ask 6 - Gubbio - Deliverable D21: Geological model of the Gubbio basin (Italy) for the characterization of local seismic response

Within the framework of the project S3 “Ground shaking scenarios for some strategic areas in Italy-Task6” the town of Gubbio has been selected as a test site to compute ground motion taking into account finite fault and site effects. Gubbio is located in central Italy, on the northern slopes of one of the many valleys characterising the central Appennines. The historical settlement is located on a rocky slope, while new developments extend on the Quaternary fluvio-lacustrine deposits filling the basin. The Gubbio basin was chosen as a test site for a number of reasons: its geomorphological setting is very common in central and southern Italy, the area is characterised by frequent near events of moderate magnitude (Mmax 6) and large amplifications were observed there for the Colfiorito seismic sequence of the 1997/98. In order to understand the mechanisms controlling the 3D seismic response of the basin, a subsurface model has been constructed. The reconstruction of the model has been done using data coming from different surveys (figure A). Several active and passive seismic measurements have been carried out in the plain, also favoured by the intense seismic activity typical of the area. These investigations mainly consisted of monitoring activities of 4 temporary transects of seismometric stations, operating between June 2005 and May 2006 and described in detail in PS3- Deliverables D22-D23. Two transects have been positioned perpendicularly to the valley axes (GFZ and Ge2 Transects), one parallel (INGV transect) and one near Gubbio (Ge1 transect). More than 300 local and regional earthquakes have been recorded, with maximum magnitude equal to 4. A 2D array was run as well from June to September 2006, to better understand the generation of surface waves. All data are collected in a GIS (Progetto S3 Deliverable D23) Parallel to these activities, ambient noise data have been collected in the field for 90 sites, using the single station technique for the estimation of the fundamental resonance frequencies. Furthermore, 4 noise measurements with a seismic array have been collected to build an S-wave velocity profile of soft sediments, considered representative for the whole plain. The geometry of the basin below 500 m of depth has been investigated through the acquisition of an active seismic line 4.5 km long, in correspondence of one of the transects. This has been used to perform a tomography of arrival times which allowed to recognise the position and shape of the reflecting horizons. As a final step the first 30 metres of deposits have been characterised over a 30 km2 area, using both stratigraphic investigations provided by the Gubbio Municipality and data collected from in-situ surveys and lab tests. In this deliverable we describe the input data for the 3D model of the Gubbio basin and we outline the steps performed to define the geometry, the layers and their seismic properties on the base of the experimental data collected during the project and of the available geological information.Progetto INGV-DPC S3 “Scenari di scuotimento in aree di interesse prioritario e/o strategico” (coord. F.Pacor e M. Mucciarelli)Published4.1. Metodologie sismologiche per l'ingegneria sismicaope

ask 6 - Gubbio - Deliverable D21: Geological model of the Gubbio basin (Italy) for the characterization of local seismic response

Within the framework of the project S3 “Ground shaking scenarios for some strategic areas in Italy-Task6” the town of Gubbio has been selected as a test site to compute ground motion taking into account finite fault and site effects. Gubbio is located in central Italy, on the northern slopes of one of the many valleys characterising the central Appennines. The historical settlement is located on a rocky slope, while new developments extend on the Quaternary fluvio-lacustrine deposits filling the basin. The Gubbio basin was chosen as a test site for a number of reasons: its geomorphological setting is very common in central and southern Italy, the area is characterised by frequent near events of moderate magnitude (Mmax 6) and large amplifications were observed there for the Colfiorito seismic sequence of the 1997/98. In order to understand the mechanisms controlling the 3D seismic response of the basin, a subsurface model has been constructed. The reconstruction of the model has been done using data coming from different surveys (figure A). Several active and passive seismic measurements have been carried out in the plain, also favoured by the intense seismic activity typical of the area. These investigations mainly consisted of monitoring activities of 4 temporary transects of seismometric stations, operating between June 2005 and May 2006 and described in detail in PS3- Deliverables D22-D23. Two transects have been positioned perpendicularly to the valley axes (GFZ and Ge2 Transects), one parallel (INGV transect) and one near Gubbio (Ge1 transect). More than 300 local and regional earthquakes have been recorded, with maximum magnitude equal to 4. A 2D array was run as well from June to September 2006, to better understand the generation of surface waves. All data are collected in a GIS (Progetto S3 Deliverable D23) Parallel to these activities, ambient noise data have been collected in the field for 90 sites, using the single station technique for the estimation of the fundamental resonance frequencies. Furthermore, 4 noise measurements with a seismic array have been collected to build an S-wave velocity profile of soft sediments, considered representative for the whole plain. The geometry of the basin below 500 m of depth has been investigated through the acquisition of an active seismic line 4.5 km long, in correspondence of one of the transects. This has been used to perform a tomography of arrival times which allowed to recognise the position and shape of the reflecting horizons. As a final step the first 30 metres of deposits have been characterised over a 30 km2 area, using both stratigraphic investigations provided by the Gubbio Municipality and data collected from in-situ surveys and lab tests. In this deliverable we describe the input data for the 3D model of the Gubbio basin and we outline the steps performed to define the geometry, the layers and their seismic properties on the base of the experimental data collected during the project and of the available geological information

Satellite A-DinSAR monitoring of the Vittoriano monument (Rome, Italy). Implications for heritage preservation

The "Vittoriano" monument, dedicated to king Vittorio Emanuele II, is one of the most famous cultural heritage landmarks in Rome (Italy), even because it hosts the Tomb of the unknown soldier, monument to the Italian fallen in wars. It was designed by the architect Giuseppe Sacconi at the end of 19th century and since the beginning of its construction, it has been affected by cracks and deformations. In the last years, such phenomena have become more evident, especially on the western side of the building. With the aim of understanding the causes of the deformation process and making a diagnosis of the soil-structure interaction of the Monument, a specific project has been undertaken between CERI Sapienza and the Lazio Museum Network.Satellite ADInSAR was performed to infer the recent deformational history of the main parts of the monument, by using medium and high-resolution SAR images acquired in double orbital geometry (ascending and descending) and covering the last two decades.Through the support of selected geological and lithotechnical data it was possible to interpret the deformational dynamics of the Vittoriano.The overall investigations allowed to better define the volume and the structures that have been involved in the deformation mechanisms, which is currently driving the overall process, in order to address effective mitigation measures. They are capable of backward analysing the deformational process, reconstructing the evolution of a phenomenon and above all capable of easily investigating large areas

Italian accelerometric archive: geological, geophysical and geotechnical investigations at strong-motion stations

Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sitesmanaged by the ItalianCivil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/ geotechnical investigation have been performed and describes the results of the promoted field surveys