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The GeoRisk project, reference PID2019-103974RB-I00 is funded by MCIN/ AEI/10.13039/501100011033.

Integration of high-resolution (HR) input data for rockfall characterization and 3D/4D modelling

The availability of new geomatic techniques allows new challenges in rockfall susceptibility and hazard assessment to be addressed. We will focus on three issues that have a direct effect on the occurrence of rockfalls and their propagation: generation/source areas, magnitude frequency relation and trajectory definition. Therefore, the objectives are:

Objective 2a: To improve the procedure for identifying potentially unstable rock blocks (rockfall sources) by combining high-resolution (TLS-generated) point clouds, (UAV-generated) digital photogrammetry and detailed geostructural analysis, particularly focussed on joint persistence and rock bridges.

Objective 2b: QRA is very sensitive, to provide a correct definition of the rate magnitude/frequency. Therefore, it is an important parameter to consider. To achieve the most realistic approximation of this relation, the best option is to obtain data from a TLS and/or photogrammetry monitoring. To achieve this, we must analyse which methodology is most suitable for monitoring the rocky massif, data processing and multitemporal models comparison to obtain this relation for varying lithology. We propose several options: campaigns with photogrammetry from UAV and TLS, and continuous campaigns with terrestrial photogrammetry.

Using the data provided by the abovementioned monitoring systems we propose analysing the influence of the size of the potential block, the failure mechanism, and the lithology on premonitory deformation of potentially unstable rock masses. We expect to identify factors that favour or prevent displacements precursory to the failure.

Objective 2c: To further analyse the relationship between impact forces and fragmentation and, particularly, to investigate the existence of a possible threshold. We propose investigating the influence of these new findings (distributed roughness and impact forces) on the results of the trajectory simulation (RockGIS software) by means of a sensitivity analysis.