Satellites join watch on Naples' volcanic hinterland   Produced by the Italian National Research Council's Institute for Electromagnetic Sensing of the Environment (CNR-IREA), this animation shows Phlgerean Fields deformation events occurring between 1992 and 2000, as observed using Synthetic Aperture Radar Interferometry or InSAR using ERS-1 and -2 images. The animation is presented on a digital elevation model (DEM) of the area also obtained using InSAR, with a normal backscatter-intensity radar image of the Bay of Naples superimposed onto the three-dimensional relief map.   The Solfatara crater is the most famous feature of the Phlegrean Fields, first referred to back in the 1st Century BC. Its name comes from the Latin for 'land of sulphur'- Sulphur Terra. It is a subdued but still active shallow volcanic crater. Its many fumaroles and mud pools have made it a popular tourist attraction.   This Synthetic Aperture Radar (SAR) multitemporal colour composite image shows Naples and its bay. Naples, the largest city in southern Italy and capital of the Campania Region, can be seen as the large bright area on the northern tip of the Bay of Naples. The bay lies within an important volcanic province, with the volcano Mount Vesuvius and the Phlegrean Fields (Campi Flegrei) area being its active and ancient primary testimonies. The different colours shown by the sea in the bay indicate sea surface roughness caused by the winds which occurred during the dates of acquisition. The colour patches to the north of Naples represent crop fields. The image is made of three ERS-2 SAR PRI (Precision Radar Image) images acquired on different dates. A different RGB colour is assigned to each date of acquisition: Red: 11 February 2004, Green: 21 April 2004, Blue: 30 June 2004. The instrument has 25 metre resolution. Keeping watch from space on the Phlegrean Fields     A view of the Solfatara crater from 1717. The Phlegerean Fields remains a volcanically active area. The last eruption came in 1538, forming the new hill of Monte Nuovo.   A corner reflector for InSAR installed in the Solfatara crater during 2004 by the Vesuvius Observatory. Corner reflectors are built to strongly reflect the radar signal back to the satellite, so that any movement of the feature on which the reflector has been mounted can be measured in detail using InSAR.   The first section (a) shows a line of sight deformation map obtained from the descending ERS2 acquisitions of March and August 2000. (b) Shows the temporal evolution of the observed differential InSAR displacements, in the time interval June 1992-September 2000, for a point close to the location of the ACAE GPS permanent station. (c) Comparison of GPS measurements (ACAE site), projected along the radar line of sight and differential InSAR displacements in the time interval March-August 2000 (from Lanari et al., 2004).   Comparison of ground deformation time-series from SAR (up) and levelling (down) data on benchmark 25 (INGV-OV levelling line) (left): the good temporal coverage of SAR data allows the retrieval the information not available from levelling in the time interval between field measurements. Knowledge from MINERVA     The historical building of the Vesuvius Observatory, venue of the forthcoming workshop on monitoring volcanoes and seismically active areas with Earth Observation. Release date: 21 July 2005