Data processing of natural and induced events recorded at the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC)

The operation of the seismic station Ostrava-Kr¨¢sn¨¦ Pole (OKC) (¦Õ = 49.8352¡ãN; ¦Ë = 18.1422¡ãE) which is situated at present in an experimental gallery nearby the Ostrava planetarium started in the year 1983 being equiped initially by analogue instrumentation. Modernization of instrumentation at the station was aimed at the installation of a new digital data acquisition system and the respective software packages for data interpretation and transmission.Data acquisition system VISTEC is based on PC which enables continuous recording of three- component short-period and medium-period systems with the sampling frequency of 20 Hz. The basic advantage of the OS Linux adopted allows remote access (telnet) and the possibility of the recorded data transmission (ftp). Possible troubles in the seismic station operation can be quickly detected (even automatically) and all recorded data are with minimum delay on disposal. The use of the remote access makes possible also to change the parameters of measuring set-up. The standard form of output data allows the application of standard software packages for visualisation and evaluation. There are on disposal following formates: GSE2/CM6, GSE2/INT and MiniSEED. The output data sets can be compressed by a special procedure. For interactive interpretation od digital seismic data, software package EVENT developed in the Geophysical Institute AS CR and package WAVE developed in the Institute of Geonics AS CR are used.Experimental operation of digital seismographs at the station OKC confirmed justification of its incorporation into the seismic stations of the Czech national seismological network (CNSN). Based on the preliminary analysis of digital data it proved that following groups of seismic events are recorded: earthquakes, induced seismic events from Polish copper and coal mines, induced seismic events from the Ostrava-Karvin¨¢ Coal Basin, quarry blasts and weak regional seismic events of the tectonic nature.Daily direct access to the digital data and their transmission via Internet makes it possible continuous evaluation and storage of seismic activity recorded in the frame of the CNSN and also the incorporation of interpreted data into the seismic bulletins prepared in the computer centre of the Geophysical Institute AS CR in Prague