Flood Hazard Mapping in a Reservoir-regulated River Basin using Sentinel-1 imagery: The Case of Serres Basin.

International audienceFlood is a natural disaster and causes loss of life and property destruction. Flood hazard Monitoring and Mapping is of great importance because it represents a significant contribution to risk management. The present study investigated the flood event occurred in 2014-2015 at Serres Basin, a reservoir-regulated river basin, aiming to understand its spatio-temporal dynamic of the flood hazard. Within the Strymon River basin, a transboundary river outflows to Kerkini Lake-reservoir which has the role of regulating water flow to downstream for irrigation purposes and flood protection. For this research, a dataset of Sentinel-1 SAR GRD images was collected and processed covering the period of October 2014 – October 2015. Based on SAR images binary water and non-water products were generated and interpreted. Satellite Earth Observation has proved to be an effective tool for hazard dynamic extension mapping and in combination with hydro-meteorological data can be a significant knowledge in flood disaster management

Detection of ground deformation in the broader area of Sharm El-Shiekh (Sinai Peninsula, Egypt) by SAR interferometry

Sharm El-Shiekh area is located in the most southern part of Sinai Peninsula boarded by the Gulf of Suez to the west and by the Gulf of Aqaba to the east. The present study concerns the application of Multibaseline/Stacking Differential SAR Interferometry (DInSAR) in order to monitor ground deformation rates in the southern part of Sharm El-Shiekh area. The specific technique was applied in order to reduce the influence of atmospheric effects on ground deformation estimates. For this purpose a total number of 24 ENVISAT ASAR scenes covering the period between 2002 and 2008 were processed and analysed. Interferometric results show both patterns of uplift and downlift in the study area. Specifically an area along the coastline with a N-S direction, corresponding to the build up zone of Sharm El-Shiekh, shows average annual subsidence rates between -5 and -7 mm/yr along the line of sight (LOS). On the contrary, Sharm El Maya, an inner zone parallel to the above subsided area, shows slant range uplift of around 5 mm/yr. The obtained results of SAR inteferometry probably indicate the presence of an active fault that affects the coastal zones of Sharm El-Shiekh area

Flood Hazard Mapping in a Reservoir-regulated River Basin using Sentinel-1 imagery: The Case of Serres Basin.

International audienceFlood is a natural disaster and causes loss of life and property destruction. Flood hazard Monitoring and Mapping is of great importance because it represents a significant contribution to risk management. The present study investigated the flood event occurred in 2014-2015 at Serres Basin, a reservoir-regulated river basin, aiming to understand its spatio-temporal dynamic of the flood hazard. Within the Strymon River basin, a transboundary river outflows to Kerkini Lake-reservoir which has the role of regulating water flow to downstream for irrigation purposes and flood protection. For this research, a dataset of Sentinel-1 SAR GRD images was collected and processed covering the period of October 2014 – October 2015. Based on SAR images binary water and non-water products were generated and interpreted. Satellite Earth Observation has proved to be an effective tool for hazard dynamic extension mapping and in combination with hydro-meteorological data can be a significant knowledge in flood disaster management

Correlation of Ground Deformation Induced by the 6 February 2023 M7.8 and M7.5 Earthquakes in Turkey Inferred by Sentinel-2 and Critical Exposure in Gaziantep and Kahramanmaraş Cities

On 6 February 2023, an M7.8 devastating earthquake started rupturing the East Anatolian fault system in Turkey, resulting in intense shaking that lasted over a minute. A second earthquake of magnitude 7.5 struck near the city of Elbistan a few hours later. Both of these events are associated with the East Anatolian fault system. The earthquake sequence caused widespread damage and collapse of structures in densely populated areas throughout the Southern Turkey and Northern Syria regions and a very large number of human losses. This study focuses on the correlation of the ground deformation with the critical exposure of the infrastructures of Gaziantep and Kahramanmaraş cities. The estimation of the ground deformation of the affected area is achieved with the use of Copernicus Sentinel-2 products and the Normalized Cross Correlation algorithm (NCC) of image matching. The results of the East–West component show that specific sections of the region moved towards the East direction, reaching displacement measurements of 5.4 m, while other sections moved towards the West direction, reaching displacement measurements of 2.8 m. The results of the North–South component show that almost the whole affected area moved towards the North direction, with specific areas reaching displacements of 5.5 m, and a few exemptions, as some areas moved towards the South direction, with displacements reaching even 6.9 m. Regarding the cities of Kahramanmaraş and Gaziantep, their estimated movement direction is North-West and North-East, respectively, and is consistent with the movements of the Arabian and Anatolian Plates in which they are located. Important infrastructures of the study areas (education, museums, libraries, hospitals, monuments, airports, roads and railways) are superimposed on the findings, enabling us to detect the critical exposure rapidly

Deformation estimation of an earth dam and its relation with local earthquakes, by exploiting multitemporal synthetic aperture radar interferometry: Mornos dam case (Central Greece)

Monitoring dam performance is a critical parameter in maintaining a safe dam. Safety concerns include seepage, internal erosion, and seismic issues in the case that the dam is located in high seismic hazard areas. Seismic considerations for dam safety among others includes the expected dam's performance during seismic events. The scope of this research work concerns the capability to record potential deformation on the Mornos earth dam (central Greece) induced by major earthquake events that occurred in the broader area. For this purpose, a hybrid interferometry synthetic aperture radar (InSAR) method was applied using elements of conventional differential InSAR, short baseline interferometry approaches, and persistent scatterers interferometry. A time series of ascending and descending acquisitions of active microwave instrument/ ERS-1 and 2 and advanced synthetic aperture radar/ENVISAT scenes covering the period from 1993 to 2010 were interferometrically combined. Five very strong seismic events with epicenters close to the dam, at the same period, were considered as potential sources of deformation. The lake's water surface elevation was also considered as an additional factor of induced deformation. Results show a maximum deformation rate of ∼10 cm along the line of sight for the whole period. Although the observed deformation appears to be due to changes in water level following a particular pattern, this is interrupted over time, and these interruptions coincide in time with specific seismic events

Earthquake-induced deformation estimation of earth dam by multitemporal SAR interferometry: the Mornos Dam case (Central Greece)

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Detection and Monitoring of Active Faults in Urban Environments: Time Series Interferometry on the Cities of Patras and Pyrgos (Peloponnese, Greece)

Monitoring of active faults in urban areas is of great importance, providing useful information to assess seismic hazards and risks. The present study concerns the monitoring of the potential ground deformation caused by the active tectonism in the cities of Patras and Pyrgos in Western Greece. A PS interferometric analysis technique was applied using a rich data–set of ERS–1 & 2 SLC images. The results of the interferometric analysis were compared with the tectonic maps of the two cities. Patras show clearer uplift–subsidence results due to the more distinct fault pattern and intense deformation compared to the Pyrgos area, where more diffused deformation is observed, with no significant displacements on the surface

Spatio-temporal evolution of the deformation around the Rio-Patras fault (Greece) observed by synthetic aperture radar interferometry from 1993 to 2017

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