The space and time pattern of the local seismicity in Slovenia

Abstract

The territory of Slovenia is subdivided into five seismogenetic regions according to their geological, tectonical, and geophysical properties. The seismicity of these regions is determined on the basis of more than 3000 earthquakes contained in the catalogue for Slovenia . Seismically most active part is concentrated in central, south-eastern and south-western Slovenia (zones B 2 , B 3 , and A 2 ).

Temporal energy release, strain release and indexes of seismic activity Ā₁₀ have been determined for all characteristic regions. Introducing parameter = E^2/3 it is shown that a temporal dependence of the activity exists, and further, that and increase of the activity in south-eastern and south-western Slovenia is accompanied by a decrease of activity in its central part, and vice versa.

Variations of b -value in the relation logN=a - bM have been determined for the three characteristic regions A 2 , B 2 , and B 3 . They have been correlated with times of occurrence of strong earthquakes. It is shown that most events occurred in time intervals when the b -value was 0.9 or less, or when the trend of the b -value was negative.