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Kalogeras, Ioannis
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Kalogeras, Ioannis
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- PublicationOpen AccessThe October 9, 1996 earthquake in Cyprus: seismological, macroseismic and strong motion data(1999-02)
; ; ; ;Kalogeras, I.; National Observatory of Athens, Geodynamic Institute, Athens, Greece ;Stavrakakis, G.; National Observatory of Athens, Geodynamic Institute, Athens, Greece ;Solomi, K.; Ministry of Agriculture and Natural Resources, Geological Survey Department, Nicosia, Cyprus; ; On October 9, 1996, an earthquake of magnitude 6.8 occurred in the sea area SW of Cyprus, Eastern Mediterranean. This earthquake, which caused damage mostly in the area of Paphos and Limassol, triggered an accelerograph installed at Yermasoyia dam, north of Limassol. The Geodynamic Institute of the National Observatory of Athens in cooperation with the Geological Survey of Cyprus deployed five digital accelerographs in order to record large aftershocks. Although the aftershock activity lasted over four months and included a large number of earthquakes with magnitudes 4.5 and greater, only the largest aftershock of January 13, 1997, having a magnitude of 5.9, triggered two of these five accelerographs. Moreover another digital accelerograph, operated by the Water Development Department of Cyprus, was triggered and this record was also taken into account in this study. The first Cyprean strong motion records obtained to date, gave us the opportunity to compare the results from their analysis to the already proposed attenuation relationships from other areas of the world with a similar seismotectonic regime. Although a general fitting to the attenuation curves for subduction events and strike-slip/reverse fault events was found, the calculated peak ground accelerations were found to be lower than others. Unfortunately, due to the lack of data from previous Cyprean earthquakes, it was not possible to conclude to precise attenuation424 486 - PublicationOpen AccessThe Engineering Strong‐Motion Database: A Platform to Access Pan‐European Accelerometric Data(2016)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;This article describes the Engineering Strong-Motion Database (ESM), developed in the framework of the European project Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation (NERA, see Data and Resour- ces). ESM is specifically designed to provide end users only with quality-checked, uniformly processed strong-motion data and relevant parameters and has done so since 1969 in the Euro- Mediterranean region. The database was designed for a large variety of stakeholders (expert seismologists, earthquake engi- neers, students, and professionals) with a user-friendly and straightforward web interface. Users can access earthquake and station information and download waveforms of events with magnitude ≥ 4:0 (unprocessed and processed acceleration, velocity, and displacement, and acceleration and displacement response spectra at 5% damping). Specific tools are also available to users to process strong-motion data and select ground-motion suites for code- based seismic structural analyses.283 177 - PublicationRestrictedA physically based strong ground-motion prediction methodology; application to PSHA and the 1999 Mw = 6.0 Athens earthquake(2007-02)
; ; ; ; ; ; ; ; ;Hutchings, L.; Lawrence Livermore National Laboratory, Hazards Mitigation Center, PO Box 808, L-201, Livermore, CA 94551-0808, USA. ;Ioannidou, E.; Department of Geophysics-Geothermics, University of Athens, Athens 15783, Greece ;Foxall, W.; Lawrence Livermore National Laboratory, Hazards Mitigation Center, PO Box 808, L-201, Livermore, CA 94551-0808, USA. ;Voulgaris, N.; Department of Geophysics-Geothermics, University of Athens, Athens 15783, Greece ;Savy, J.; Lawrence Livermore National Laboratory, Hazards Mitigation Center, PO Box 808, L-201, Livermore, CA 94551-0808, USA. ;Kalogeras, I.; Institute of Geodynamics, National Observatory of Athens, Athens, Greece ;Scognamiglio, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Stavrakakis, G.; Institute of Geodynamics, National Observatory of Athens, Athens, Greece; ; ; ; ; ; ; We present a physically based methodology to predict the range of ground-motion hazard for earthquakes along specific faults or within specific source volumes, and we demonstrate how to incorporate this methodology into probabilistic seismic hazard analyses (PSHA). By ‘physically based,’ we refer to ground-motion syntheses derived from physics and an understanding of the earthquake process. This approach replaces the aleatory uncertainty that current PSHA studies estimate by regression of empirical parameters with epistemic uncertainty that is expressed by the variability in the physical parameters of the earthquake rupture. Epistemic uncertainty can be reduced by further research.We modelled wave propagation with empirical Green’s functions. We applied our methodology to the 1999 September 7 Mw = 6.0 Athens earthquake for frequencies between 1 and 20 Hz.We developed constraints on rupture parameters based on prior knowledge of the earthquake rupture process and on sources within the region, and computed a sufficient number of scenario earthquakes to span the full variability of ground motion possible for a magnitude Mw = 6.0 earthquake with our approach. We found that: (1) our distribution of synthesized ground motions spans what actually occurred and that the distribution is realistically narrow; (2) one of our source models generates records that match observed time histories well; (3) certain combinations of rupture parameters produced ‘extreme,’ but not unrealistic ground motions at some stations; (4) the best-fitting rupture models occur in the vicinity of 38.05!N, 23.60!Wwith a centre of rupture near a 12-km depth and have nearly unilateral rupture toward the areas of high damage, which is consistent with independent investigations.We synthesized ground motion in the areas of high damage where strong motion records were not recorded from this earthquake. We also developed a demonstration PSHA for a single magnitude earthquake and for a single source region near Athens. We assumed an average return period of 1000 yr for this magnitude earthquake and synthesized 500 earthquakes distributed throughout the source zone, thereby having simulated a sample catalogue of ground motion for a period of 500 000 yr. We then used the synthesized ground motions rather than traditional attenuation relations for the PSHA.201 28