Investigating recent seismotectonic activity of the Haubourdin fault in the Mélantois anticline area (Northern France) using LiDAR dataset and GPR survey - Archive ouverte HAL Accéder directement au contenu
Communication Dans Un Congrès Année : 2021

Investigating recent seismotectonic activity of the Haubourdin fault in the Mélantois anticline area (Northern France) using LiDAR dataset and GPR survey

Résumé

North of France belongs to a moderately active seismotectonic area across which several – likely active – structures are identified (i.e. onshore, along the Artois hills, and offshore, along Dover Strait). A few tens of kilometers south of the 1.2 millions inhabited Lille European Metropolis, the ~50-km-long, sub-vertical and N110°E-directed Haubourdin Fault is considered as potentially active during Quaternary times, according to the French Institute of Radiological Protection and Nuclear Safety (IRSN) database. The Haubourdin Fault strikes roughly parallel to the E-W open Mélantois Anticline that folds the Upper Cretaceous chalk and the underlying Paleozoic basement. The Mélantois Anticline mainly developed during the Tertiary reactivation of deep basement structures, located at the northern front of the Variscan fold-belt. Its recent activity is suggested by a decrease in the thickness of the Quaternary fluvial deposits of the Deûle river, which crosses the fold axis. To investigate and document the possible neotectonic activity of the Haubourdin Fault, we analyzed the morphology from a high-resolution topographic dataset (LiDAR). We extend the topographic analysis slightly eastward (i.e. Belgium) along the Rumes Fault, which might be connected to the Haubourdin Fault. Our analysis has identified three intriguing topographic features along the mapped Haubourdin and Rumes Faults. All these features are strikingly aligned along the N110°E trend. On the French side, these consist in two topographic scarps, with several meters throw in the Haubourdin-Sainghin-en-Mélantois region, and with a 1.5 m throw in the Wannehain region, near the Belgian border. On the Belgian side, near the Rumes city, we have identified a peculiar drainage anomaly with clear evidences of headward erosion and transient state evolution. All features could suggest a recent surface uplift, although a simple lithological effect cannot be discarded. To document the subsurface geometry of the Wannehain scarp, we surveyed a ground-penetrating radar (GPR) profile with 200, 80 and 20 MHz antennas. Our GPR results do not allow to identify a clear near-surface fault signal. However, a 25-30m deep structure could be suspected in the basement. Both our topographic and geophysical results are compared to our 3-D geological model of the Mélantois Anticline that we have been building with the MOVE software, from boreholes and geophysical datasets, in collaboration with the French Geological Survey (BRGM). In conclusion, our topographic analysis of two high-resolution datasets along the Haubourdin Fault (in France) and Rumes Fault (in Belgium), has brought out intriguing morphological features that might call for a recent activity along these faults. Unfortunately, our GPR preliminary investigations do not allow to discriminate 1) a neotectonic or 2) an erosional (lithological) origin for one observed scarp. These preliminary results calls upon further investigations, including digging paleoseismological trenches, to confirm/infirm the hypothesis of neotectonic activity of the Haubourdin-Rumes fault.

Domaines

Tectonique
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Dates et versions

hal-04386128 , version 1 (10-01-2024)

Identifiants

  • HAL Id : hal-04386128 , version 1

Citer

Fabien Graveleau, Frank Chanier, Louise Watremez, Rachid Ouchaou, Olivier Averbuch, et al.. Investigating recent seismotectonic activity of the Haubourdin fault in the Mélantois anticline area (Northern France) using LiDAR dataset and GPR survey. GHYMANCHE, Oct 2021, Wimereux, France. ⟨hal-04386128⟩
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