SEISMOLOGICAL OBSERVATION OF THE ROCKFALL ON RZENIK MOUNTAIN ON 26 FEBRUARY 2021, AND SOME OF ITS CHARACTERISTICS
Abstract
On 26 February 2021 at 6:16am a large rockfall occurred on Rzenik Mountain (1833 m) above the Kamniška Bela valley. This paper describes the seismological observations of this rockfall, which was not triggered by an earthquake, as well as morphometric and other characteristics. In addition, rockfalls in mountain areas frequently caused by strong earthquakes are briefly described. A comparison of aerial images taken before and after the Rzenik rockfall enabled a quantitative assessment of its extent. The break occurred in the west pillar of the north face, and was 200 m high and 100 m wide. The volume of the fallen rocks, deposited on the steep wooded slope across an area of 13 hectares, was estimated to be 625,000 m3 . The rockfall caused ground motion so strong that it was detected by most of the seismographs of the Slovenian seismological network, and also by two seismographs in Austria, at distances of 15 to 126 km. A comparison of the seismic records of this rockfall with a moderate tectonic earthquake of magnitude 1.8 and a large blast in a nearby quarry revealed a variety of different seismic waves and their generation. The 400 m high Rzenik wall is composed of Triassic limestone, and is known as one of the crumbliest in the Slovenian mountains. Geomorphologic analysis of a high resolution digital elevation model showed that large rockfalls have also occurred in this area in its geological history.
References
ARSO, 2020. Državna mreža potresnih opazovalnic je 28. februarja 2020 ob 10.32 zabeležila padec meteorita. https://twitter.com/ARSO_potresi/status/1233350684000620544 (6. julij 2023).
Babič, S., Golnar, T., 1987. Kamniške in Savinjske Alpe, Repov kot in Kamniška Bela, plezalni vodnik. Samozaložba, 112.
Bajc, J., Živčić, M., Gostinčar, M., 2004. Seizmična aktivnost v Šaleški dolini spomladi 2002. Potresi v letu 2002, 56–71. Ljubljana: Agencija RS za okolje.
Dammeier, F., Guilhem, A., Moore, J. R., Haslinger, F., Loew, S., 2015. Moment tensor analysis of rockslide seismic signals. Bulletin of the Seismological Society of America, 105, 3001–3014.
Deparis, J., Jongmans, D., Cotton, F., Baillet, L., Thouvenot, F., Hantz, D., 2008. Analysis of rock-fall and rock-fall avalanche seismograms in the French Alps. Bulletin of the Seismological Society of America 98, 1781–1796.
Frantar, P., Robič, M., 2009. Podori na območju slapa Čedca, Ujma, 23, 82–87.
Geološki zavod Slovenije 2023. Spletna aplikacija za popis in pregledovanje plazov in erozije. https://www.e-plaz.si/ (6. julij 2023).
Gosar, A., 2007. Letalsko lasersko skeniranje (LiDAR) Idrijskega in Ravenskega preloma v zahodni Sloveniji. Ujma 21, 139–144.
Gosar, A., 2012. Application of Environmental Seismic Intensity scale (ESI 2007) to Krn Mountains 1998 Mw = 5.6 earthquake (NW Slovenia) with emphasis on rockfalls. Nat. hazards earth syst. sci., 12/5, 1659–1670.
Gosar, A., 2014. Ocena intenzitet potresa leta 1998 v Krnskem pogorju z uporabo Environmental Seismic Intensity scale (ESI 2007). V Zorn in sod. (ur.): (Ne)prilagojeni. Naravne nesreče 3. GIAM ZRC SAZU, 83–93.
Guerrieri, L., Vittori, E., 2007. Intensity Scale ESI 2007. Memorie Descrittive della Carta Geologica D‘Italia, 74, 41.
Hrvatin, M., Komac, B., Perko, D., Zorn, M., 2006. Slovenia. In: Boardman., J., Poesen J. (Eds.) Soil erosion in Europe. 297–310, John Wiley & Sons.
Legradić, V., 2023. Grožnje gorskemu svetu – erozija v Alpah. Planinski vestnik, 123/2, 18–20.
Mrak, I., 2010. Uporaba metode datiranja površinske izpostavljenosti na primeru podora Veliki vrh. V: Zorn in sod. (ur). Od razumevanja do upravljanja. GI ZRC SAZU, Ljubljana.
Občina Kamnik 2021. Skalni podor v dolini Bele – na tem območju je priporočljiva skrajna previdnost. https://www.kamnik.si/objava/644034 6 (6. julij 2023).
Orožen Adamič, M., 1990. Podor v Trenti. Ujma, 4, 38-38.
Pahor, J., Zupančič, P., 2018: Preboj zvočnega zidu dveh letal na zapisih državne mreže potresnih opazovalnic. Potresi v Sloveniji 2016, 78–86. Ljubljana: Agencija RS za okolje.
Pavšek, M., 1994. Skalni podor v Trenti. Ujma, 8, 24–29.
PD Domžale 2021. Podor v Rzeniku iz zraka. https://www.pdd.si/2021/02/28/podor-v-rzeniku-iz-zraka/ (6. julij 2023).
Premru, U., 1982. Osnovna geološka karta SFRJ, list Ljubljana, 1 : 100.000. Geološki zavod Ljubljana.
Ribičič, M., Vidrih, R., 1999. Posledice potresa 1998 v naravi. Ujma, 13, 107–116.
Ribičič, M., 2014. Zemeljski plazovi – vrste in opis. Geološki zavod Slovenije, 32. https://www.e-plaz.si/Media/PDF/Priloga1_MRibicic_2014_ZEMELJSKI%20PLAZOVI%20(VRSTE%20IN%20OPIS).pdf (6. julij 2023).
Spurny, P., Borovička, J., Kac, J., Kalenda, P., Atanackov, J., Kladnik, G., Heinlein, D., Grau, T., 2010. Analysis of instrumental observations of the Jesenice meteorite fall on April 9, 2009. Meteoritics & planetary science. 45/8, 1392–1407.
Vidrih, R., Ribičič, M., 1998. Porušitve naravnega ravnotežja v hribinah ob potresu v Posočju 12. aprila 1998 in Evropska makroseizmična lestvica (EMS-98). Geologija, 41, 365–410.
Vidrih, R., Sinčič, P., Tasič, I., Gosar, A., Godec, M., Živčić, M., 2006. Državna mreža potresnih opazovalnic; Seismic network of Slovenia. Agencija RS za okolje, Urad za seizmologijo in geologijo, 287.
Vrhovec, T., 2003. Odmrzovanje permafrosta in podori v visokih alpskih stenah. Ujma, 17/18, 201–207.
Vrščaj, B., Bergant, J., Kastelic, P., Šinkovec, M., 2020. Erozija v Sloveniji. Ljubljana: Kmetijski inštitut Slovenije, 32.
Zorn, M., 2002a. Podori na Dobraču. Geografski vestnik, 74/2, 9–20.
Zorn, M., 2002b. Rockfalls in Slovene Alps. Geografski obzornik, XLII, 123–160.
Downloads
Published
Issue
Section
License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
The articles are made available to the public under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0).
