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Summary of Proposal LAN1444

TitleGround Subsidence in Bucharest, Romania based on Historical and Recent Data
Investigator Armas, Iuliana - University of Bucharest, Faculty of Geography
Team Member
Necsoiu, Marius - Southwest Research Institute, Geoscience and Engineering Devision
SummaryThe objective of the project is to identify trends in city’s land subsidence via diachronic cartography and radar interferometry (InSAR) techniques and to correlate them with declining groundwater levels (due to groundwater extraction) and construction. In the last 100 years, city’s buildings, street networks and sewerage systems have disorganized and are still disorganizing the structure of the natural edifice, resulted from the evolution in the fluvial-lacustrine system in the superior Pleistocene-Holocene period. The current intense construction activities represent a pressure on the environment that cannot be easily quantified, requiring an interdisciplinary methodological approach. For these propose, the research will focus on the spatial identification of historically changes of the urban shape of Bucharest, as a precondition for ground deformation.The specific evolution of the space is marked by the disorganization of the circular structure of the parochial units from the XVI-XVII centuries (Harhoiu, 1997; Papazoglu, 2000; Ianos and Tălângă, 2005; Gherasim, 2007). As a result of anthropogenic modification of space by construction and industrial exploitation of groundwater, at the level of Bucharest two major consequences with a high risk potential can be observed: a) changed level of aquifer layers, and sometimes even of their location, with frequent fluctuations and b) settlements on alignments of old affluents especially of the Dambovita River. Both processes lead to settlement phenomena, having serious consequences, leaving visible cracks in the old building, damaging roads faster, etc. The old rubbish holes of the city or the historic brick exploitations, now largely man filled surfaces and supporting constructions, also present vertical dynamics and vulnerabilisation of constructions in the seismic context of the city. To identify (structural-) functional historical changes we will first employ a diachronic cartography method (Favory and Raynaud, 1992; Morant et al, 1995; Bevilacqua, 1992; Rosselli and Paulmier, 2006). The principal development lines of the city from the perspective of the urban texture will be identified based on a cartographic material (i.e., 1791, 1856, 1900, 1911, 1921, 1940, 1972, 1998, 2008), orthophotoimagery (i.e., 2005 and 2007 flights) which will later be combined with products generated by analysis of high resolution optical and radar satellite images. Specifically, maps of deformation based on radar interferometry usingC- and X-band datawill be essential in quantifying the changes from recent years. Consequently we will employ TanDEM-X data and InSAR, focusing on areas of maximum displacement identified in historical data as well as in the displacement map produced by a recent 7-years C-band differential InSAR-based study (ASRC, 2010). The proposed project will further identify the effects of the vulnerabilization of the urban environment, in the same time linking them with the adapting mechanisms. This will be done through the means of innovative spatial modeling techniques, like multicriterial analysis (i.e., Canonical Analysis, Factorial Analysis of Correspondences) and by spatial viewing applications. Designing and creating an information management and statistical analysis of spatial data will involve thedeveloping of a GIS that will facilitate multicriterial data processing and spatial viewing of products previously generated by diachronic cartography and InSAR. This work is funded in part by the National Research Council (CNCS) of Romaniavia project PN-II-ID-PCE-2011-3-0175 having Prof. Armas as the PI. Additional funding may be provided by SwRI via the Internal Research and Development Program.

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