• About the project
• Objective
• Summary
• Implementation plan
• Results
• Tasks
  • Phase 1
  • Phase 2
  • Phase 3
  • Phase 4
  • Phase 5
• Publications

Results

Project REVEAL is based on Bucharest’s seismic reality, the European capital with the highest seismic risk. Within this space characterised by the potential instabilities of the seismic context, the human and the natural systems are analysed across historic interactions with specific, contextual, space-time determinants. The project represents the first approach of its kind, where identified morphodynamic through modern means offered by remote sensing is correlated with vulnerabilities of inhabited spaces, at buildings, transport, and household level. This is achieved through analysing the city’s development path in regard to social and economic conditions. Diachronic analyses of historical maps, GIS and RS applications, all reconstruct the historical space of human-environment interaction. The space’s vulnerability is estimated as fit/misfit between local development tendencies and the shape of geomorphological and cultural systems. Understanding the vulnerability of a space can have practical and theoretical long-term implications in the city’s seismic context, offering support for urban risk mitigation efforts. Results are novel and remarkable, both at natural and human component level.

At natural space level, for the first time there is a mapping and dating of terraces in Bucharest, within the context of the evolution of the Danubian system in relation to Black Sea oscillations. The resulting terrace maps are partially different from previous works.

Satellite interferometry, which relies on high resolution radar images, was applied on sets of both historical (ERS, Envisat) and current radar satellite data (TSX). Reconstructing the historic DEM from map pages from 1911 and digital land modelling with LiDAR helped complete the interferometry information. Absolute dating of samples from the loess and terrace river deposits through optically stimulated luminescence (SAR-OSL) further widened the morphodynamic framework within the context of climatic, tectonic, and eustatic Pleistocene-Quaternary determinants.

At historical space-time scale, we used historical mapping to reconstruct the way the city was spatially and functionally organised, and also to observe the interaction and impact humans have had with and on the city’s natural environment. Results are novel because they identify vulnerabilities and potential instabilities with particular relevance in the city’s seismic context. On such example would be the significant loss in urban biodiversity and the complex vulnerability which this brings about through the loss of wetlands along the two rivers that drain the city.

Project stages in 2014 and 2015 focused solely on the human component. Drawing from seismic hazard space analyses we carried out social, economic, and built environment, vulnerability analyses, including analyses of transport networks. Risk analyses for different earthquake scenarios were also run. Input data came from three censuses in 1992, 2002, and 2011. Despite significant issues brought about by changes to the census tracts limits to anonymise the data, errors at raw data level, and a high number of missing entries (the latter issue particularly for the 2011 data), we could obtain results which are verifiable in-site, and we could identify tends and spatial patterns in the city’s seismic vulnerability. Multi-criterial methods were used for the vulnerability analyses which allowed the processing of a large number of both quantitative and qualitative variables. Uncertainty and sensitivity analyses were carried out on both entry data and weights in order to verify results stability and achieve a hierarchy for the resulting vulnerability hotspots. Vulnerability analyses were run in relation to three seismic scenarios: two historical (from 1977 and 1990) and one for the maximum theoretically possible (Marmureanu, 2010). Analysis of statistical data at sector level revealed trends for seismic vulnerability for the period (1992-2011), with a maximum deterioration to be found in sector 5. In spite of changes to the census tracts, the issues surrounding the worsening situation in areas with social problems known since 1990, such as Ferentari or Rahova, remain quite evident. Results also point to a previously overlooked phenomenon: increased vulnerability in areas because of urban isolation. The neighbourhood of Giulesti-Sarbi is in this situation as it is connected to the city via only one access route.

Seismic risk analyses implied a natural continuation of the vulnerability analyses. Quantitative risk assessments were carried out for the building stock, transport system, and at population level, for all three seismic scenarios, on census data from 2002 and 2011. Results matched real values recorded for the 1977 earthquake, which further validated the methodology developed by the project.