Zjawiska sejsmiczne w rejonie kopalni węgla brunatnego Bełchatów
Abstract
SEISMIC PHENOMENA I N THE REGION OF BEŁCHATÓW BROWN COAL MINE
Summary
The data on tremors which are occurring in the area of brown coal open-cast mine Bełchatów (Fig. 1) after some progress in mining works has been achieved, are summarized (Tables I and Il, Figs 2-4). Three geological hypotheses are analysed:
1) a shallow (about 500 m deep) source from disloading;
2) source in zone of occurrence of Zechstein salts (at depth of 3-4 km, Fig. 5), related to their creep; and
3) deep-seated (at depth of about 5 km) source, related to ancient fracture zone in Permian basement.
The drop in stress related to the recorded tremors is several times greater than that of stresses related to mining works, which seem to support the hypotheses 2) and 3). It seems that the tremors should recur, resulting in seismic hazard on a regional scale.
Summary
The data on tremors which are occurring in the area of brown coal open-cast mine Bełchatów (Fig. 1) after some progress in mining works has been achieved, are summarized (Tables I and Il, Figs 2-4). Three geological hypotheses are analysed:
1) a shallow (about 500 m deep) source from disloading;
2) source in zone of occurrence of Zechstein salts (at depth of 3-4 km, Fig. 5), related to their creep; and
3) deep-seated (at depth of about 5 km) source, related to ancient fracture zone in Permian basement.
The drop in stress related to the recorded tremors is several times greater than that of stresses related to mining works, which seem to support the hypotheses 2) and 3). It seems that the tremors should recur, resulting in seismic hazard on a regional scale.