Dynamics of Rockslides and Rockfalls

Erismann, Theodor H.; Abele, Gerhard

doi:10.1007/978-3-662-04639-5

Cited by 211 publications

(217 citation statements)

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“…The mobilized material moved down the several hundred meters high rock cliff as a more or less freefalling particle cloud (Erismann and Abele, 2001). A secondary rockfall event can thus be defined as a short-term mass deposition of fine-grained rockfall material that originates from intermediate storages in the rock wall and is re- Fig.…”

Section: Discussionmentioning

confidence: 99%

A nonlinear model coupling rockfall and rainfall intensity based on a four year measurement in a high Alpine rock wall (Reintal, German Alps)

Krautblatter

Möser

2009

Nat. Hazards Earth Syst. Sci.

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Abstract.A total of more than 140 000 kg of smallmagnitude rockfall deposits was measured in eight rockfall collectors of altogether 940 m 2 in size between 1999-2003 below a 400-600 m high rock face in the Reintal, German Alps. Measurements were conducted with a temporal resolution up to single days to attribute rockfall intensity to observed triggering events. Precipitation was assessed by a rain gauge and high-resolution precipitation radar. Intense rainstorms triggered previously unreported rockfall intensities of up to 300 000 g/(m 2 h) that we term "secondary rockfall event." In comparison to dry periods without frost (10 −2 g/(m 2 h)), rockfall deposition increased by 2-218 times during wet freeze-thaw cycles and by 56-thousand to 40-million times during secondary rockfall events. We obtained three nonlinear logistic growth models that relate rockfall intensity [g/(m 2 h)] to rainfall intensity [mm/h]. The models account for different rock wall intermediate storage volumes, triggering thresholds and storage depletion. They apply to all rockfall collector positions with correlations from R 2 =0.89 to 0.99. Thus, the timing of more than 90% of the encountered rockfall is explained by the triggering factor rainfall intensity. A combination of rockfall response models with radar-supported storm cell forecast could be used to anticipate hazardous rockfall events, and help to reduce the exposure of individuals and mobile structures (e.g. cable cars) to the hazard. According to meteorological recordings, the frequency of these intense rockfall events is likely to increase in response to global warming.

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Section: Discussionmentioning

confidence: 99%

A nonlinear model coupling rockfall and rainfall intensity based on a four year measurement in a high Alpine rock wall (Reintal, German Alps)

Krautblatter

Möser

2009

Nat. Hazards Earth Syst. Sci.

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“…In large parts of the Alps and other mountainous regions, rockfall is a major threat to settlements and transportation routes (Varnes, 1978;Hutchinson, 1988;Flageollet and Weber, 1996;Hungr et al, 1999;Erismann and Abele, 2001;Budetta, 2004). As a consequence, measures have to be taken for public protection.…”

Section: Introductionmentioning

confidence: 99%

Spatial and temporal rockfall activity in a forest stand in the Swiss Prealps—A dendrogeomorphological case study

2006

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Rockfall is a major threat to settlements and transportation routes in large parts of the Alps. While protective forest stands in many locations undoubtedly reduce rockfall risk, little is known about the exact frequency and spatial distribution of rockfall activity in a given place or about how these parameters can be assessed. Therefore, the objective of the present study was to reconstruct rockfall events with dendrogeomorphological methods and to analyse the spatial and temporal rockfall activity in a subalpine forest stand. The study site is located in the transit zone of frequently passing, rather small rockfall fragments (mean diameter of 10 to 20 cm). In all, 33 stem discs from previously felled Picea abies trees found at the foot of Schwarzenberg in Diemtigtal (Swiss Prealps) were sampled, and a total number of 301 rockfall events were dated to between A.D. 1724 and 2002.Results showed that the spatial distribution of rockfall changed slightly with time, and that rockfall activity increased considerably over the last century. In contrast, rockfall magnitude presumably remained on a comparable level. The seasonal occurrence of rockfall showed a clear peak during the dormant season of trees, most probably in early spring. Furthermore, on a 10-year moving average basis, rockfall rates were positively correlated with mean annual as well as summer and winter temperatures. This means that higher temperatures resulted in increased rockfall activity. On the other hand, no correlation with annual or seasonal precipitation totals was revealed. Overall, this study provides an appropriate method for the detailed assessment of spatial and temporal variations in rockfall activity in a given place.

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“…Well-known examples are rockfall, defined in this paper as the fall of single rocks and stones with a volume smaller than 5 m 3 (Jahn, 1988;Gsteiger, 1993;Erismann and Abele, 2001;Berger et al, 2002), and snow avalanches (Berger, 1996;Weir, 2002). Without these forests, the costs of building and maintaining technical protective constructions would be unaffordable.…”

Section: Introductionmentioning

confidence: 99%

Real-size experiments and 3-D simulation of rockfall on forested and non-forested slopes

Dorren

Berger²,

Putters³

2006

Nat. Hazards Earth Syst. Sci.

187

119

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Abstract. Only a few rockfall simulation models take into account the mitigating effect of existing forest cover. The objective of our study was to improve the generic rockfall simulation model RockyFor, which does take the effect of forest stands into account, thereby developing a clear method for quantifying and modelling slope surface characteristics based on quantitative field data. To obtain these data we carried out 218 real-size rockfall experiments on forested and non-forested sites on a mountain slope in the French Alps. On the basis of a polygon map representing different diameter classes of the material covering the slope, we determine the mean obstacle height (MOH) for each homogeneous unit at the experimental sites. We proposed an algorithm for calculating the tangential coefficient of restitution using the MOH. Comparing the simulated and observed data from the real-size rockfall experiments showed that the 3-D combined deterministic-probabilistic rockfall simulation model RockyFor accurately predicted rockfall events on a non-forested (Root Mean Square Error = 17%) and a forested site (Root Mean Square Error = 12%). We conclude that for further improvement of rockfall-forest simulation on different slope types more quantitative data is required on (1) the energy dissipative capacity of shrubs and bushes (e.g. in coppice stands), (2) the effect of the slope material, (3) the rock shape as well as the rock size, and (4) the tangential and normal coefficient of restitution. Based on the presented results we can state that the RockyFor model could contribute to better taking into account the mitigating effect of the existing forest cover when planning protective measures.

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Dynamics of Rockslides and Rockfalls

Abstract: Dynamics of rockslides and rockfalls I Theodor H. Erismann, Gerhard Abele. p.cm. Includes bibliographical references and index.

Cited by 211 publications

References 0 publications

A nonlinear model coupling rockfall and rainfall intensity based on a four year measurement in a high Alpine rock wall (Reintal, German Alps)

A nonlinear model coupling rockfall and rainfall intensity based on a four year measurement in a high Alpine rock wall (Reintal, German Alps)

Spatial and temporal rockfall activity in a forest stand in the Swiss Prealps—A dendrogeomorphological case study

Real-size experiments and 3-D simulation of rockfall on forested and non-forested slopes

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