Idrija Fault

The Idrija Fault (pronounced [ˈiːdrija]; Slovene: Idrijski prelom) is a seismically active fault in Slovenia.^[1][2] It strikes NW–SE and the fault plane dips towards the northeast. The activity along the fault started in the Miocene with normal faulting and changed to dextral strike-slip in the Pliocene. The fault was first described by the Slovene geologist Marko Vincenc Lipold.^[3][4] The present displacement is measured and varies along strike but is in the order of magnitude of 0.1 mm per year.^[3]

The strongest earthquake that possibly happened along the Idrija Fault was the 1511 Idrija earthquake, which took place on 26 March 1511. It had a moment magnitude of 6.9 and achieved a maximum intensity of X ("very destructive") as per the EMS scale. It caused 3,000 deaths and extensive damage.^[5][6] In the 20th century, the fault caused the Cerknica Earthquake in 1926 and the Upper Soča Valley Earthquake [sl] in 1998 (both EMS VII–VIII).^[7]