Next Article in Journal
Thermal Conductivity of Frozen Sediments Containing Self-Preserved Pore Gas Hydrates at Atmospheric Pressure: An Experimental Study
Next Article in Special Issue
Modelling of a Large Landslide Problem under Water Level Fluctuation—Model Calibration and Verification
Previous Article in Journal / Special Issue
An Experimental Investigation on the Progressive Failure of Unsaturated Granular Slopes
Open AccessArticle

Impact of a Random Sequence of Debris Flows on Torrential Fan Formation

Faculty of Civil and Geodetic Engineering, University of Ljubljana, 1000 Ljubljana, Slovenia
Author to whom correspondence should be addressed.
Geosciences 2019, 9(2), 64;
Received: 20 November 2018 / Revised: 17 January 2019 / Accepted: 21 January 2019 / Published: 29 January 2019
(This article belongs to the Special Issue Mountain Landslides: Monitoring, Modeling, and Mitigation)
PDF [13072 KB, uploaded 29 January 2019]


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 m3 to 20,000 m3 were selected, and the total volume was approximately 225,000 m3. 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. View Full-Text
Keywords: debris fans; RAMMS; numerical modelling; debris flow sequence; hazard assessment; Suhelj fan debris fans; RAMMS; numerical modelling; debris flow sequence; hazard assessment; Suhelj fan

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Share & Cite This Article

MDPI and ACS Style

Bezak, N.; Sodnik, J.; Mikoš, M. Impact of a Random Sequence of Debris Flows on Torrential Fan Formation. Geosciences 2019, 9, 64.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Geosciences EISSN 2076-3263 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top