Geomatic methods for punctual and areal control of surface changes due to landslide phenomena

Landslides are one of the major causes of natural disasters worldwide. In the field of landslidestudies, much effort has been put into investigating landslide causes and mechanisms.Geodetic and Remote Sensing methods, in addition to geological, geotechnical andgeophysical techniques are fundamental to study and understand landslides. In fact, besidesthe use of geotechnical devices that are mainly devoted to on-site and punctual monitoring,Geomatics may play a relevant role in the assessment of superficial movements, especially onlarge and non accessible areas. Nowadays, the integration of several techniques allows a widerange of landslide types in different environmental contexts to be surveyed and controlled.Besides alerting and alarming purposes, the acquired data set may also serve in numericalmodeling, from the set-up of 2D- and 3D-descriptions of the slope, up to the validation of theresults.Differential Leveling, GNSS, Total Station, Laser Scanning (both airborne andterrestrial), high resolution space-borne imagery, Photogrammetry and Radar Interferometrycan be used in each step of landslide studies, from site characterization onwards: to detect andto map landslide areas; to classify landslide type, state and style of activity; to monitorlandslide activity; to evaluate the probability of occurrence within a given area in landslidehazard assessment; in structural and non-structural mitigation of landslide risk.The monitoring of surface displacement may be based on topographic punctualobservations or on non-contact methods.Point-based measurements are carried out on the field by means of GNSS (by static, faststatic, kinematic, Real Time Kinematic methods) or by Total Stations (triangulation,trilateration, intersection - resection, traverses, radial sides hot methods and more generally 3D or 2D networks). The elevations are determined by spirit or trigonometric leveling. Allthese techniques deliver 1D, 2D or 3D coordinates of some isolated point on the landslide body, and, therefore, an estimate of movement rates, along with the evaluation of theirprecision.Non-contact methods are becoming a widespread technique to measure wide areas and toquantify landform changes, providing information on the displacement fields or on surfacechanges of point clouds. By the interpolation of point clouds, Digital Elevation Models(DEMs) are generated as support of geomorphological survey and mapping. Then, by multitemporal DEMs comparisons, morphological changes can be assessed on a metrical basis.This paper describes the classical and modern methods that may be adopted for analyzingsuperficial landslide movements, focusing on pros and cons of each method with respect togeological, geomorphological and environmental conditions. © 2010 Nova Science Publishers, Inc. All rights reserved.