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Volume XIV |

Contribution of remote sensing InSAR and optical imagery to the identification of seismic faults in northeastern Algeria

Abstract: The assessment of seismic risk in northeastern Algeria is one of the main challenges for the region’s development. Seismic risk evaluation is based on the identification of active structures and the tracing of seismic faults. This approach faces a number of obstacles, including the complexity of the geological context, the weakness and imprecision of present geo-cartographic data, the predominance of argillaceous facies and the degradation of morphological expressions of deformation. Remote sensing is a valuable technique not only for the detection and cartography of active faults, but also for seismic risk management and the integration of these risks into sustainable development projects and territorial planning. In this study, we applied two remote sensing techniques: firstly, we have used optical image correlation. This correlation is performed between two images from the Sentinel 2A satellite, in descending mode, acquired at different times, before and after the earthquake. Secondly, we have used interferometric synthetic aperture radar (InSAR) which is based on the phase comparison of two SAR (synthetic aperture radar) images, used to construct the “Single Look Complex SLC” interferogram, from the Sentinel 1B satellite which were acquired at different times, but with similar acquisition geometries, covering the same area on the ground surface. The main objective of this study is to cartography and calculates the co-seismic displacements in our study region.

Volume XIV |

Rainfall deficit and excess within Oltenia region, Romania (1961-2020)

Abstract: Temporary rainfall deficit and excess impact both the natural environment and economic activities. Although rainfall does not display significant upward or downward trends in Central and Eastern Europe, global warming is expected to increase variability and associated risks. Thus, determining the annual and seasonal deviations of precipitation amounts at local scale is important in order to establish accurate trends of precipitation deficit and excess. We used 60-year time series (1961-2020) for 15 meteorological stations and a shorter series for one station (i.e., Slatina). The Standardized Precipitation Anomaly (SPA) indicates a predominance of normal years (32-50%), followed by dry and humid years, without an obvious latitudinal and altitudinal differentiation, while De Martonne aridity index (IaDM) emphasizes a latitudinal pattern: predominance of semi-humid years in the southern plain area, humid years in the northern plain area and the Getic Piedmont, very humid years in the Subcarpathians and extremely humid years in the mountains. Water deficit (IsDM < 20mm/°C) mainly affects the plain area during summer and autumn (50-60% of the seasons are arid and semiarid), but also the piedmont, where the share varies between 30 and 35%. Mann-Kendall (MK) test reveals the same pattern for annual values, namely, predominantly negative trends (statistically significant in the southwestern part of the region), which indicate an increase of both aridity and drought, including the higher hilly and mountain area. At seasonal level, autumn is the only period with positive, but not statistically significant trends, while in winter, spring and summer, trends are negative and statistically significant at certain stations. Consequently, drought-associated risks are projected to increase in the near future.

Volume XIV |

Applying impervious indices using Sentinel-2 data in semi-arid land (North-East Algeria)

Abstract: The urban area estimation in dry and semi-dry climate, is still a difficult. Therefore, identify a reliable impervious index is critical. For that reason, Ain Azel city that located in semi-arid land of North-East Algeria, was the area of test of three impervious indices, namely: the Built-up Area Index (BAI), the Normalized Impervious Surface Index (NISI) and the Urban Area Index (UAI). These indices were derived from Sentinel-2 data and subjected to the Support Vector Machine (SVM) classification method, to extract built-up area class. The accuracy assessment results showed that the Overall accuracy (Oa) of the NISI index achieved 92,67 %, which is a little less compared to the (Oa) of UAI index which is about 93.67 %. Based on this, the both indices provided satisfactory result, although the UAI index, relatively, overestimated the built-up area. However, the BAI index that use the Blue and Near-Infrared bands is sufficiently discriminative between highly similar of buildings materials and dry soil; the BAI index produced the accurate built-up mapping with well detection of road networks with (Oa) achieved 95.67% and the highest kappa coefficient which is about 86.54 %. This is due to BAI band’s degree of sensitivity and their high spatial resolution of 10 m. Consequently, the SVM segmentation-based BAI index worked well and the result is promising for accurate modeling of cities with same environment condition, for its sustainable development. However, the performance level evaluation of indices applied in this study, should be retested over different regions in dry land.

Volume XIV |

Impact of urban morphology on walkability: A case study of the Colonne neighborhood in Annaba, Algeria

Abstract: Walkability, as a fundamental concept of active mobility, plays a crucial role in improving the quality of life in urban environments. This article aims to examine thoroughly the impact of urban morphology on pedestrian mobility, by analyzing the urban form of the Colonne neighborhood located in the city of Annaba, Algeria. Two approaches are used in this research: a quantitative approach using the Walkability Index, supported by the International Physical Activity and Environment Network (IPEN) project, and a qualitative approach based on a field questionnaire survey. The four variables within the Walkability Index are assessed using a Geographic Information System (GIS) to classify them individually. The results are then compared across zones and street segments most frequented by the respondents , according to the survey. The comparison explicitly reveals a strong positive correlation between the Walkability Index values and people’s tendency to walk. Moreover, the two main streets record the highest walkability values and are the most frequented throughout the neighborhood. This confirms the idea that walkability and levels of outdoor physical activity are strongly influenced by the urban morphology of the neighborhood. These results support the hypothesis that there is a strong relationship between urban morphology and walking practices within urban spaces. Further evaluation of other neighborhoods in Annaba, with varying urban morphologies, could enrich the understanding of walkability across the region.

Volume XIV |

Perceived health effects of traffic congestion among commuters in Ota city, Nigeria

Abstract: Increased automobile dependency, rising car ownership rates, uncontrolled population growth and sporadic industrial and commercial development have led to unprecedented levels of traffic congestion in rapidly expanding cities, resulting in devastating socio-economic consequences. Against this backdrop, this study investigates the perceived health effects of traffic congestion among commuters in Ota City, Nigeria, as existing literature lacks a direct focus on this aspect within the African context. Specifically, it examines commuters’ socio-economic status (SES) and travel behavior, evaluates the nature of traffic congestion and its contributing factors in Ota City and assesses the health consequences of congestion on commuters. Employing a cross-sectional research design, the study distributed 400 questionnaires to commuters at major motor parks in the city using systematic sampling. Key findings reveal that a significant proportion of respondents are male, possess formal education, predominantly travel within Ota City and rely mainly on taxis for both intra-city and inter-city commuting. The majority, approximately 80%, experience over 30 minutes of traffic congestion while traveling along major routes, with recurring congestion being predominant (46.2%). Factors such as unregulated loading and unloading, queuing discipline, on-street parking, street vending and road failures are top-ranked primary contributors to congestion. Furthermore, common health implications reported by commuters include backaches, body pain, swollen legs, headaches and fatigue. Regression analysis indicates a significant correlation between the severity of traffic congestion and the health implications experienced by commuters (F12/387 15.727, p=0.000<0.05). The study concludes by recommending effective strategies to mitigate persistent traffic congestion and its associated health effects among commuters in Ota City.