2. VOLUMES COMPUTATION
The total volume of the masses involved in the event (fig. 5) has been
computed by adding the volumes for each Square mesh, which were previous-
ly determined by applying the bilinear interpolation of the heights pre-
dicted via collocation:
] /!
v=, I Vi = Z. I f. fo 2T
with £j = Su Pj eg VERY .
For every patch the four unknown parameters of the interpolation have
been evaluated, by taking as reference values the predicted ^z values on
their four corners.
The results point out a lack of mass of about 550,000 m?, according to a
previous computation made by applying the finite elements method (Colom-
bo et al., 1986). A window zone has been selected in the global area, as
suggested by the geological study.
3. SHAPE PARAMETER ANALYSIS
Plotting the slopes, also predicted via collocation (fig. 6), allows for
the identification of the two points of maximum (positive) and minimum
(negative) variations. The direction of the straight line connecting
these two focuses can be considered as a very meaningful parameter for
the global movement.
Along this line, taking into account the local bending of the predicted
surface (fig. 7), the vertical section of the landslide's body has been
drawn. Two separate diagrams show the shape of the terrain (fig. 8/a)
and the Az variations (fig. 8/b). Moreover, some characteristics lines
reproducing the landslide bounds, the break line between the sinking area
and the rising one (by mass accumulation) due to the event, are pointed
out in fig. 9. The lines which separate areas with different curvature,
derived from local bending distribution (see fig. 7), are drawn in the
same plot.
It has not been possible to detect the total amount of the horizontal
displacement, because its value is around 20 meters, as it has been found
by means of already available digital displacement models. Therefore
the prediction should be done in a grid denser than that one utilized.
However, it will very likely be possible to improve at the same time the
computing procedures enhancing the hardware and software facilities.
The good results until now achieved allow to foresee further developments
of the method: some other height samples gathered from different sources
could be tested, and predictions in denser grids could be performed too.
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