Real time performance of the Mw estimation for vrancea intermediate depth earthquakes recorded by the accelerometers of the national seismic network

The seismicity of Romania is significantly affected by earthquakes produced by the Vrancea seismic source with intermediate depth events (3 shocks/century with magnitude Mw greater than 7.0). The seismic activity on the Romanian territory consists of both shallow and intermediate-depth earthquakes. The crustal seismicity is moderate and more scattered in comparison with the intermediate-depth one. The recent upgrade of the seismic network in Romania with high dynamic range accelerometers ( 114 real time seismic stations equipped with episensors) allows recording of moderate to large magnitude earthquakes at very close epicentral distances (less than 10-20 km). Strong motion data of high quality are also of help in increasing the effective preparation against seismic disasters, and the response during seismic emergencies. The consequent increased ability of a community to quickly recover from the damages of an earthquake thus contributes to lower the seismic risk, usually measured in term of casualties and economic losses. During 2016 in this seismic area were recorded two moderate events with 5.7 magnitude in September respectively December. The purpose of this work consists mainly in the estimation of moment magnitude Mw using the strong motion network of the NIEP. A stable and automatic method was developed by Gallo et al.,2014, has been implemented in the real time data acquisition and processing system (ANTELOPE) to estimate in real time the seismic moment, the moment magnitude and the corner frequency of events recorded by accelerometers, using Andrews (1986) method applied to S waves. The main goals are the independent estimation of seismic moment and the common characterization for all events recorded by the strong motion network.