<> "The repository administrator has not yet configured an RDF license."^^ . <> . . . "Induced Seismicity Monitoring of an Underground Salt Cavern Prone to Collapse"^^ . "Within the framework of a large research project\r\nlaunched to assess the feasibility of microseismic monitoring of\r\ngrowing underground caverns, this specific work focuses on the\r\nanalysis of the induced seismicity recorded in a salt mine environment.\r\nA local seismic network has been installed over an\r\nunderground salt cavern located in the Lorraine basin (Northeast of\r\nFrance). The microseismic network includes four 3-components\r\nand three single component geophones deployed at depths between\r\n30 and 125 m in cemented boreholes drilled in the vicinity of the\r\nstudy area. The underground cavern under monitoring is located\r\nwithin a salt layer at 180 m depth and it presents a rather irregular\r\nshape that can be approximated by a cylindrical volume of 50 m\r\nheight and 180 m diameter. Presently, the cavern is full of saturated\r\nbrine inducing a significant pressure on its walls (*2.0 MPa) to\r\nkeep the overburden mechanically stable. Nevertheless some small\r\nmicroseismic events were recorded by the network and analyzed\r\n(approximately 2,000 events in 2 years of recording). In October\r\n2005 and April 2007, two controlled pressure transient experiments\r\nwere carried out in the cavern, in order to analyze the mechanical\r\nresponse of the overburden by tracking the induced microseismicity.\r\nThe recorded events were mainly grouped in clusters of 3–\r\n30 s of signal duration with emergent first arrivals and rather low\r\nfrequency content (between 20 and 120 Hz). Some of these events\r\nhave been spatially located by travel-time picking close to the\r\nactual cavern and its immediate roof. Preliminary spectral analysis\r\nof isolated microearthquakes suggests sources with non-negligible\r\ntensile components possibly related to fluid-filled cracks. Rockdebris\r\nfalling into the cavern from delamination of clay marls in the\r\nimmediate roof is probably another source of seismic excitation.\r\nThis was later confirmed when the most important seismic swarms\r\noccurred at the site during May 2007, accompanied by the\r\ndetachment of more than 8 9 104 m3 of marly material on top of\r\nthe cavern roof. In any case, no clear evidence of classical brittle\r\nruptures in the most competent layers of the overburden has been\r\nobserved during the analyzed period. Current work is focused on\r\nthe discrimination of all these possible mechanisms to better\r\nunderstand the damage processes in the cavern overburden and to\r\nassess its final collapse hazard."^^ . "2010" . . "167" . "1-2" . . "Springer Verlag"^^ . . . "Pure and Applied Geophysics"^^ . . . "00334553" . . . . . . . . . . . "E. D."^^ . "Mercerat"^^ . "E. D. Mercerat"^^ . . "L."^^ . "Driad-Lebeau"^^ . "L. Driad-Lebeau"^^ . . "Pascal"^^ . "Bernard"^^ . "Pascal Bernard"^^ . . "Equipe de Sismologie, Institut de Physique du Globe de Paris"^^ . . . "INERIS, Ecole des Mines de Nancy"^^ . . . "GEODERIS"^^ . . . . . . "HTML Summary of #1953 \n\nInduced Seismicity Monitoring of an Underground Salt Cavern Prone to Collapse\n\n" . "text/html" . . . "Collective properties of seismicity" . . . "Lorraine salt basin" . . . "Underground mining" . .