BALTIC REGION: Seismicity Map and Composite Regional Catalog
(52-60N; 20-30E)
This region includes territories of Estonia, Latvia, Lithuania and Byelorussia. The region has a low seismicity, but studies have found 16 historical earthquakes. Seven earthquakes occurred in the recent/instrumental period; among them an Estonian earthquake with M=4.7. The detailed study of Byelorussia near Soligorsk ("Salt mountain")station, began in 1983. This station is located at approximately at 52.9N 27.8E.
At Soligorsk, instrumentation was installed in a mine, 600 m deep. The result supports the existence of seismicity here, connected with a fault system. During the years 1983-1986 it 146 small earthquakes were recorded, with energy class (K) from 6 to 9.5. For most of them, recorded by single station, no epicenter was estimated. All are in the vicinity of the Soligorsk. The S-P times vary from 2 to 5 sec; a very few events reach 8-10 of S-P time. Almost all these events are, therefore, located inside the area of 40-50 km radius around the Soligorsk; approximately 52.5-53.5N; 26.5-28E.
Some earthquakes are at distances sufficiently large that they do not originate from mining activity but are of "normal tectonic nature". Only one event coincides with the collapse of a mine roof. The calculated energy of rocks falling is about 100 times less than seismic energy of event. So the collapse could hardly have originated the observed seismic waves. It seems to be more probable that event in mine was a result of the earthquake.
While there are a lot of explosions in the region, the few known epicenters are shown on the map. They are located by western seismic surveys, especially Finnish. The clusters of epicenters are located at the places of active quarry blasting, especially along the Gulf of Finland. They have a classic “daytime” distribution. No any Russian survey processed and collect the data if recorded.