Ampliamento della rete altimetrica e risultati della campagna di livellazione di precisione all'Isola d'Ischia. Giugno 2010

Abstract

In this paper are shown the results obtained from Geometric High Precision Levelling survey performed at Ischia Island in June 2010. The measures have been carried out on the whole network of the island further expanded by increasing of the benchmarks and the establishment of new lines. The compensated height for each benchmark (Bm) are referred to Bm 1 located at Ischia harbour, were compared to those obtained in previous Levelling survey of 2003. The results show significant ground subsidence of different entities affecting various areas of the island. In addition, a further comparison with the measurements performed in 1987 confirms the existence of such differential movements characterised by subsidence velocity constant over time. At last, we found a good agreement between levelling and GPS velocities, calculated in time span 1997-2003.