Effects of the process within the earthquake focus upon the seismic zoning of the terrain.

(in Croatian)

Abstract

Analysis of microseismic and macroseismic data of some earthquakes in our country and comparison with the tectonic characteristics of region points to the conclusion that the fault in the earthquake focus could not always be presented by motion on one plain only.

From those empirical data we also learn the kind of motion in the focus that affects the character of the seismic ground oscillation, as well as the character and intensity degree. Thus, in seismic zoning, besides all other elements which are usually taken into consideration, it is also necessary to consider the following: orientation and dimension of the focus, and the kind and size of the motion in it. Then the spatial relationship between the motion focus and the area on the surface of the Earth under consideration could be determined, along with the dynamic characteristics of the seismic oscillations, and also the volume of the released energy, as well as the intensity degree of expected motion in future, which, as it can be seen from some examples, can reach almost the same maximal epicentral value not only in the epicentral area but also outside it.