SAR Interferometry for ground vertical displacement of small islands in the Venice Lagoon: the case of Murano Island

Abstract

Our knowledge of the dynamics of vertical ground movements plays a fundamental role in the study of the geomorphological processes, particularly for determining sediment deposition and erosion causes. The conservation of lagoon morphological structures such as salt marshes and tidal flats, besides erosion due to waves and currents, depends on their surface height with respect to the sea level that, for short periods, is primarily related to the land subsidence process and secondarily to eustasy. Ground vertical variations with respect to the sea level, even if small, can, in fact, trigger sediment erosion and deposition processes. To determine land displacement rates in small islands of the Venice Lagoon not covered by traditional surveys (levelling and differential GPS), SAR-based monitoring techniques, i.e. differential SAR interferometry (INSAR) and interferometric point target analysis (IPTA) from ERS-1 and ERS-2 satellites, were performed. We will use the Murano Island for our example in this contribution.