A summary of CRMD new research on landslides using multi-temporal InSAR techniques based on Sentinel-1 data

The new landslide research direction at CRMD aims to improve and develop new applications of ground-based validation techniques of satellite radar interferometry displacement products, based on Sentinel-1 data. The test area is the high slope instability ridge of the Carpathian and Subcarpathian Prahova Valley due to natural and anthropogenic factors. We use sets of single polarized synthetic aperture radar (SAR) satellite data acquired by historical (i.e., ERS-1/-2 and ENVISAT) and recent (Sentinel-1) satellites, and multi-temporal radar interferometry (InSAR) methodologies to provide maps of line-of-sight displacements. We apply some of the most advanced differential interferometric Synthetic Aperture Radar techniques at the moment, Persistent Scatterer Interferometry (PSI) and Small BASeline Subset (SBAS); both of them are applied for depicting areal or point deformations. Deformation maps and time series are integrated with Geographical Information System (GIS) multilayer analysis results derived from classical methodologies (i.e., geological and geomorphological methods), and field research. InSAR analyzes are calibrated and validated using GNSS techniques and GIS slope modelling based on Lidar and radar obtained DEMs. The short-term results are highly reliable interferometric measurements. On a long term, the results imply the understanding of slope dynamic in the context of major human environmental change. The latter achievement could offer the support to successful risk mitigation methodologies in mountain areas

Identifying limitations of Permanent Scatterers Interferometry for buildings monitoring

. The Permanent Scatterer Interferometry (PSI) represents one of the most advanced monitoring techniques from space. In the current paper, the technique is applied for observing the movement behaviors of buildings found in the center of Romania’s capital, Bucharest, in order to verify whether there is a possibility to differentiate among patterns. The main hypothesis of the research is that buildings respond to ground movement differently depending on their characteristics, such as age, construction material, and structure or height regime. Twenty-seven images acquired by the German TerraSAR-X (TSX) satellite, were processed in order to depict ground level deformations. The buildings were analyzed by classifying them in different categories, depending on their earthquake vulnerability, height and location. The results suggested that the movement patterns identified by the satellite depend mainly on the spatial distribution of the buildings

Monitoring historical urban infrastructure using multi-temporal InSAR techniques

Ranked tenth in the world regarding seismic risk, Bucharest is the most seismically exposed capital in Europe and has the highest risk among Romanian cities. Location on two faults, high population and preponderantly old buildings make Bucharest even more vulnerable to strong earthquakes that occur periodically in Romania. In order to prevent major live and material losses in the future, authorities are trying to generate a map of buildings classified according to the risk of collapsing at the next earthquakes. In an attempt to reduce the time necessary to identify buildings at high risk we propose using InSAR technology that detects fine movements of objects. In our study we are interested to find out if satellite measurements are able to distinguish between effects produced by damage and those brought about as a result of changes in for example non-structural components and the environmental conditions. Also it is important to consider whether the dynamic characteristics can be identified with the required accuracy using InSAR techniques. In this purpose we compare building behavior identified from satellite data with that resulted from terrestrial monitoring using high precision techniques. In the current paper, we present the methodology of rating buildings using health indices, and discuss possible outcomes

The evolution of the fluvial islets hydrodinamic shape. Applications for Danube's Islets between Giurgiu and Oltenita towns

This paper presents a brief analysis on the fluvial islets hydrodynamic shape. Proposed by the Wyrick (2005) and Wyrick & Klingeman (2011), the hydrodynamic shape criteria refers ”to the subaerial planform shape of the river islets”. According to them, these geomorphological landforms can have a streamlined shape, an angular aspect or irregular shape. Except for the last category, each of the other types has several subtypes. For this case study we selected the fluvial islets from the Danube River, the sector situated between Giurgiu and Oltenita towns. It can be observed that, nowadays (2017) there are five new islets unlike between 1889 and 1916 and most of the river islets have an irregular shape. Also, in the literature it is mentioned that there might be a connection between the shape and age of islets. So, in our study, we applied a Chi-Square Test to check this relation. The results show that there is a possible association between the shape and the age of the Danube's Islets

The hydrological regime of the Prahova River along Carpathian and Subcarpathian stretch

The objective of this study is to analyze the hydrological regime of the Prahova River along its Carpathian and Subcarpathian stretches. The study reach has a length of 56 km and is situated between the Prahova River source and the downstream confluence with its main left tributary, the Doftana River. The description of the hydrological regime of the Prahova River is based on the statistical analysis of the climatic and hydrological data recorded at the meteorological stations and hydrometric stations in the area of interest. In order to understand the hydrological regime of the Prahova River, we focused on the following aspects: (1) sources of supply, (2) climatic factors (temperature regime, precipitation regime), (3) the mean flow, (4) the maximum flow (floods), (5) the sediment discharge and (6) the thermal and freezing regime of the Prahova River. The importance of this study lies in the need to know the hydrological regime that plays a leading role in the study of the morphodynamics of the Prahova River channel

Cultural Landscapes in Historical Cartography: Landscape Gardens in the “Green” Bucharest of 1789

At the end of the 18th century, Bucharest, the capital of Romania, was a “green” city (having large orchards, vineyards and even patches of wood), which apparently was in no need of landscape gardens. However, historical cartography and the written documents testify their existence. The study relies on large-scale historical maps (1:2000 – 1:7250), which were processed in a GIS Open Source Environment (QGIS software). The Purcel map (1789) shows the existence of eleven landscape gardens totalling an area of 8.63 ha. The retrieval of their exact location may serve as a starting point for a future web page meant to offer virtual travels and to bring back to light the old townscapes through paintings, vintage photos, testimonials of foreign travelers, documents, etc. All these can prove to be very useful for understanding the emotional geography of the old Bucharest, which arouses a particular interest, as shown by the results of a questionnaire applied on 134 subjects

Surveying the Surveyors to Address Risk Perception and Adaptive Behaviour Cross-study Comparability

International audienceOne of the key challenges for risk, vulnerability, and resilience research is how to address the role of risk perceptions and how perceptions influence behaviour. It remains unclear why people fail to act adaptively to reduce future losses, even when there is ever richer information available on natural and human-made hazards (flood, drought, etc.). The current fragmentation of the field makes it an uphill battle to cross-validate the results of existing independent case studies. This, in turn, hinders comparability and transferability across scales and contexts and hampers recommendations for policy and risk management. To improve the ability of researchers in the field to work together and build cumulative knowledge, we question whether we could agree on (1) a common list of minimal requirements to compare studies, (2) shared criteria to address context-specific aspects of countries and regions, and (3) a selection of questions allowing for comparability and long-term monitoring. To map current research practices and move in this direction, we conducted an international survey – the Risk Perception and Behaviour Survey of Surveyors (Risk-SoS). We find that most studies are exploratory in nature and often overlook theoretical efforts that would enable the comparison of results and an accumulation of evidence. While the diversity of approaches is an asset, the robustness of methods is an investment. Surveyors report a tendency to reproduce past research design choices but express frustration with this trend, hinting at a turning point. To bridge the persisting gaps, we offer several recommendations for future studies, particularly grounding research design in theory, improving the formalisation of methods, and formally comparing theories and constructs, methods and explanations while collecting the most-in-use themes and variables and controlling for the most-in-use explanations