Scholarly record
FIRST MOTION FOCAL MECHANISM SOLUTION FOR VRANCEA ZONE - NEAR REAL TIME DETERMINATION
Abstract
Romanian seismicity, is characterized by a moderate rate of tectonic origin earthquakes, with an increase in density and higher magnitudes, within the Vrancea region, located at the South-Eastern Carpathians bend, at the conjunction of three major tectonic units: East European Plate, Intra-Alpine Plate and Moesian Plate. First-motion focal mechanism solutions are a good proxy for the initial rupture and they provide important additional information on the source mechanism. The data compiled in the present paper provides earthquake parameters for individual events of interest to contribute, as a valuable source of information, for further studies as seismotectonic investigations and stress distribution maps. We calculated the focal mechanisms using as a reference the phase pickings reported in the Romplus Catalogue, for intermediate depth earthquakes recorded in Vrancea region during 2015 – 2021. To determine fault planes solutions was implemented the FPFIT code [1] (code that generates parameters: strike, dip, rake, etc.) in ANTELOPE 5.6, software developed by Kinemetrics. This code (FPL) uses the classic criteria to determine the focal mechanisms, namely P wave polarities, systematic tests of all possible fault plane solutions, so will validate only those solutions who met the required criteria. Estimating the near-real-time fault planes solutions using dedicated programs, a few minutes after the event occurrence is done by generating locations of the seismic events with magnitude ML?3.5 for seismic events occurred at intermediate depths (H>60 km).
Publication Impact Profile
Publication details
References15
Reasenberg, P. and D. Oppenheimer, 1985. FPFIT, FPPLOT, and FPPAGE: FORTRAN computer programs for calculating and displaying earthquake fault-plane solutions. U.S Geol. Surv. Open-file rept. 85-739, 109pp.
Dziewonski, A.M., Chou, T.A., Woodhouse, J.H., Determination of earthquake source parameters from waveform data for studies of global and regional seismicity., 1981, Journal of Geophysical Research 86, 2825-2852.
Ekström, G., Dziewonski, A.M., Maternovskaya, N.N., Nettles, M., Global seismicity of 2002: centroid-moment-tensor solutions for 1034 earthquakes. 2005. Physics of the Earth and Planetary Interiors 148, 303–326.
Grimison, N.L., Chen, W.P. The Azores-Gibraltar plate boundary —focal mechanisms, depths of earthquakes, and their tectonic implications. 1986. Journal of Geophysical Research — Solid Earth and Planets 91 (B2), 2029–2047. http://dx.doi.org/ DOI: 10.1029/JB091iB02p02029.
Jackson, J., McKenzie, D. The relationship between plate motions and seismic moment tensors, and the rates of active deformation in the Mediterranean and Middle-East. 1988. Geophysical Journal International 93, 45–73.
Isacks, B., Molnar, P. Distribution of stresses in the descending lithosphere from a global survey of focal-mechanism solutions of mantle earthquakes. 1971. Reviews of Geophysics and Space Physics 9, 103–174.
Barba, S., Carafa, M., Mariucci, M.T., Montone, P., Pierdominici, S. Present-day stress-field modelling of southern Italy constrained by stress and GPS data. 2010. Tectonophysics 482, 193–204.
Gephart, J.W. Stress and the direction of slip on fault planes. 1990. Tectonics 9, 845–858.
Zoback, M.L. First- and second-order patterns of stress in the lithosphere: the World Stress Map project. 1992. Journal of Geophysical Research 97 (11), 703–711 (728).
Cinti, F.R., Faenza, L., Marzocchi, W., Montone, P. Probability map of the next M≥5.5 earthquakes in Italy. 2004. Geochemistry, Geophysics, Geosystems 5, Q11003. DOI: 10.1029/2004GC000724.
Scognamiglio, L., Tinti, E., Michelini, A. Fast determination of moment tensors and rupture history: what has been learned from the 6 April 2009 L'Aquila Earthquake sequence. 2010. Seismological Research Letters 81 (6), 892–906. http://dx.doi.org/ DOI: 10.1785/gssrl.81.6.892.
Craiu Andreea, Craiu Marius, Mihai Marius, Diaconescu Mihail, Ghita Cristian, Catalog of focal mechanisms for Vrancea (Romania) intermediate depth earthquakes (2005-2017), 17th International Multidisciplinary Scientific GeoConference SGEM. 2017.
Knapp, J.H., Diaconescu, C., Hauser, F., Prodehl, C., Raileanu, V., Matenco, L., Bala, A., Keller, G.R., Stephenson, R., Mocanu, V., Dinu, C., 2001. The Vrancea seismogenic zone, Romania: intermediate depth seismicity in search of a viable subduction zone. Eos, Transactions, American Geophysical Union 82 (47) (Fall Meet. Suppl.AbstractS42D-11).
Vamvakaris, D.A., Papazachos, C.B., Karagianni, E.E., Scordilis, E.M. and Chatzidimitriou P.M. Determination of faul plane solutions using waveform amplitudes and radiation pattern Geophysical Laboratory, School of Geology, Aristotle University of Thessaloniki, POBox 352-1 54124, Thessaloniki-GREECE, [email protected], Bulletin of the Geological Society of Greece, 2004, XXXVI (3):1529-1538, DOI: 10.12681/bgsg.16544.
Delvaux D., Sperner B.,2003. New aspects of tectonic stress inversion with reference to the TENSOR program. Geological Society London Special Publications 212(1):75-100 DOI: 10.1144/GSL.SP.2003.212.01.06.
View or Download full articleAccess options
SWS access login
Login as SWS Scientific CommitteeLogin as SWS Scientific PartnerLogin as SWS AuthorAuthors and approved SWS contributors will read and export their own linked papers after identity matching by SWS profile, email and SGEM GlobalID.
For librarian assistance: [email protected]
Purchase Instant Access
- Article can be downloaded after successful payment.
- Article may be used according to SWS library access terms.
- Article cannot be redistributed.
