StatusThe thesis was presented on the 24 April, 2015
Approved by NCAA on the 28 May, 2015
Abstract– 0.75 Mb / in romanian
Keywords: Earthquakes, seismicity, seismic source, magnitude and focal mechanisms, fault plane solution, catalogue of seismic parameters, velocity model, modal summation method, deterministic and neo-deterministic seismic hazard, Vrancea, Republic of Moldova (RM).
Field of study: Geophysics, seismology
Aim of study: deepening knowledge about Vrancea seismic phenomenon by studying seismicity and focal mechanism, to assess the impact of strong regional seismic events on RM territory.
Objectives: strengthening of the integral vision on understanding Vrancea seismic phenomenon by analyzing and synthesis of available results; study of focal mechanisms for Carpatic area seismic events; energy dimensionality assessment by studying the transfer relationships between different energy scales; the geophysical study of the regional structure and Vrancea-RM model development; the local (southern region of of RM, Cahul city) seismic impact assessment in the deterministic approach, using the ground motion parameters (acceleration, velocity, and displacement).
Scientific novelty and originality: The dispersion causes in relationship between different energy scales have been highlighted. The global to regional (Vrancea) released energy ratio and dynamics have been assessed. The source parameters of Vrancea area earthquakes were systematized and subsequently characterized. The focal mechanism and soil condition contribution on earthquake effects at the surface (case study: Cahul city area) have been assessted.
Important scientific problem solved consist of: detailed study of seismic source parameters and soil conditions (site effect) in the frame of their contribution on seismic effect on RM territory.
Theoretical value: The evolution of conceptual understanding of the „earthquake” phenomenon, by which were fitted the regional pecularities of research into the global study of earthquakes, has been shown. The source parameters comparative analysis highlighted the presence of the dispersion in mb values phenomenon, the seismic source directivity on energy release neglect and its consequences.
Practical value: The seismic source parameters catalogue and regional structure model developed facilitates the regional seismic hazard studies by statistic (probabilistic) and deterministic methods; the neo-deterministic method applyied for southern area of RM can be further extended to assesst the seismic hazard for whole RM territory in terms of dynamic ground movements; for the eastern area to East Carpathian, the constancy on S and P wave arrival time ratio has been established.
Implementation of the results: The results have been applied for Cahul city seismic zoning works. The microzoning map of Cahul city, developed with the author of the thesis, has been implemented in the RM Ministry of Construction and Regional Development system. The map in question was entered into force from July 01, 2014, according the order Nr.87 from May 30, 2014 of Minister of Construction and Regional Development.