Properties of the 1979 Monte Negro (southwest Yugoslavia) seismic sequence

Focal properties of the Monte Negro earthquake (15 April 1979,M=7.1) and its seismic sequence (foreshocks and aftershocks), which occurred near the southwestern coast of Yugoslavia, are investigated. Fault plane solutions of the main shock and its largest aftershock (24 May 1979,M=6.3) and the spatial distribution of the shocks of this sequence show that the seismic fault strikes about southeast-northwest (parallel to the coast) and dips northeast (towards the continent). It is a strike-slip left-lateral fault with a considerable thrust component. Its length is 95 km and its width 12 km. An aseismic belt, which separated the aftershock foci into two groups (the northwestern and southeastern), is interpreted as a section of the fault that slipped smoothly during the main shock. The aftershock foci were barriers where stress had been induced. One of these barriers broke later and produced the largest aftershock of 24 May.