An equivalent fluid/equivalent medium approach for the numerical simulation of coastal landslides propagation: theory and case studies

Abstract

Abstract. Coastal and subaqueous landslides can be very dangerous phenomena since they are characterised by the additional risk of induced tsunamis, unlike their completelysubaerial counterparts. Numerical modelling of landslides propagation is a key step in forecasting the consequences of landslides. In this paper, a novel approach named Equivalent Fluid/Equivalent Medium (EFEM) has been developed. It adapts common numerical models and software that were originally designed for subaerial landslides in order to simulate the propagation of combined subaerial-subaqueous and completely-subaqueous landslides. Drag and buoyancy forces, the loss of energy at the landslide-water impact and peculiar mechanisms like hydroplaning can be suitably simulated by this approach; furthermore, the change in properties of the landslide's mass, which is encountered at the transition from the subaerial to the submerged environment, can be taken into account. The approach has been tested by modelling two documented coastal landslides (a debris flow and a rock slide at Lake Albano) using the DAN-W code. The results, which were achieved from the back-analyses, demonstrate the efficacy of the approach to simulate the propagation of different types of coastal landslides.

Mass Movement-Induced Tsunami Hazard on Perialpine Lake Lucerne (Switzerland): Scenarios and Numerical Experiments

“…For subaqueous mass movements, ''virtual'' rheology parameters are determined by back-analysis of a known event. This approach is often taken for runout analyses of submarine mass movements (e.g., IMRAN et al 2001;LOCAT et al 2009;MAZZANTI and BOZZANO 2009). The model uses a finite difference scheme to solve depth-averaged formulations of mass and momentum balance equations (BEGUERÍA et al 2009).…”

On the seismogenic increase of the ratio of the ULF geomagnetic field components

“…In conclusion, it is evident that some problems of fundamental importance in the investigation of seismo-magnetic signals are still remaining unresolved and a huge amount of research and a constructive criticism of the results are needed. Finally, I would like to emphasize that, as Eftaxias et al (2009) point out, a single analysis by itself cannot establish if an anomaly is a precursor or just a chance event. Therefore, as Uyeda et al (2009) suggest, a really multidisciplinary approach, which involves the investigation of physical, geochemical, hydrological and other parameters, could be useful to recognize an anomaly as a real seismogenic signature.…”

“…On the other hand, many other publications (e.g. Eftaxias et al, 2001;Pulinets and Boyarchuk, 2004;Varotsos, 2005;Molchanov and Hayakawa, 2008;Eftaxias et al, 2009) claim to observe electromagnetic earthquake precursors, sometimes many hundreds of kilometres from the earthquake, but with no clear co-seismic or post response effects. As a consequence, many in the scientific community doubt of the reality of claimed seismogenic electromagnetic signals and seriously question the claimed ability to develop short-term earthquake prediction capabilities using these precursory signatures.…”

Assessment of static flood modeling techniques: application to contrasting marshes flooded during Xynthia (western France)

“…LiDAR is a mapping technology that is increasingly used for coastal geomorphologic studies. This technology is appropriate for such analyses since it provides spatially dense and accurate topographic data (Chust et al, 2008;Goff et al, 2009;Haile and Rientjes, 2005;Mazzanti et al, 2009;Poulter and Halpin, 2008;Webster, 2010;Young et al, 2011). The LiDAR is a laser altimeter that measures the range from a platform with a position and altitude determined from GPS and an inertial measurement unit (IMU).…”