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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:29 |
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Conference: Bucharest University Faculty of Physics 2015 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Lithosphere structure around Bucovina seismic array (Romania) from Vp /Vs ratios and travel times curves revealed by crustal seismic events
Authors:
Daniel STOICESCU(1), Felix. BORLEANU(2), L. MANEA(2)
Affiliation:
1) University of Bucharest, Faculty of Physics, P.O.BOX MG-11, Magurele, Bucharest, Romania
2) National Institute for Earth Physics, Magurele, Romania
E-mail
daniel.stoicescu18@gmail.com
Keywords:
seismic activity,BURAR array,Vp/Vs ratios
Abstract:
Generally the NE part of Romania is characterized by low seismic activity. The seismic events of small – to - moderate magnitude are occurring mainly in the upper crust. During the last decade, local seismicity monitoring has improved substantially as a result of National Seismic Networks upgrades, making it possible to decrease the threshold detectability of seismic events and consequently increase location performances. We selected a region of 1x1o around the Bucovina (BURAR) seismic array in order to investigate lithosphere structure and improve location accuracy. The BURAR array is located in the northeastern part of the country near the Ukraine, border. Since its installation in 2002, the array provides the higher quality recordings, the seismic sensors being installed in boreholes at 30m depth. In this respect the array is widely used in location purposes being necessary to have as accurately as possible knowledge regarding the local structure. For this purpose we selected crustal events occurred in the last decade within this region. For each event we verified the location accuracy through the Wadati diagram plot and computed Vp/Vs ratios. The travel time curves were represented for regional phases considering all the selected events. Preliminary results show that the variation of Vp / Vs ratios are in range of 1.69 - 1.80, and the mean Moho discontinuity depth varies between 30 and 40 km depending on azimuth. The results were compared with existing geophysical models and the stability was verified applying different statistical methods.
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