The role of deep-seated ground deformation in the Early Warning System. The experience using robotized inclinometer system.

In the field of geohazards, early warning systems represent a key element to coexist with thegeological risks and to manage ordinary or emergency scenarios. Modern monitoringsystems allow to follow up the evolution of the phenomena in near real time and tosupport decision-maker in a trustworthy and reliable way. These systems must benecessarily coupled with a robust interpretative model that must be periodically updatedalso using the acquired monitoring data. Particular attention must be given to themulti-instrumental analysis to the validation of each instrument dataset and to assure a globalperspective of the observed phenomena. In recent years, we have observed a strongdevelopment of technologies to measure dynamics of the surface topography andthe related structures/infrastructures with large scale (remote sensing) or a localscale (single landslide) approach. Many of these technologies are used to measuredisplacements and/or deformations. However, the measurement of these parametersdoes not always allow a fully description of the kinematic of the phenomena, sinceoften the surface measurements represent a sum of deformations that develop in acomplex way in the subsoil. The kinematic of the landslide, the involved volumes andtherefore the interaction with the elements at risk can be heavily influenced bydeep-seated ground deformations. In this context, Geohazard Monitoring Group(GMG) of IRPI-CNR has developed a robotic measuring system for the acquisition ofdeep-seated ground deformations and in particular the deep horizontal displacements. Thisinstrumentation combines the advantages of the traditional measurements (manual doublereadings 0/180˚) with a robotized approach that improves the results in term of revisittime, repeatability and accuracy. The robotized device also called as AutomatedInclinometer System (AIS), allows exploring automatically all the length of theborehole (up to 120m tube length) with just one inclinometer probe. All the cables(probe signal and power supply) are replaced with a thin polyethylene cable (φ2mm) only to sustain and move the probe up/down into a standard inclinometerborehole. The AIS was extensively used in landslide monitoring networks in theAlps areas obtaining interesting results in terms of: i) definition of the deep andsurface kinematics of the observed phenomena ii) evaluation of the displacementsaccelerations iii) relationship with rainfalls/snow melting and piezometric water levels.AIS represent a reliable possibility to realize a more complete integrated networkfor the landslide interpretation and to realize a more efficient and complete EWS. [ABSTRACT FROM AUTHOR]