Status of NESTOR, a deep sea neutrino telescope in the Mediterranean

Anassontzis, E.G.; Barone, M.; Fahrun, E.; Foudas, C.; Gialas, G.; Grammatikakis, G.; Katsanevas, S.; Kourkoumelis, C.; Manousakis-Katsikakis, A.; Odian, A.; Resvanis, L. K.; Siotis, I.; Sotiriou, Sofoklis; Voulgaris, G.; Ball, A.E.; Cartacci, A. M.; dell’Agnello, Luca; Monteleoni, B.; Naumov, Vadim A.; Perrone, L.; Martini, A.; Nicoletti, G.; Trasatti, L.; Valente, V.; Keusen, U.; Koske, P.; Rathlev, J.; Voigt, G. H.; Curti, F.; Marchis, G. De; Piccari, L.; Ameli, F.; Bonori, M.; Bosio, C.; Bottai, S.; Capone, A.; Desiati, P.; Massa, F.; Rikalin, V.; Valente, E.; Bezrukov, L.; Butkevich, A.; Dedenko, L. G.; Karaevsky, S. Kh.; Mironovich, A. A.; Zakharov, L.M.; Железных, И. М.; Жуков, В.; Demidova, T. A.; Deyneko, A; Eremeev, A.P.; Пака, В. Т.; Permyakov, Alexander; Platonov, M.N.; Rucol, V.K.; Сурин, Н. М.; Sheremet, N. A.; Albul, V. I.; Ledenev, V.V.

doi:10.1016/s0920-5632(98)00047-4

Cited by 6 publications

(2 citation statements)

References 1 publication

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“…DAS strain rate data were acquired along the contiguous HCMR (Hellenic Center for Marine Research) and NESTOR (Neutrino Extended Submarine Telescope with Oceanographic Research) fibre optic cables (Figure 1), located offshore Methoni at the deepest part of the Mediterranean in Greece, southwest of the Peloponnese (Collaboration et al 1994;Anassontzis et al 1998;Aggouras et al 2005). The HCMR cable communicates an on-land facility with an oceanography laboratory.…”

Section: Das Experiments On the Hcmr And Nestor Cablesmentioning

confidence: 99%

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

Flores

Mercerat²,

Ampuero

et al. 2023

Geophysical Journal International

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Summary Distributed Acoustic Sensing (DAS) enables data acquisition for underwater Earth Science with unprecedented spatial resolution. Submarine fibre optic cables traverse sea bottom features that can lead to suspended or decoupled cable portions, and are exposed to the ocean dynamics and to high rates of marine erosion or sediment deposition, which may induce temporal variations of the cable’s mechanical coupling to the ocean floor. Although these spatio-temporal fluctuations of the mechanical coupling affect the quality of the data recorded by DAS, and determine whether a cable section is useful or not for geophysical purposes, the detection of unsuitable cable portions has not been investigated in detail. Here, we report on DAS observations of two distinct vibration regimes of seafloor fibre optic cables: a high-frequency (>2 Hz) regime we associate to cable segments pinned between seafloor features, and a low-frequency (<1 Hz) regime we associate to suspended cable sections. While the low-frequency oscillations are driven by deep ocean currents, the high-frequency oscillations are triggered by the passage of earthquake seismic waves. Using Proper Orthogonal Decomposition, we demonstrate that high-frequency oscillations excite normal modes comparable to those of a finite 1D wave propagation structure. We further identify trapped waves propagating along cable portions featuring high-frequency oscillations. Their wave speed is consistent with that of longitudinal waves propagating across the steel armouring of the cable. The DAS data on cable sections featuring such cable waves are dominated by highly monochromatic noise. Our results suggest that the spatio-temporal evolution of the mechanical coupling between fibre optic cables exposed to the ocean dynamics and the seafloor can be monitored through the combined analysis of the two vibration regimes presented here, which provides a DAS-based method to identify underwater cable sections unsuitable for the analysis of seismic waves.

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Section: Das Experiments On the Hcmr And Nestor Cablesmentioning

confidence: 99%

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

Flores

Mercerat²,

Ampuero

et al. 2023

Geophysical Journal International

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“…Baksan [15], MACRO [16], Super-K [17] and AMANDA [18] released upper limits on the upward-going muon flux. There are also planned or proposed neutrino telescopes such as ANTARES [19], IceCube [20] and NESTOR [21] etc..…”

Section: Introductionmentioning

confidence: 99%

B_s→μ⁺μ⁻and the upward-going muon flux from the WIMP annihilation in the sun or the earth

Baek¹,

Kim²,

Ko³

2005

J. High Energy Phys.

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We consider the upward-going muon flux due to the WIMP annihilations in the cores of the sun and the earth, including the upper bound on the branching ratio for B s → µ + µ − decay. We find that the constraint from B s → µ + µ − is very strong in most parameter space, and exclude the supergravity parameter space regions where the expected upward-going muon fluxes are within the expected reach of AMANDA II.

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Identification of two vibration regimes of underwater fibre optic cables by Distributed Acoustic Sensing

Flores

Mercerat²,

Ampuero

et al. 2022

Preprint

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Distributed Acoustic Sensing (DAS) enables data acquisition for underwater Earth Science with unprecedented spatial resolution. Submarine fibre optic cables traverse sea bottom features that can lead to suspended or decoupled cable portions, and are exposed to the ocean dynamics and to high rates of marine erosion or sediment deposition, which may induce temporal variations of the cable's mechanical coupling to the ocean floor. Although these spatio-temporal fluctuations of the mechanical coupling affect the quality of the data recorded by DAS, and determine whether a cable section is useful or not for geophysical purposes, the detection of unsuitable cable portions has not been investigated in detail. Here, we report on DAS observations of two distinct vibration regimes of seafloor fibre optic cables: a high-frequency (> 2 Hz) regime we associate to cable segments pinned between seafloor features, and a low-frequency (< 1 Hz) regime we associate to suspended cable sections. While the low-frequency oscillations are driven by deep ocean currents, the high-frequency oscillations are triggered by the passage of earthquake seismic waves. Using Proper Orthogonal Decomposition, we demonstrate that high-frequency oscillations excite normal modes comparable to those of a finite 1D wave propagation structure. We further identify trapped waves propagating along cable portions featuring high-frequency oscillations. Their wave speed is consistent with that of longitudinal waves propagating across the steel armouring of the cable. The DAS data on cable sections featuring such cable waves are dominated by highly monochromatic noise. Our results suggest that the spatio-temporal evolution of the mechanical coupling between fibre optic cables exposed to the ocean dynamics and the seafloor can be monitored through the combined analysis of the two vibration regimes presented here, which provides a DAS-based method to identify underwater cable sections unsuitable for the analysis of seismic waves.

show abstract

Status of NESTOR, a deep sea neutrino telescope in the Mediterranean

Cited by 6 publications

References 1 publication

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

B_s→μ⁺μ⁻and the upward-going muon flux from the WIMP annihilation in the sun or the earth

Identification of two vibration regimes of underwater fibre optic cables by Distributed Acoustic Sensing

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Status of NESTOR, a deep sea neutrino telescope in the Mediterranean

Cited by 6 publications

References 1 publication

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

Identification of two vibration regimes of underwater fibre optic cables by distributed acoustic sensing

Bs→μ+μ−and the upward-going muon flux from the WIMP annihilation in the sun or the earth

Identification of two vibration regimes of underwater fibre optic cables by Distributed Acoustic Sensing

Contact Info

Product

Resources

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B_s→μ⁺μ⁻and the upward-going muon flux from the WIMP annihilation in the sun or the earth