The ground beneath our feet usually feels solid, but Earth’s land masses rest atop shifting tectonic plates that float on magma like colossal rafts on viscous seas. The plates are constantly moving, settling, and grinding against one another, causing earthquakes and volcanic eruptions, forming new mountains, and opening up new valleys. Landslides are powerful and potentially dangerous consequences of all this subterranean turbulence, and scientists are interested in predicting and modeling these events.
A plethora of mathematical formulas incorporating elements such as grain size, topography, gravity, and innumerable other factors has been created to describe the flow of solid particles in three dimensions, and researchers are constantly seeking to refine these models to match observations taken from real life events. Recently, researchers have recognized the importance of creating nonhydrostatic models, which do not rely on incorporating the interplay of gravity and pressure. Here Castro-Orgaz et al. add to this body of research by testing a group of equations known as Boussinesq-type gravity waves, which are used to describe waves of water, to analyze whether waves of solid materials can be described in the same way.
The team concludes that the Boussinesq-type gravity waves do, in fact, help describe the way avalanches and landslides propagate over time. In addition to refining their models, the scientists also suggest that this approach helps to describe the vertical motion of solids in a way that eliminates the need for many nongeneralizable assumptions previously used in models of granular flow. Instead, the assumptions are replaced with mathematics, opening a new framework for how researchers think about the flow of solids in three dimensions. (Journal of Geophysical Research: Earth Surface, doi:10.1002/2014JF003279, 2015).
—David Shultz, Freelance Writer
Citation: Shultz, D. (2015), Water waves provide insight into landslides and avalanche models, Eos, 96, doi:10.1029/2015EO037491. Published on 21 October 2015.