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Ground Deformations Observed for Three Decades (1992-2022) above Old and Deep Coal Mines Reused for Deep Gas Storage Sites (Wallonia, Belgium) using PS-InSAR Time-series.
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The coal mining exploitations in Wallonia was gradually phased out till the end of the last century. Groundwater pumping was ceased, implying a groundwater rebound at varying rates that can still be observed by radar interferometry. The sustainability of architectural and technical facilities within those zones must be monitored to reduce environmental concerns during the post-mining phase and their reuse as gas storage reservoir locations. PS-InSAR approach has shown land surface deformations during three decades in a large area (96 km²) covering the cities from Binche to Anderlues (Wallonia, Belgium). Two coal mines are concerned: (i) to the West, the Ressaix-Mariemont-La Louvière concession where a small part was used as the Peronnes Gas Storage (PGS) reservoir; (ii) to the East, the Bois de la Haye concession where about half of the area has been used as the Anderlues Gas Storage (AGS) reservoir. To maintain the PGS reservoir dry, a private company has maintained groundwater pumping activities till 1998 with a dewatering rate of 40 m³/h. After 1998, the water levels raised from 8 m/yr at the beginning to 2.5 m/yr around 2010. The gas storage reservoir of Anderlues is known to be relatively dry. Using a multi-sensor radar dataset including radar images acquired by the European Space Agency’s satellites of ERS1/2, ENVISAT ASAR, and Sentinel-1A, 236 interferograms were constructed. Ground displacements are mapped and subdivided into three successive time intervals showing: (1) during ERS1/2 (1991-2000), a gradient from positive annual average velocities (West) to negative ones (East) across the PGS site and mostly negative values (-0.5 to -3.0 mm/yr) above the AGS site; (2) during ENVISAT ASAR (2003-2010), the positive LOS velocities (0.5 to 2.89 mm/yr) are present along an NW-SE ellipsoid across PGS leaving only negative LOS values in the NW corner while negative LOS velocities were also recorded along the Binche city (-0.5 to -2 mm/yr). During the same period, the AGS is facing negative LOS velocity values and extending to the south as well; (3) during Sentinel-1A (2015-2022), almost all the PGS is affected by positive annual LOS velocities (0.5 to about 4-5 mm/yr) even extending towards the north outside the limits of PGS. AGS is still affected by negative LOS values in the middle and SE parts. Ground displacements measured at the surface of old coal mine concessions and recent gas storage sites allow following the impact of the use of the subsurface through time.
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RBINS Staff Publications 2022 OA
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Ground Deformations Related to an Old Drainage Adit in The Abandoned Coal Concession Around Saint-Vaast (Wallonia, Belgium) Analysed Using PS-InSAR and Piezometric Wells Time Series
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The exploitations of the coal mines in Wallonia were ceased progressively till the end of the last century. Groundwater pumping’s were stopped inducing a groundwater rebound with different rates but still visible today with radar interferometry. To mitigate the threats to the environment during the post-mining period, flooding and outbreak risks, surface ground deformations and the stability of civil engineering infrastructures in the vicinity of those mined areas need to be monitored. The persistent scatterer radar interferometry technique (PS-InSAR) has revealed ground displacements during three decades in Saint-Vaast (Wallonia, Belgium). Under this residential area, an old drainage adit at a depth of approximately 30 m allows mine water discharge to the Haine river. A confined aquifer lies in this Wealdian sandy layer characterized by a weak mechanical resistance and frequent loose sandy pockets. The Saint-Vaast area has so far suffered twice from a clogging rupture in the drainage adit. The clog has induced an underground water pressure increase in the confined aquifer. This water outbreak resulted in a stream of mud, sand and water flowing out during a few days in 2009. This event has induced a displacement at the surface with cracks observed in the walls of several houses nearby. 236 interferograms were produced using images acquired by the ESA’s satellites (ERS1/2, ENVISAT and Sentinel-1A). A time serie of surface displacements from 1991 to 2022 is calculated. Land surface displacements trends before and after both events were recognized. During ERS1/2 (1992–2002) an uplift has a rate exceeding 3 mm/year. The saturation of the Wealdian aquifer sands reduces the effective intergranular stress leading to an uplift. Groundwater recharge slowed down after the uplift and turned to almost stability during ERS (2002-2006) and ENVISAT (2003–2010). The sudden water outbreak in 2009 has resulted in a localized land subsidence. Before and after the second outflow associated to a clog rupture in early 2018, a similar pattern of land surface deformations was observed. After 2018 (Sentinel-1A), the average LOS velocity values are -1.8 mm/year where the 2009 event occured. Piezometric wells drilled after the 2009 event are monitoring the groundwater levels in the Wealdian aquifer. Analysis of piezometric data combined with PS-InSAR allowed to compare the water table evolutions in the confined aquifer and the ground deformations observed at the surface.
