Idrija Fault Explained

The Idrija Fault (in Slovenian pronounced as /ˈiːdrija/; Slovenian: 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.

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 material damage.^{[5] [6]} In the 20th century, the fault caused the Cerknica Earthquake in 1926 and the in 1998 (both EMS VII–VIII).^[7]

Notes and References

1. Poljak. Marijan. Gosar. Andrej. Živčić. Mladen. ActivetectonicsinSlovenia. GeoActa. 2010. Special Publication 3. 10 August 2014.
2. Book: Nicholas . Pinter. The Adria microplate : GPS geodesy, tectonics and hazards : [proceedings of the NATO Advanced Research Workshop on the Adria Microplate: GPS Geodesy, Tectonics and Hazards, Veszprem, Hungary, April 4-7, 2004]. 2006. Springer. Dordrecht. 978-1-4020-4233-1.
3. Bavec. Milos. Car. Marjeta. Stopar. Robert. Jamsek. Petra. Gosar. Andrej. Geophysical evidence of recent activity of the Idrija fault, Kanomlja, NW Slovenia. Materials and Geoenvironment. 2012. 59.
4. Lipold. Marc Vincenc. Bericht über die geologischen Aufnamen in Ober-Krein im Jahre 1856. Jahrbuch der k. k. geol. Reichsanstalt. 1857.
5. Web site: Potresi in nova karta potresne nevarnosti Slovenije . sl . Earthquakes and a new Earthquake Hazard Map of Slovenia . Geological Survey of Slovenia . 23 April 2024.
6. Idrijski potres 26. marca 2011 . Cecič . Ina . sl . The 26 March 1511 Earthquake – What Do We Know About It? . Geografski obzornik [Geographic Horizon] . 1 . 58 . 2011 . 0016-7274 . Association of Slovenian Geographers.
7. Fitzko. F.. Suhadolc. P.. Aoudia. A.. Panza. G.F.. Constraints on the location and mechanism of the 1511 Western-Slovenia earthquake from active tectonics and modeling of macroseismic data. Tectonophysics. 404. 1-2. 77–90. 10.1016/j.tecto.2005.05.003.