Further developments on Kinematic Processing and Spatial Analysis of levelling control data of the Ancona 1982 landslide

Vertical movements were analysed with the results of 15 high precision levelling campaigns, carried out for the control of settlements in the Ancona 1982 landslide area. At the moment, seven years after the landslide took place, the vertical movements in the area are continuing and not slowing down as was expected and hoped for. The more than 7000 observed height differences of the 15 campaigns were processed simultaneosly in kinematic levelling adjustments, in wich for each benchmark a continuous function was estimated for the description of its height as a function of time. Two types of functions were used: low order polynomials and polynomial splines. The use of cubic splines turned out to be problematic because of the large time interval (2 years) between the 11th and 12th campaign. Cubic polynomials appeared to be surprisingly adequate to follow the movements patterns, taking into account the large interval of time and many repetitions. Spatial analysis of the kinematic parameters was carried out by collocation, after the removal of a trend by bicubic splines. A numerical experiment was carried out to investigate the characteristics of a collocation solution with stochastic and non stochastic parameters, in which all relevant parameters were estimated directly from the measurement data. An approximation of the inverse matrix was used to reduce the enormous amounts of CPU time and storage, which is required for the exact solution.