Integrated geomorphological mapping in the north-western sector of Agrigento (Italy)

The geomorphologicalmap is an essential tool to performa proper urban planning inmountainous or hilly areas. In this paper amultidisciplinary approach to derive a 1:2000 geomorphologicalmap is described.The proposedmethodology consists of the integration between aerial photographs, acquired in 2003, and four datasets of Persistent Scatterer Interferometry (PSI) measures to update a pre-existing landslide inventory. The integrated data were used to achieve a validated geomorphological map by means of a geomorphological survey. The study area is located in southern Italy (Agrigento, Sicily). The city of Agrigento, included in the World Heritage List of UNESCO in 1997, is located on the Girgenti hill which is exposed on its northern side, to several landslide phenomena. The top of the hill is characterized by the presence of part of the cultural heritage of the city and is affected by rockfalls, rock topples and shallow-seated landslides, representing a serious risk for important historical buildings. The results demonstrate the validity of this method to achieve a suitable tool in landscape and cultural heritage management. © 2012 Journal of Maps

Ground instability in the old town of Agrigento (Italy) depicted by on-site investigations and Persistent Scatterers data

We combine on-site investigations with the interpretation of satellite Persistent Scatterers (PS) to analyse ground instability in the historic town of Agrigento, Italy. Geological and geomorphologic surveys, together with geostructural and kinematic analyses, depict the deformational patterns of the northwestern sector of the town, previously documented by extensive literature available for the neighbouring Valley of the Temples. The geological and geomorphologic maps are reconstructed by combining bibliographic studies, field surveys and aerial stereo-interpretation. ERS-1/2 PS data reveal deformation velocities up to 18–20 mm yr<sup>−1</sup> in 1992–2000 over the Addolorata landslide, and a sudden motion of 1.6 cm over the Bishop's Seminary in 1999. RADARSAT-1 PS data highlight velocities of 3.0 mm yr<sup>−1</sup> for St. Gerlando's Cathedral and reveals worsening of its structural instability since 2006. Ground instability of the town is controlled by low quality and high fracturing of the Agrigento formation rock masses, and the remarkable contrast between different mechanical behaviours of its calcarenite (brittle), silt and clay (plastic) facies. Slow landslides and widespread erosion are also recognised in the clays of the underlying Monte Narbone formation. Coexistence of these factors induces progressive retrogression of the edge of the Girgenti hill and damages the overlying historic buildings, whose stability and safe accessibility are nowadays almost compromised

Exploitation of large archives of ERS and ENVISAT C-band SAR data to characterize ground deformations

In the last few years, several advances have been made in the use of radar images to detect, map and monitor ground deformations. DInSAR (Differential Synthetic Aperture Radar Interferometry) and A-DInSAR/PSI (Advanced DInSAR/Persistent Scatterers Interferometry) technologies have been successfully applied in the study of deformation phenomena induced by, for example, active tectonics, volcanic activity, ground water exploitation, mining, and landslides, both at local and regional scales. In this paper, the existing European Space Agency (ESA) archives (acquired as part of the FP7-DORIS project), which were collected by the ERS-1/2 and ENVISAT satellites operating in the microwave C-band, were analyzed and exploited to understand the dynamics of landslide and subsidence phenomena. In particular, this paper presents the results obtained as part of the FP7-DORIS project to demonstrate that the full exploitation of very long deformation time series (more than 15 years) can play a key role in understanding the dynamics of natural and human-induced hazards. © 2013 by the authors

Coupling heat transfer modelling to ALBA model for full predictions from meteorology

International audienceHigh Rate Algal-Bacterial Ponds (HRABP) are often considered as an interesting solution for reducing the energy demand due to oxygenation in wastewater treatment, since oxygen is produced by the microalgae during photosynthesis. Modelling these complex dynamical processes is a challenging task since it is subjected to the solar fluxes imposing permanent fluctuations in light and temperature. The ALBA model was developed to represent this process, and validated with 623 days of outdoor measurements, in two different locations and for the four seasons. However, so far this model -as all the other existing models- was not fully predictive since it was requiring the measurement of the water temperature.The objective of this work is to upgrade the ALgae-BActeria (ALBA) model, coupling it with a physical model predicting the evolution of temperature in the HRABP and presenting a novel structure for the pH submodel implementation. A heat-transfer model was developed and coupled to this model. It was able to accurately (with a standard error of 1.5°C) predict the temperature along the year. When coupled to the ALBA model, full predictions only based on meteorological data become possible. The predictions are hardly affected compared to using the actual measured temperature, resulting in an overall excellent capability to predict the process behaviour so that it can be further used for the system optimization, and for testing scenarios under very different operating and weather conditions