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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:25 |
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Conference: Bucharest University Faculty of Physics 2006 Meeting
Section: Atmosphere and Earth Science; Environment Protection
Title:
Earthquake warning using P-wave amplitudes recorded in Vrancea epicentral area. Preliminary study.
Authors:
Daniel Paulescu, Constantin Ionescu, Bogdan Grecu, Mihaela Popa, Mircea Radulian
Affiliation:
National Institute for Earth Physics, 12 Calugareni St., 077125, PO Box MG-2 Magurele, Romania
E-mail
Keywords:
seismotectonics, P-wave,crustal earthquakes
Abstract:
The Bucharest metropolitan area is one of the most vulnerable urban areas in the world due to Vrancea earthquakes. Although situated relatively far away (150-170 km) from the Vrancea seismic source, Bucharest suffered a lot of damage following the strong Vrancea earthquakes (e.g. November 10th 1940 Mw = 7.7 and March 4th 1977 Mw = 7.4 events). The particular Vrancea seismotectonics and geometrical source-site features made possible the conception of a rapid seismic warning system for Bucharest area (Wenzel et al., 1999). The system is simple, reasonably low-priced and robust and allows warning in an approximately 25 second time window for Bucharest. The purpose of our study is to use the amplitude of the P-wave arrivals recorded at 2 epicentral stations (Vrancioaia - VRI, Plostina - PLOR) for a rapid estimation of the expected earthquake magnitude and of the associated hazard. In order to set the calibrations, we use 52 earthquakes with a moment magnitude between 4 and 6 occurred between 1996 – 2004 at an interval depth of 70-166 km. The maximum amplitude is measured for two successive time windows of 1-2 s and 3-4 s, selected after the P-wave onset. Finally, we estimate the calibration relationships between the maximum amplitude and magnitude taking also into account the depth intervals of the earthquakes. Our preliminary results will be further on tested for an extended data set of intermediate-depth and crustal earthquakes.
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