Limits of Detection of Gravimetric Signals on Earth - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Scientific Reports Année : 2018

Limits of Detection of Gravimetric Signals on Earth

S. Rosat
DG
J. Hinderer
  • Fonction : Auteur
  • PersonId : 936086

Résumé

Gravimetry is a well-established tool to probe the deep Earth's processes. Geophysical signals coming from the deep Earth, like the inner core free oscillations, have however never been detected. Challenging quests raise the question of the limits of detection of elusive signals at the Earth's surface. Knowledge of the instrumental limits and of the environmental noise level at a site is fundamental to judge the true sensitivity of an instrument. We perform a noise level comparison of various gravimeters and a long-period seismometer at the J9 gravimetric observatory of Strasbourg (France) to provide a reference of instrumental performances. We then apply a three-channel correlation analysis of time-varying surface gravity from superconducting gravimeter records to isolate the instrumental self-noise from the environmental noise. The self-noise coherence analysis shows that the instrumental noise level remains flat towards lower frequencies till 10 −4 Hz. At seismic frequencies, the self-noise is well explained by a Brownian thermal noise model. At daily and sub-daily timescales , self-noise is increasing with the period but to a much lesser extent than observed noise level. Observed Earth's ambient noise level at sub-seismic frequencies is hence mostly due to unmodeled geophysical processes. At hourly timescales , our ability to detect elusive signals coming from the deep Earth's interior is not limited by the instrument capability but is mostly due to the environmental effects.
Fichier principal
Vignette du fichier
s41598-018-33717-z.pdf (2.06 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-01897701 , version 1 (02-07-2020)

Licence

Paternité - Pas d'utilisation commerciale

Identifiants

Citer

S. Rosat, J. Hinderer. Limits of Detection of Gravimetric Signals on Earth. Scientific Reports, 2018, 8 (1), ⟨10.1038/s41598-018-33717-z⟩. ⟨hal-01897701⟩
39 Consultations
38 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More