Natural Hazards and Earth System Science www.nat-hazards-earth-syst-sci.net 1561-8633 1684-9981 8 1 2008 10.5194/nhess-8-59-2008 http://www.nat-hazards-earth-syst-sci.net/8/59/2008/ http://www.nat-hazards-earth-syst-sci.net/8/59/2008/nhess-8-59-2008.html http://www.nat-hazards-earth-syst-sci.net/8/59/2008/nhess-8-59-2008.pdf 59 66 2008-02-08 Static stress changes due to the 1998 and 2004 Krn Mountain (Slovenia) earthquakes and implications for future seismicity A. Ganas aganas@gein.noa.gr A. Gosar G. Drakatos Geodynamics Institute, National Observatory of Athens, Lofos Nymfon, 118 10 Athens, Greece Environmental Agency of the Republic of Slovenia, Seismology and Geology Office Dunajska 47, 1000 Ljubljana, Slovenia In this paper we examine the Coulomb (static) stress pattern following the two moderate magnitude earthquakes in NW Slovenia during 1998 and 2004. These earthquakes ruptured patches of the NW-SE striking Ravne fault that crosses the Krn Mountain. The objective is to investigate the seismicity patterns for this area of Slovenia given that future earthquakes may be triggered as a result of stress changes along neighbouring faults. Our findings include: a) stress levels have increased along the active Ravne fault for all models discussed b) stress levels have decreased along the active, NW-SE striking Idrija fault and c) stress levels throughout the crust have increased along the E-W direction but have decreased in the N-S direction (stress shadow effect). We also mapped a better correlation of the off-fault aftershock locations with stress maps incorporating the regional stress field. Aoudia, A., Zille, A., Borghi, A., Riva, R., Barzaghi, R., Živčić, M., and Panza, G.: The July 2004 Western Slovenia earthquake: From localised fault-scale complexities to distributed deformation at the junction between the south-eastern Alps and External Dinarides, Geophys. Res. Abstr., 7, 09258, 2005. 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