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Geomatics for the control of ground subsidence and long-term phenomena

Keywords: Subsidence, Deformation Control, Archival Photogrammetry, Landslides, Glaciers, Laser Scanning
Fig. 1a. Integration of geometric levelling, spatial geodesy and SAR interferometry for the control of subsidence (Bitelli et al., 2015).
Fig.1b Speed of ground vertical movements in the valley of Emilia-Romagna, obtained by radar interferometric analysis 2006-2011 (Bitelli et al., 2015)
Fig.2 Multitemporal analysis of a landslide area (picture by Zanutta).
Fig.2 Multitemporal analysis of a glacier (picture by Zanutta).

Ground subsidence (of natural type or maninduced, e.g. by fluid withdrawal) can be a critical aspect in territory management. Geometrical surveying and monitoring are the first essential steps for the knowledge and understanding of the phenomenon, to detect entity, trend and spatial arrangement of the movements. Different techniques have been applied and integrated over the years by the team: from spirit leveling ('70s) to space geodesy (the '90s), and finally to the recent use of interferometric analysis of satellite radar images (PSInSAR). The research was carried out in national and international projects or with public authorities (Regions, Provinces, Municipalities, ARPA) and large private companies. The primary area of study is the Po Valley, with researches at regional, provincial or basin scale; a specific interest is furthermore towards coastal zones (EU FP7 project). The activity is also carried out at urban scale, monitoring single buildings and structures in city centers (e.g. Bologna) by high precision topographic techniques.

The work involves the production of technical specifications, design and realization of networks, monitoring through repeated measurement campaigns, quality verification, realization of GIS databases, production of maps of subsidence rate and other related products.

Other long-term phenomena can be studied using historical data, among them old aerial photograms. The so-called Archival Photogrammetry is made today through advanced digital techniques that complement the traditional photointerpretation for multi-temporal landslide studies, evolution of glaciers, change detection in urban centers, changes in the coastline, changes in forest cover.

For this purpose it is frequently necessary to realize Digital Terrain Models (DTM) or surface models (DSM) that allow for a metric definition of the 3D form; image matching techniques are applied on historical photogrammetric images or satellite stereo-couples, and airborne or terrestrial laser scanning is an effective solution for current situations.

Main publications

Bitelli G., Bonsignore F., Unguendoli M. (2000). Leveling and GPS networks for ground subsidence monitoring in the Southern Po Valley. Journal of Geodynamics, 30, 355-369.

Bitelli G., Vittuari L. (2006). Integrated methodologies for monitoring of subsidence effects on urban areas and buildings. Heritage Protection: construction aspects, Secon Hdgk, 147-156.

Bissoli R., Bitelli G., Bonsignore F., Rapino A., Vittuari L. (2010). Land subsidence in Emilia- Romagna Region, northern Italy: recent results. Land Subsidence, Associated Hazards and the Role of Natural Resources Development, IAHS Publ. 339, 307-311, Wallingford.

Bitelli G., Bonsignore F., Carbognin L., Ferretti A., Strozzi T., Teatini P., Tosi L., Vittuari L. (2010). Radar interferometry-based mapping of the present land subsidence along the low-lying northern Adriatic coast of Italy. Land Subsidence, Associated Hazards and the Role of Natural Resources Development, IAHS Publ. 339, 279-286.

Bitelli G., Bonsignore F., Del Conte S., Novali F., Pellegrino I., Vittuari L. (2014). Integrated use of Advanced InSAR and GPS data for subsidence monitoring, in: Engineering Geology for Society and Territory, (Lollino G. et al. eds), vol.5, III, 147-150.

Bitelli G., Bonsignore F., Vittuari L. (2015). Evolution of the techniques for subsidence monitoring at regional scale: the case of Emilia-Romagna region (Italy), Proc. Ninth International Symposium on Land Subsidence (NISOLS), Nagoya, Proc. IAHS, 372, 315–321.

Van der Krogt R., Bitelli G., Bremmer C., Capes R., Crosetto M., Cyziene J., Granizcki M., Hansen R., van Leijen F., Marsh S., Novali F., Schach Pedersen S., Westerhoff R. (2013). Monitoring subsidence of coastal lowland areas by satellite radar interferometry. Proc. 6th EARSeL Workshop on Remote Sensing of the Coastal Zone, Matera.

Strozzi T., Wegmüller U., Tosi L., Bitelli G., Spreckels V. (2001). Land Subsidence Monitoring with Differential SAR Interferometry. Photogrammetric Engineering and Remote Sensing, vol. 67, 2, 1261-1270.

P. Baldi, N. Cenni, M. Fabris, A. Zanutta (2008). Kinematics of a landslide derived from archival photogrammetry and GPS data. Geomorphology, 102, 435-444.

Bitelli G., Dubbini M., Zanutta A. (2004). Terrestrial laser scanning and digital photogrammetry techniques to monitor landslide bodies”. The Int Arch Photogram Rem Sens Spatial Inform Sci, Vol. XXXV, Part B, 246-251.

Spreafico M.C., Perotti L., Cervi F., Bacenetti M., Bitelli G., Girelli V.A., Mandanici E., Tini M.A., Borgatti L. (2015). Terrestrial Remote Sensing techniques to complement conventional geomechanical surveys for the assessment of landslide hazard: The San Leo case study (Italy), European Journal of Remote Sensing, 48, 639- 660

Bitelli G., Gatta G., Giorgini G., Minghetti A., Mognol A., Paselli E. (2006). Recupero a fini metrici di fotogrammi aerei storici per lo studio delle dinamiche territoriali in ambito urbano: un caso di studio. Atti X Conf. Naz. ASITA, 355-360.

Bitelli G., Gatta G., Landuzzi A., Vittuari L., Zanutta A. (2009). La fotogrammetria digitale d’archivio per lo studio multitemporale di un’area in frana nelle Prealpi vicentine, Atti 13a Conf. Naz. ASITA, 415-420.

D’Agata C., Zanutta A. (2007). Reconstruction by indirect source of the recent changes of a debris covered glacier (Brenva, Mont Blanc Massif, Italy). Methods, results and validation. Global and Planetary Change, 56, Issues 1-2, 57-68.

Zanutta A., Baldi P., Bitelli G., Cardinali M., Carrara A. (2006). Qualitative and quantitative photogrammetric techniques for multi-temporal landslide analysis”. Annals of Geophysics, vol.49, 1121-1134.

Research projects

ARPA Emilia-Romagna, on behalf of Regione Emilia-Romagna: Rilievo della subsidenza nella pianura emiliano-romagnola, Rete Regionale di monitoraggio della subsidenza (from 1997).

ASI (Agenzia Spaziale Italiana). Cosmo-SkyMed AO n. 2283: Integration of classical and space geodetic techniques for the study of vertical ground motions. Contract L/129/09/0 PI: Luca Vittuari (2010-2012).

EU FP7-SPACE-2009-1 ID: 242332 SUBCOAST - Assessing and Monitoring Subsidence Hazards in Coastal Lowland around Europe. A collaborative project aiming at developing a GMES-service for monitoring and forecasting subsidence hazards in coastal areas around Europe. Scient. Resp.: G. Bitelli (2010-2013).