15:30 〜 16:30
[S01-P-19] The seismic sequence of the magnitude 5.7 crustal earthquake of 2014 of Focsani Basin (Romania) – relevant data regarding the stress field in front of the Southeastern Carpathians bend
The seismic sequence of the crustal earthquake which occurred on November 22, 2014 in Focsani Basin is the strongest seismic energy release in front of the Southeastern Carpathians bend since 1900. The main shock with local magnitude 5.7 is the largest instrumentally recorded event in the region. Its aftershock sequence lasted about 70 days, more than 250 earthquakes with local magnitude > 0.1 were localized using the records collected by the Romanian seismic network.
The sequence occurred in the lower crust – the depth of the main shock was 40 km and the majority of the aftershocks had depths greater than 25 km – in the Focsani Basin (part of the Moesian Platform), nearby the contact point of three important tectonic units: the Scythian Platform, the Moesian Platform and the North Dobrogea Promontory. The epicenter distribution – along a NNE-SSW direction – follows the orientation of the Carpathian arc.
We present the detailed space-time evolution of the seismic energy release and determine the focal mechanism of the largest shocks, for which reliable P-wave polarity data are available – 11 events with local magnitude > 2.5.
The fault plane solution of the mainshock shows normal faulting with a dominant dip-slip component; the nodal planes are oriented SE-NW. Similar mechanisms are obtained for the strongest aftershocks – 2 events with local magnitudes above 4. Although a certain variability of the fault plane solutions of the weaker events is observed, the normal faulting dominates among the retrieved focal mechanisms.
The sequence occurred in the lower crust – the depth of the main shock was 40 km and the majority of the aftershocks had depths greater than 25 km – in the Focsani Basin (part of the Moesian Platform), nearby the contact point of three important tectonic units: the Scythian Platform, the Moesian Platform and the North Dobrogea Promontory. The epicenter distribution – along a NNE-SSW direction – follows the orientation of the Carpathian arc.
We present the detailed space-time evolution of the seismic energy release and determine the focal mechanism of the largest shocks, for which reliable P-wave polarity data are available – 11 events with local magnitude > 2.5.
The fault plane solution of the mainshock shows normal faulting with a dominant dip-slip component; the nodal planes are oriented SE-NW. Similar mechanisms are obtained for the strongest aftershocks – 2 events with local magnitudes above 4. Although a certain variability of the fault plane solutions of the weaker events is observed, the normal faulting dominates among the retrieved focal mechanisms.