Evolution of techniques for monitoring unstable slopes

The monitoring of unstable or potentially unstable areas is a necessary operation every time you cannot remove the conditions of risk. So, in these cases landslide monitoring represents a very crucial mitigation operation, that is usually done by using conventional investigation devices. Generally, traditional landslide monitoring technologies, such as inclinometers, extensometers. LVDT and TDR based instrumentations, permit to define, if correctly positioned and with adequate accuracy, the critical values of displacement and/or acceleration into landslide body. In most cases, they do not allow real time warning signs to be generated, due to environmental induced errors. Remote-sensing monitoring instruments, such as 3D laser scanner, LIDAR and InSAR, are capable of inspecting an unstable slope with a high spatial and temporal frequency, but allow solely measurements of superficial displacements and deformations. The technological evolution exportable to the field of land instability monitoring is particularly hvely and allows the use of warning systems unthinkable just few years ago.