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International audience ; The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution. Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer. In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d'Apt (LSBB), a former military site with 3,4 km of buried galleries

International audience ; The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution. Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer. In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d'Apt (LSBB), a former military site with 3,4 km of buried galleries

International audience ; The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution. Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer. In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d'Apt (LSBB), a former military site with 3,4 km of buried galleries

International audience ; The study of karstic systems is mainly based on hydrodynamic and hydrochemical data collected at system inlets (rainfall) and outlets (springs). Indeed, some complementary data base coming from speleological and hydrogeological explorations of natural cavities exist. However, they are not completely representative of all the types of flows. These kinds of flow which have a large part in general hydrodynamics of a system are already the result of a structured organization of karst due to complex phenomena of limestone dissolution. Artificial galleries have the advantage to be easily accessible. Moreover, they cut randomly flows which are much less structured or not. Both types of information seem to be complementary in order to understand a karstic aquifer. In this paper, we focus on the hydrochemical and hydrodynamic study of unstructured flows of the Low-Noise Underground Laboratory of Rustrel- Pays d'Apt (LSBB), a former military site with 3,4 km of buried galleries

Geophysical Journal International, v. 155, n. 3, p. 981-990, 2003. http://dx.doi.org/10.1111/j.1365-246X.2003.02095.x ; International audience ; Since the decommission of the underground launching control room of the ground-based component of the French nuclear missile system, the whole installation has been turned into a cross-disciplinary underground laboratory. The LSBB is a unique low-noise underground laboratory because of its initial military conception and its location in the regional park of Luberon far from large cities, industry and heavy traffic. The deepest point is 500 m below the surface. At this depth a huge and non-conventional shielded cylindrical capsule is installed with no μ-metal, 1268 m3 in volume, with a residual electromagnetic noise lower than 2 fT Hz−1/2 above 10 Hz. As a result, fluctuations of the Earth's magnetic field under 10 Hz can be recorded at a very low-noise level with a low-Tc SQUID 3-D magnetometer. Taking advantage of the main gallery topology, a broad-band underground seismic array has been deployed since 2001. An analysis of data recorded simultaneously by the seismic underground array and by the magnetometer sensors during the Indian earthquake of 2001 January 26 is presented. Evidence of a magnetic field perturbation induced by the seismic waves at teleseismic distance (6250 km) is supported by a polarization analysis of seismic and magnetic signals. Spectral analysis shows specific frequency bands of perturbation related to physical processes such as ground water flow acceleration within the mountain structure.

Geophysical Journal International, v. 155, n. 3, p. 981-990, 2003. http://dx.doi.org/10.1111/j.1365-246X.2003.02095.x ; International audience ; Since the decommission of the underground launching control room of the ground-based component of the French nuclear missile system, the whole installation has been turned into a cross-disciplinary underground laboratory. The LSBB is a unique low-noise underground laboratory because of its initial military conception and its location in the regional park of Luberon far from large cities, industry and heavy traffic. The deepest point is 500 m below the surface. At this depth a huge and non-conventional shielded cylindrical capsule is installed with no μ-metal, 1268 m3 in volume, with a residual electromagnetic noise lower than 2 fT Hz−1/2 above 10 Hz. As a result, fluctuations of the Earth's magnetic field under 10 Hz can be recorded at a very low-noise level with a low-Tc SQUID 3-D magnetometer. Taking advantage of the main gallery topology, a broad-band underground seismic array has been deployed since 2001. An analysis of data recorded simultaneously by the seismic underground array and by the magnetometer sensors during the Indian earthquake of 2001 January 26 is presented. Evidence of a magnetic field perturbation induced by the seismic waves at teleseismic distance (6250 km) is supported by a polarization analysis of seismic and magnetic signals. Spectral analysis shows specific frequency bands of perturbation related to physical processes such as ground water flow acceleration within the mountain structure.

