Impact of a random sequence of debris flows on torrential fan formation

Bezak, Nejc (avtor), Sodnik, Jošt (avtor), Mikoš, Matjaž (avtor)

Debris flows with different magnitudes can have a large impact on debris fan characteristics such as height or slope. Moreover, knowledge about the impact of random sequences of debris flows of different magnitudes on debris fan properties is sparse in the literature and can be improved using numerical simulations of debris fan formation. Therefore, in this paper we present the results of numerical simulations wherein we investigated the impact of a random sequence of debris flows on torrential fan formation, where the total volume of transported debris was kept constant, but different rheological properties were used. Overall, 62 debris flow events with different magnitudes from 100 m$^3$ to 20,000 m$^3$ were selected, and the total volume was approximately 225,000 m$^3$. The sequence of these debris flows was randomly generated, and selected debris fan characteristics after the 62 events were compared. For modeling purposes, we applied the Rapid Mass Movement Simulations (RAMMS) software and its debris flow module (RAMMS-DF). The modeling was carried out using (a) real fan topography from an alpine environment (i.e., an actual debris fan in north-west (NW) Slovenia formed by the Suhelj torrent) and (b) an artificial surface with a constant slope. Several RAMMS model parameters were tested. The simulation results confirm that the random sequence of debris flow events has only some minor effects on the fan formation (e.g., slope, maximum height), even when changing debris flow rheological properties in a wide range. After the 62 events, independent of the selected sequence of debris flows, the final fan characteristics were not significantly different from each other. Mann Whitney (MW) tests and t-tests were used for this purpose, and the selected significance level was 0.05. Moreover, this conclusion applies for artificial and real terrain and for a wide range of tested RAMMS model rheological parameters. Further testing of the RAMMS-DF model in real situations is proposed in order to better understand its applicability and limitations under real conditions for debris flow hazard assessment or the planning of mitigation measures.

• Jezik: Angleški jezik
• Ključne besede: debris fans, RAMMS, numerical modelling, debris flow sequence, hazard assessment, Suhelj fan
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FGG - Fakulteta za gradbeništvo in geodezijo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2019
• Št. strani: 14 str.
• Številčenje: Vol. 9, iss. 2, art. 64
• PID: 20.500.12556/RUL-131996
• UDK: 556:004(479.4)
• ISSN pri članku: 2076-3263
• DOI: 10.3390/geosciences9020064
• COBISS.SI-ID: 8679265
• Datum objave v RUL: 08.10.2021

Gradivo je del revije

• Naslov: Geosciences
• Skrajšan naslov: Geosciences
• Založnik: MDPI
• ISSN: 2076-3263
• COBISS.SI-ID: 519967769

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.
• Začetek licenciranja: 01.02.2019

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: vršaj, RAMMS, numerično modeliranje, zaporedje drobirskih tokov, ocena ogroženosti, Suhelj, hidrologija

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: J7-8273
• Naslov: Prepoznavanje potencialno nevarnih hudourniških vršajev z metodami geomorfometrije in simulacijami nastanka vršajev

• Financer: Drugi - Drug financer ali več financerjev
• Program financ.: International Programme on Landslides
• Številka projekta: IPL-225