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RBINS Staff Publications 2022 OA
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Revision of the genus Baltoplana (Rhabdocoela: Schizorhynchia: Cheliplanidae) with the description of two new species
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RBINS Staff Publications 2024
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Unraveling chromosomal inversions and their evolutionary dance in a wing polymorphic beetle
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RBINS Staff Publications 2024
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Symbiotic interactions challenged by environmental stress in aquatic transitional habitats
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RBINS Staff Publications 2024
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Comparison of the pollinator microbiome: management practices, altitude and sex as drivers for change
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RBINS Staff Publications 2024
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The green heart of Africa, the Lomami Primer
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RBINS Staff Publications 2024
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Evolution in the tides: unravelling adaptive strategies in Pogonus chalceus beetles
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RBINS Staff Publications 2024
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Revision of the longirostrine crocodilian Thoracosaurus isorhynchus from the Maastrichtian–Danian of northwestern Europe
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“Thoracosaurs” are a group of longirostrine eusuchians known from Upper Cretaceous–lower Paleogene coastal deposits of Europe and North America. Their phylogenetic position is highly debated and varies from one study to the next, ranging from inclusion within Gavialoidea—implying ghost lineages of up to 100 million years—to exclusion from Crocodylia altogether. Despite these issues, many “thoracosaur” taxa have been understudied, suffering from incomplete or outdated descriptions and questionable taxonomic assignment. We present a comprehensive revision of Thoracosaurus isorhynchus, the most common European “thoracosaur.” Here, we redescribe the lectotype and paralectotypes of the species from the Maastrichtian of Mont-Aimé, France, and a skull from the Maastricht type area, The Netherlands. We also add new, previously undescribed cranial and extensive postcranial material from Mont-Aimé. Moreover, comparison with the type material of Thoracosaurus “scanicus” of the Danian of southern Sweden indicates that the latter is a junior synonym of T. isorhynchus, confirming the persistence of this species across the Cretaceous–Paleogene boundary. An array of phylogenetic analyses points to a close relationship between T. isorhynchus and the Cenomanian Portugalosuchus azenhae. This implicates an early emergence of “thoracosaurs” within Gavialoidea, highlighting the stratigraphic inconsistency of this group and a need for up to date descriptions of species belonging to this group.
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RBINS Staff Publications 2025 OA
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Recent data on the enigmatic family Raoellidae: how aquatic…how cetacean?
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At the beginning of the 21st century, the discovery of an involucrum on the auditory bulla of Indohyus, a small raoellid artiodactyl from the Indian subcontinent, triggered the phylogenetic gathering of Raoellidae with the Cetacea clade, making them pivotal in addressing questions surrounding the land-to-water transition in Artiodactyla. Micro CT scan investigations and newly collected material from the Kalakot area (Jammu and Kashmir, India), recently greatly increased our knowledge of the cranial and dental features of this group. Here we present new data on cranial morphology of Raoellidae deriving from micro CT scan investigations of Indohyus indirae and Khirtharia inflata. This new body of data comprises investigations of the endocast of the braincase, the complete middle ear including the ossicles and auditory bulla, the petrosal bone, and the cast of the bony labyrinth. It also includes the reconstruction of the complete anterior dentition. This study gives us a comprehensive picture of the features of the Raoellidae head and improves our understanding of their semiaquatic habits. This increased knowledge of raoellids further extends the list of features they share with the first archeocetes, calling into question the definition of the clade Cetacea.
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RBINS Staff Publications 2025 OA
