scholarly journals Definitions and Concepts for Quantitative Rockfall Hazard and Risk Analysis

Geosciences ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 158
Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests using terms that appear to be the most logic and explicit as possible and describes methods to derive some of the main hazards and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized and diffuse hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed, and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the reach probability, and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (passage frequency) can be derived. This frequency is relevant for risk assessment when the element at risk can be damaged several times. If it is not replaced, the probability that it is impacted by at least one rockfall is more relevant.

Author(s):  
Didier Hantz ◽  
Jordi Corominas ◽  
Giovanni B. Crosta ◽  
Michel Jaboyedoff

There is an increasing need for quantitative rockfall hazard and risk assessment that requires a precise definition of the terms and concepts used for this particular type of landslide. This paper suggests to use terms that appear to be the more logic and explicit as possible, and describes methods to derive some of the main hazard and risk descriptors. The terms and concepts presented concern the rockfall process (failure, propagation, fragmentation, modelling) and the hazard and risk descriptors, distinguishing the cases of localized hazards and diffused hazards. For a localized hazard, the failure probability of the considered rock compartment in a given period of time has to be assessed and the probability for a given element at risk to be impacted with a given energy must be derived combining the failure probability, the propagation probability and the exposure of the element. For a diffuse hazard that is characterized by a failure frequency, the number of rockfalls reaching the element at risk per unit of time and with a given energy (reach frequency) can be derived. However, when the element at risk is not replaced or repaired, the probability that it is impacted by at least one rockfall must be considered.


Geografie ◽  
2011 ◽  
Vol 116 (2) ◽  
pp. 144-155 ◽  
Author(s):  
Jan Klimeš

Rockfall hazard is assessed using Rockfor.net, which is one dimensional tool for assessing the protective function of forests against rockfall. Three sites where chosen to test the tool with different morphological and forest conditions. For each site, it was evaluated how the boulder size and forest composition affects the probability of the rocks to surpass the forested slope. The Rockfor.net was also used for back calculations of past event, which happened during the floods in July 1997 in the village of Bystřička in the Vsetínské vrchy Hills. In this case, also a partial quantitative risk assessment with suggestions for risk management was performed.


2013 ◽  
Vol 47 (4) ◽  
pp. 1664 ◽  
Author(s):  
A. Andrianopoulos ◽  
H. Saroglou ◽  
G. Tsiambaos

This paper presents and compares the main methods of hazard and risk assessment for road slopes. Hazard assessment is achieved by rating several parameters such as the slope’s geometry, traffic conditions, the geology and the rockmass properties, weather conditions, historical rockfall data etc. A hazard assessment can also be executed using 2D or 3D trajectory models, by combining the frequency of a rockfall and the kinetic energy of a falling rock. Several methodologies have been developed for risk assessment, varying from simplistic approaches to comprehensive probabilistic or quantitative risk assessment methods. Finally, the most suitable methods were used in order to assess the level of hazard and risk as an example (the data from two sections of the national road at Tempi Gorge, Greece) where many rockfall events occurred in the past few years.


2021 ◽  
pp. 112334
Author(s):  
Serena Santonicola ◽  
Stefania Albrizio ◽  
Maria Carmela Ferrante ◽  
Mercogliano Raffaelina

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