Some Contributions of the Neo-Deterministic Seismic Hazard Assessment Approach to Earthquake Risk Assessment for the City of Sofia

• Published in: Pure and applied geophysics Vol. 168; no. 3-4; pp. 521 - 541
• Main Authors: Paskaleva, Ivanka, Kouteva-Guentcheva, Mihaela, Vaccari, Franco, Panza, Giuliano F.
• Format: Journal Article
• Language: English
• Published: Basel SP Birkhäuser Verlag Basel 01.03.2011; Springer Nature B.V
• Subjects: Earth and Environmental Science; Earth Sciences; Earthquakes; Geophysics; Geophysics/Geodesy; Hazards; Risk assessment; Seismology; Bulgaria, Sofia; earthquake scenario; neo-deterministic hybrid approach; Seismic hazard; seismic demand; damage index and vulnerability; ground motion modelling
• ISSN: 0033-4553; 1420-9136
• DOI: 10.1007/s00024-010-0127-8

This paper describes the outcome of the advanced seismic hazard and seismic risk estimates recently performed for the city of Sofia, based on the state-of-the-art of knowledge for this site. Some major results of the neo-deterministic, scenario-based, seismic hazard assessment approach (NDSHA) to the earthquake hazard assessment for the city of Sofia are considered. Further validations of the recently constructed synthetic strong motion database, containing site and seismic source-specific ground motion time histories are performed and discussed. Displacement and acceleration response spectra are considered. The elastic displacement response spectra and displacement demand are discussed with regard to earthquake magnitude, seismic source-to-site distance, seismic source mechanism, and local geological site conditions. The elastic response design spectrum from the standard pseudo-acceleration, versus natural period, T n , format, converted to a capacity diagram in S a  −  S d format is discussed in the perspective of the Eurocode 8 provisions. A brief overview of the engineering applications of the seismic demand obtained making use of the NDSHA is supplied. Some applications of the outcome of NDSHA procedure for engineering purposes are shown. The obtained database of ground shaking waveforms and time-histories, computed for city of Sofia is used to: (1) extract maximum particle velocities; (2) calculate the space distribution of the horizontal strain factor Log 10   ε ; (3) estimate liquefaction susceptibility in terms of standard penetration test, N values, and initial over burden stress; (4) estimate damage index distribution; and (5) map the distribution of the expected pipe breaks and red-tagged buildings for given scenario earthquakes, etc. The theoretically obtained database, based on the simultaneous treatment of the data from many disciplines, contains data fully suitable for practical use. The proper use of this database can lead to a significant seismic vulnerability reduction and thus contributes to earthquake preparedness.