UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2024-11-23 18:01
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Conference: Bucharest University Faculty of Physics 2022 Meeting


Section: Atmosphere and Earth Science; Environment Protection


Title:
Improving location parameters for earthquakes in Romania using joint hypocenter determination method (JHD)


Authors:
Marius MIHAI(1,2), Mircea RADULIAN (1,2), Mihaela POPA (2), Bogdan GRECU(2)


*
Affiliation:
1)University of Bucharest, Faculty of Physics

2)National Institute for Earth Physics, Calugareni 12, Magurele, Ilfov, Romania


E-mail
nicu.mihai@infp.ro


Keywords:
seismicity, joint hypocenter determination method, earthquake catalog, ANTELOPE


Abstract:
The seismic activity in Romania is rather complex, with earthquakes occurring preferentially along Carpathians and in the adjacent areas. According to their specific properties, they can be included in different seismogenic zones, defined as areas with clustered seismicity where seismic activity and the orientation of the stress field are considered relatively uniform. The characterization of seismogenic processes and the assessment of seismic hazard are closely related to zonal seismicity. The determination of the specific characteristics of the seismogenic process is of particular importance for seismic hazard assessment and seismotectonics analysis. Scaling relationships of source parameters and local effects are directly related to seismic hazard prediction and assessment. Earthquake catalogues should provide an in-depth understanding of the seismotectonic setting of the areas of interest and are essential to develop a reliable seismic source model. For this study the data used are ANTELOPE routine and revised locations extracted from the INCDFP catalogue, which are furthermore relocated using joint hypocenter determination method (JHD). The basic idea behind this technique is to simultaneously determine an optimum 1-D structural model for the target area, to relocate the events and to fix a common set of station corrections. Under appropriate conditions, the station corrections reproduce the unmodeled velocity variations, and thus can significantly improve the location of events. These corrections are related to local effects characterizing the station site. The relocated earthquakes and quarry blasts using JHD better delimit specific clusters in comparison with routine catalog locations.