Geophysical Journal International, v. 155, n. 3, p. 981-990, 2003. http://dx.doi.org/10.1111/j.1365-246X.2003.02095.x ; International audience ; Since the decommission of the underground launching control room of the ground-based component of the French nuclear missile system, the whole installation has been turned into a cross-disciplinary underground laboratory. The LSBB is a unique low-noise underground laboratory because of its initial military conception and its location in the regional park of Luberon far from large cities, industry and heavy traffic. The deepest point is 500 m below the surface. At this depth a huge and non-conventional shielded cylindrical capsule is installed with no μ-metal, 1268 m3 in volume, with a residual electromagnetic noise lower than 2 fT Hz−1/2 above 10 Hz. As a result, fluctuations of the Earth's magnetic field under 10 Hz can be recorded at a very low-noise level with a low-Tc SQUID 3-D magnetometer. Taking advantage of the main gallery topology, a broad-band underground seismic array has been deployed since 2001. An analysis of data recorded simultaneously by the seismic underground array and by the magnetometer sensors during the Indian earthquake of 2001 January 26 is presented. Evidence of a magnetic field perturbation induced by the seismic waves at teleseismic distance (6250 km) is supported by a polarization analysis of seismic and magnetic signals. Spectral analysis shows specific frequency bands of perturbation related to physical processes such as ground water flow acceleration within the mountain structure.

Geophysical Journal International, v. 155, n. 3, p. 981-990, 2003. http://dx.doi.org/10.1111/j.1365-246X.2003.02095.x ; International audience ; Since the decommission of the underground launching control room of the ground-based component of the French nuclear missile system, the whole installation has been turned into a cross-disciplinary underground laboratory. The LSBB is a unique low-noise underground laboratory because of its initial military conception and its location in the regional park of Luberon far from large cities, industry and heavy traffic. The deepest point is 500 m below the surface. At this depth a huge and non-conventional shielded cylindrical capsule is installed with no μ-metal, 1268 m3 in volume, with a residual electromagnetic noise lower than 2 fT Hz−1/2 above 10 Hz. As a result, fluctuations of the Earth's magnetic field under 10 Hz can be recorded at a very low-noise level with a low-Tc SQUID 3-D magnetometer. Taking advantage of the main gallery topology, a broad-band underground seismic array has been deployed since 2001. An analysis of data recorded simultaneously by the seismic underground array and by the magnetometer sensors during the Indian earthquake of 2001 January 26 is presented. Evidence of a magnetic field perturbation induced by the seismic waves at teleseismic distance (6250 km) is supported by a polarization analysis of seismic and magnetic signals. Spectral analysis shows specific frequency bands of perturbation related to physical processes such as ground water flow acceleration within the mountain structure.

Geophysical Journal International, v. 155, n. 3, p. 981-990, 2003. http://dx.doi.org/10.1111/j.1365-246X.2003.02095.x ; International audience ; Since the decommission of the underground launching control room of the ground-based component of the French nuclear missile system, the whole installation has been turned into a cross-disciplinary underground laboratory. The LSBB is a unique low-noise underground laboratory because of its initial military conception and its location in the regional park of Luberon far from large cities, industry and heavy traffic. The deepest point is 500 m below the surface. At this depth a huge and non-conventional shielded cylindrical capsule is installed with no μ-metal, 1268 m3 in volume, with a residual electromagnetic noise lower than 2 fT Hz−1/2 above 10 Hz. As a result, fluctuations of the Earth's magnetic field under 10 Hz can be recorded at a very low-noise level with a low-Tc SQUID 3-D magnetometer. Taking advantage of the main gallery topology, a broad-band underground seismic array has been deployed since 2001. An analysis of data recorded simultaneously by the seismic underground array and by the magnetometer sensors during the Indian earthquake of 2001 January 26 is presented. Evidence of a magnetic field perturbation induced by the seismic waves at teleseismic distance (6250 km) is supported by a polarization analysis of seismic and magnetic signals. Spectral analysis shows specific frequency bands of perturbation related to physical processes such as ground water flow acceleration within the mountain structure.