Efficiency of the Seismological Network of the Republic of Karelia

To solve many geological and geophysical problems, in particular, prediction of strong earthquakes, seismic zoning, and earthquake-resistant construction, it is necessary to have reliable data on the distribution of earthquake hypocenters in the study area. In turn, the completeness of data on the distribution of earthquake hypocenters and accuracy of their determination largely depend on the efficiency of the observation system. We evaluate the efficiency of the actual network of seismological observations in Karelia, which consists of seven seismic stations. The efficiency of the seismological observation network is estimated by the minimum magnitudes of seismic events recorded in the considered region and the minimum errors in determining the main parameters (origin time and hypocentral coordinates) of the recorded events. Calculation of the minimum earthquake magnitudes for the Karelian seismological network shows that a station amplification of 30 000, the network is able to record earthquakes with a magnitude slightly less than 2, with a tendency towards a decrease in this minimum magnitude, provided that the event is recorded by at least three stations. The errors in determining earthquake epicentral coordinates in latitude δφ (km) and longitude δλ (km) do not exceed 1–2 km in the center of the network, and 6 and 11 km on the periphery, respectively. The system’s errors in determining the depths of earthquake sources H (km) do not exceed 5 km in the vicinity of the stations and 25 km throughout the territory of Karelia.