Morphological updating on the basis of integrated DTMs: study on the Albano and Nemi craters

The Colli Albani Volcano has recently developed
particular interest in the geophysical community
for some peculiar characteristics imputable to a
recent residual volcanic activity, thus evidencing that
it cannot be considered extinguished yet.
On April 2006 an airborne laser scanning (ALS) survey
of the Albano and Nemi craters has been carried
out to obtain a high resolution digital terrain model
(DTM) of the area. We have compared the accuracy
of the ALS heights with those obtained by a fast GPS
kinematic survey, obtaining maximum deviation
within 50 cm. Then, we have integrated the ALS survey
of the craters and the bathymetry of the Albano
lake to achieve a complete DTM, useful for morphological
studies. In addition, with a GNSS/RTK survey
(July 2007) we have estimated the Albano and
Nemi mean lake levels respectively at 288.16 m
and 319.02 m (asl). Based on the integrated DTM
and the newly estimated water level values, we have
evaluated about 21.7 106 of m3 the water volume
loss of the Albano lake from 1993 to 2007, with an
average rate of about 1.6 106 m3/yr.