At the Data and Analysis Centre of the National Network of Seismic Stations (NNSS) data from the seismic stations of national network and from seismic stations of cooperating institutions from Slovakia and abroad are collected and analysed in a real-time regime. In total, data from 55 seismic stations (so called the Regional Virtual Seismic Network of ESI SAS) are available real-time.
Data from the seismic stations of NNSS are provided real-time to all members of the Regional Virtual Seismic Network and to the international data centre ORFEUS in Netherlands. Some results of performed analyses are exchanged with various time delay as well.
Activities and analyses:
The Data and Analysis Centre performs preliminary automatic localizations of seismic events that are available real-time. Afterwards, the manual analysis is performed. During the manual analysis, arrival times of seismic waves are set for every identified seismic event. Manual localization is performed for chosen earthquakes, amplitudes and periods of appropriate seismic waves are estimated and magnitudes computed as well.
The Data and Analysis Centre takes part in a standard international data exchange. So called “seismo reports” (arrival times of identified seismic waves, amplitudes and periods of chosen seismic waves, magnitudes and epicentral distances for recorded earthquakes) are regularly sent to the cooperating institutions and international seismological centres twice per week. Based on this information, earthquakes are re-localized at the international centres. The new and more precise localizations are then published at their web pages and are sent back to national data centres. After that, earthquakes’ recordings are re-analysed at the national data centres (including our data centre) and adjusted data are sent to the main international data centre “International Seismological Centre” (ISC, United Kingdom) in the form of so called “monthly bulletins”. Having this kind of information processed, the ISC issues “monthly ISC bulletin” that is composed of data and final localizations of world-wide recorded earthquakes.
Besides seismometric data, macroseismic data are collected and processed in the data centre too. Macroseismic data characterize effects of an earthquake on people, objects, buildings and nature. In a case of an earthquake with macroseismic effects on the territory of Slovakia, the ESI SAS collects macroseismic observations of the earthquake. These observations are collected through internet, e-mail or mail. In such a case, the ESI SAS publishes a special announcement at the web page www.seismology.sk (www.zemetrasenia.sk) that keeps public informed about the earthquake (origin time, epicentre, map with places of observations). Data from the macroseismic questionnaires and possible additional data (e.g. from field inspections) are evaluated using the 12 degrees macroseismic scale EMS-98. A macroseismic intensity is estimated for each location with macroseismic observations available.
Results of analyses performed in the Data and Analysis Centre of NNSS enters into the cumulative national seismic database for the territory of Slovakia that has been long created at the ESI SAS (former Geophysical Institute SAS)
Hardware and software equipment:
- a server for real-time data acquisition from the seismic stations of NNSS
- a disk array for archiving of seismic records in the miniSEED format
- a server for real-time data acquisition from the seismic stations of cooperating institutions from Slovakia and abroad. This server also provides data from the seismic stations of NNSS to the cooperating institutions and performs an automatic processing and preliminary location of seismic events.
- an analysis computer for manual processing and analyses of data from the seismic stations of NNSS and the Regional Virtual Seismic Network of ESI SAS
- a web server for the web pages seismology.sk and www.zemetrasenia.sk
In order to keep the data centre in operation even in situations of power or internet connection failure, the data centre is equipped with a power generator and satellite data acquisition from selected seismic stations of the NNSS. The data acquisition servers, the web server and the archiving disk array are located in a separate room with air-conditioning.
- a software package SeisComp3 for real-time data acquisition and preliminary automatic analysis a software package SeismicHandler with a localization software LocSat for manual processing, analyses and localization of seismic events