determined. Seismic activity is associated with ENE-WSW, E-W and ESE-WNW striking normal faults and is nearly confined to the first 15 km, thus defining the seismogenic layer in the study area. The mean orientation of the axis of maximum extension (T-axis) is NS to NNE-SSW, determined from fault plane solutions, in agreement with the regional extensional stress pattern, which strikes perpendicular to the orientation of the main WNW-ESE active faults of the area

Microearthquake study of the broader Thessaloniki area (Northern Greece)

A temporary network of twelve portable digital seismological stations was operated around the city of Thessaloniki (Northern Greece) for a period of 19 months (from July 2001 to April 2002 and from October 2002 to August 2003), providing data that enabled the study of the interconnection between microseismicity and active tectonics in the area. During the operation period 277 microearthquakes that were recorded in more than four stations were accurately located and 64 fault plane solutions were determined. Seismic activity is associated with ENE-WSW, E-W and ESE-WNW striking normal faults and is nearly confined to the first 15 km, thus defining the seismogenic layer in the study area. The mean orientation of the axis of maximum extension (T-axis) is NS to NNE-SSW, determined from fault plane solutions, in agreement with the regional extensional stress pattern, which strikes perpendicular to the orientation of the main WNW-ESE active faults of the area

Hazard-consistent response spectra in the Region of Murcia (Southeast Spain): comparison to earthquake-resistant provisions

Hazard-consistent ground-motion characterisations of three representative sites located in the Region of Murcia (southeast Spain) are presented. This is the area where the last three damaging events in Spain occurred and there is a significant amount of data for comparing them with seismic hazard estimates and earthquake-resistant provisions. Results of a probabilistic seismic hazard analysis are used to derive uniform hazard spectra (UHS) for the 475-year return period, on rock and soil conditions. Hazard deaggregation shows that the largest hazard contributions are due to small, local events for short-period target motions and to moderate, more distant events for long-period target motions. For each target motion and site considered, the associated specific response spectra (SRS) are obtained. It is shown that the combination of two SRS, for short- and long-period ground motions respectively, provides a good approximation to the UHS at each site. The UHS are compared to design response spectra contained in current Spanish and European seismic codes for the 475-year return period. For the three sites analysed, only the Eurocode 8 (EC8) type 2 spectrum captures the basic shape of the UHS (and not the EC8 type 1, as could be expected a priori). An alternative response spectrum, anchored at short- and long-period accelerations, is tested, providing a close match to the UHS spectra at the three sites. Results underline the important contribution of the frequent, low-to-moderate earthquakes that characterize the seismicity of this area to seismic hazard (at the 475-year return period)

Vitamin-V: Virtual Environment and Tool-boxing for Trustworthy Development of RISC-V based Cloud Services

Vitamin-V is a 2023-2025 Horizon Europe project that aims to develop a complete RISC-V open-source software stack for cloud services with comparable performance to the cloud-dominant x86 counterpart and a powerful virtual execution environment for software development, validation, verification, and test that considers the relevant RISC-V ISA extensions for cloud deployment

Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at s√=8 TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. The search is based on proton-proton collision data at a centre-of-mass energy s√=8 TeV collected in 2012, corresponding to an integrated luminosity of 20 fb−1. No significant excess above the Standard Model expectation is observed. Limits are set on supersymmetric particle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV. Limits are also set on the parameters of a minimal universal extra dimension model, excluding a compactification radius of 1/R c = 950 GeV for a cut-off scale times radius (ΛR c) of approximately 30